Enzymatic Antinutritive Defenses of the Tomato Plant Against Insects

Chapter 12

Enzymatic Antinutritive Defenses of the Tomato Plant Against Insects Sean S. Duffey and Gary W. Felton

Downloaded by CORNELL UNIV on August 2, 2012 | http://pubs.acs.org Publication Date: January 9, 1991 | doi: 10.1021/bk-1991-0449.ch012

Department of Entomology, University of California, Davis, CA 95616

The tomato plant, Lycopersicon esculentum. contains constitutive and inducible chemical defenses that play a s i g n i f i c a n t role i n protection from attack by a v a r i e t y of insects and pathogens. Most studies on chemical bases of resistance of the tomato plant against insects have focused on c o n s t i t u t i v e , single-factor components which exert t h e i r e f f e c t upon the insect by d i r e c t l y poisoning it. We discuss an approach to resistance which r e l i e s upon the simultaneous action of multi-component constitutive and inducible defenses which i n d i r e c t l y retard insect growth by depriving the insect of essential nutrients. The d r i v i n g force of t h i s resistance i s predominantly derived from oxidative enzymes which, upon damage to the plant, activate c e r t a i n constitutive components to highly reactive a l k y l a t i n g agents ( e l e c t r o p h i l e s ) , which i n turn render dietary protein and other essential or l i m i t i n g nutrients unutilizable. The production of these electrophiles, i n conjunction with reduced protein quality (e.g., lowered sulphur amino acid intake), may also place a s t r a i n on the insect's a b i l i t y to generate reducing and conjugating agents (e.g., glutathione). Hence, not only i s nutrient intake by the insect compromised, but so may be the insect's a b i l i t y to detoxify natural and synthetic toxins. The benefits and detractions of t h i s approach i n terms of compatibility with b i o l o g i c a l control agents and biotechnological approaches to host plant resistance are discussed.

D u r i n g the l a s t decade our knowledge o f t h e bases and g e n e t i c s o f r e s i s t a n c e o f solanaceous crop p l a n t s to insects (see o t h e r c h a p t e r s i n t h i s volume) h a s i n c r e a s e d markedly. R e s i s t a n c e h a s been p r i m a r i l y based on the enhancement o f the l e v e l s o f one o r two constitutive chemical and/or physical resistance-conferring c h a r a c t e r i s t i c s i n commercial v a r i e t i e s v i a b r e e d i n g w i t h e x o t i c germplasm (see o t h e r c h a p t e r s i n the volume). The predominant mode 0097-6156/91/0449-0166$09.00/0 © 1991 American Chemical Society In Naturally Occurring Pest Bioregulators; Hedin, P.; ACS Symposium Series; American Chemical Society: Washington, DC, 1991.

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DUFFEY AND FELTON

Enzymatic Antinutritive Defenses of Tomato

o f h o s t p l a n t r e s i s t a n c e i s a n t i b i o s i s , whereby the i n s e c t s p e c i e s is directly poisoned and/or physically impeded by these c h a r a c t e r i s t i c s . I n c o n t r a s t , we d e s c r i b e an approach t o h o s t p l a n t r e s i s t a n c e o f the tomato p l a n t a g a i n s t n o c t u i d l a r v a e t h a t a t t e m p t s to derive resistance through antinutritive resistance. This r e s i s t a n c e r e s u l t s from the c h e m i c a l i n t e r a c t i o n o f a m u l t i t u d e o f plant factors that irreversibly limit the bioavailability of e s s e n t i a l or l i m i t i n g d i e t a r y n u t r i e n t s d u r i n g the e a r l y s t a g e s o f i n g e s t i o n and d i g e s t i o n o f p l a n t m a t e r i a l . A n t i n u t r i t i v e r e s i s t a n c e d e r i v e s from the a c t i o n o f s e v e r a l p l a n t o x i d a t i v e enzymes t h a t a c t i v a t e a v a r i e t y o f c h e m i c a l d e f e n s e s and n u t r i e n t s to n u t r i e n t d e s t r o y i n g agents.


Rationale f o r A n t i n u t r i t i v e Resistance G r e a t t h e o r e t i c a l importance has been g i v e n t o the r o l e o f p l a n t n i t r o g e n i n r e g u l a t i n g i n s e c t p o p u l a t i o n dynamics ( 1 - 7 ) . G e n e r a l e c o l o g i c a l t h e o r y a l s o proposes t h a t a c q u i s i t i o n o f p l a n t n i t r o g e n , a major h u r d l e f o r phytophagous i n s e c t s , can a l s o be hampered by the coingestion o f s e v e r a l types o f n a t u r a l p r o d u c t s (e.g., p h e n o l i c s , t a n n i n s , l i g n i n s , and p r o t e i n a s e i n h i b i t o r s ) (4,8-14) whose p u t a t i v e mode o f a c t i o n i n v o l v e s i n t e r f e r e n c e w i t h d i g e s t i v e p r o c e s s e s . I t i s s u r p r i s i n g t h a t h o s t - p l a n t r e s i s t a n c e programs do not i n c l u d e more c o n c e r t e d e f f o r t s t o employ r e s i s t a n c e aimed a t impeding u t i l i z a t i o n o f n i t r o g e n by i n s e c t s . The majority of r e s e a r c h on c h e m i c a l bases o f r e s i s t a n c e o f c r o p p l a n t s t o i n s e c t s has f o c u s e d on n a t u r a l p r o d u c t s t h a t are d i r e c t l y t o x i c , form p h y s i c a l b a r r i e r s , and/or are m o d i f i e r s o f b e h a v i o r (15-18). For sake o f argument, these a n t i b i o t i c f a c t o r s can be v i e w e d as " p o s i t i v e " t r a i t s o f r e s i s t a n c e because t h e i r b i o a v a i l a b i l i t y i n the p l a n t p e r m i t s them t o e x e r t t h e i r d i r e c t e f f e c t s a f t e r c o n t a c t with the insect. In contrast, i t i s also possible t o have " n e g a t i v e " r e s i s t a n c e , w h i c h r e s u l t s from the absence o r d e f i c i t o f p l a n t c h e m i c a l t r a i t s t h a t are e s s e n t i a l o r l i m i t i n g f o r the i n s e c t . I n p r i n c i p l e , the p u t a t i v e a n t i d i g e s t i v e p r o p e r t i e s of t a n n i n s and g o s s y p o l r e p r e s e n t n e g a t i v e r e s i s t a n c e because they are thought to reduce the d i g e s t i o n and u t i l i z a t i o n o f d i e t a r y p r o t e i n (19-21), a l t h o u g h such a n t i d i g e s t i v e a c t i o n i s q u e s t i o n e d (22-26). In theory, such r e s i s t a n c e r e s u l t s from a c h e m i c a l l y reduced b i o a v a i l a b i l i t y o f n u t r i e n t s e s s e n t i a l f o r growth an development. Thus, the i n s e c t i s not poisoned d i r e c t l y (or i t s behavior m o d i f i e d ) by an o v e r l o a d o f a l l e l o c h e m i c a l s , b u t r a t h e r i n d i r e c t l y by a d e f i c i t o f e s s e n t i a l n u t r i e n t s . " N e g a t i v e " r e s i s t a n c e has been documented i n a pea c u l t i v a r a g a i n s t an a p h i d and i n a r i c e c u l t i v a r a g a i n s t a leaf-hopper because o f reduced q u a n t i t i e s o f amino a c i d s ( 1 8 ) . G e n e r a l l y , the d e t r i m e n t a l e f f e c t upon a p h i d s o f absence or l i m i t a t i o n o f s p e c i f i c amino a c i d s has been c o m p a r a t i v e l y w e l l s t u d i e d (27-29). A l s o , the r e s i s t a n c e o f maize to the European c o r n b o r e r has been r e l a t e d to i n s u f f i c i e n t l e v e l s o f a s c o r b i c a c i d t o p e r m i t p r o p e r growth ( 3 0 ) . A v a r i e t y o f o t h e r p l a n t n a t u r a l p r o d u c t s are known to a d v e r s e l y a f f e c t the i n s e c t ' s a b i l i t y t o u t i l i z e food. Saponins have been i m p l i c a t e d as a n t i t r y p t i c agents (31) and were a l s o shown to i n t e r f e r e w i t h c h o l e s t e r o l a b s o r p t i o n (31,32). α-Amylase i n h i b i t o r s are p o t e n t i n h i b i t o r s o f amylase d i g e s t i o n i n b e e t l e s (33,34).

In Naturally Occurring Pest Bioregulators; Hedin, P.; ACS Symposium Series; American Chemical Society: Washington, DC, 1991.

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L i p o x y g e n a s e has been shown t o degrade e s s e n t i a l f a t t y a c i d s ( e . g . , l i n o l e i c ) as w e l l as produce t o x i c m e t a b o l i t e s ( 3 5 ) . The a b i l i t y t o u t i l i z e such f a c t o r s as n e g a t i v e forms o f r e s i s t a n c e has n o t been explored f u l l y . U s i n g the tomato p l a n t L y c o p e r s i c o n esculentum. we have been e x p l o r i n g the p o s s i b i l i t y o f u t i l i z i n g p l a n t enzymes t o a c t i v a t e c o n s t i t u t i v e d e f e n s e s and n u t r i e n t s t o c h e m i c a l l y r e a c t i v e p r o d u c t s t h a t reduce the u t i l i z a t i o n o f d i e t a r y p l a n t n i t r o g e n , and hence, c o n f e r n e g a t i v e r e s i s t a n c e a g a i n s t the tomato f r u i t w o r m H e l i o t h i s zea and the b e e t armyworm Spodoptera e x i g u a ( F i g u r e s 1 & 2) . The d e t r i m e n t a l e f f e c t s o f these enzymatic r e a c t i o n s o c c u r d u r i n g the e a r l y s t a g e s o f f e e d i n g upon f o l i a g e . These enzymes are p r i m a r i l y o x i d a t i v e (polyphenol oxidase, peroxidase, lipoxygenase), although a variety o f enzymes have p o t e n t i a l r o l e s (e.g., c a t a l a s e , s u p e r o x i d e dismutase, g l u t a t h i o n e r e d u c t a s e , and p h e n y l a l a n i n e and t y r o s i n e ammonia l y a s e s ) i n m o d u l a t i n g the a n t i n u t r i t i v e e f f e c t . B i o c h e m i c a l Nature o f Response o f P l a n t t o Wounding. One aim o f our program i s t o u t i l i z e some o f the immediate d e f e n s e s o f p l a n t s t o a t t a c k by m i c r o o r g a n i s m s c o i n c i d e n t a l l y a g a i n s t i n s e c t s . P l a n t s have a g e n e r a l i z e d d e f e n s i v e response t o wounding t h a t can be a r b i t r a r i l y d i v i d e d i n t o two phases a c t i v a t i o n and i n d u c t i o n . A c t i v a t i o n r e p r e s e n t s the immediate response t o c e l l u l a r damage w h e r e i n c e l l i n t e g r i t y i s l o s t and a v a r i e t y o f h y d r o l y t i c ( e . g . , a c y l l i p a s e s , c h i t i n a s e s , and g l u c a n a s e s ) and o x i d a t i v e ( e . g . , l i p o x y g e n a s e s , p o l y p h e n o l o x i d a s e s , and p e r o x i d a s e s ) enzymes are r e l e a s e d from c o m p a r t m e n t a l i z a t i o n . T h i s r e l e a s e r e s u l t s i n the g e n e r a t i o n o f c h e m i c a l s i g n a l s t h a t t r i g g e r the s y s t e m i c and/or l o c a l i n d u c t i o n of defenses (e.g., l i g n i f i c a t i o n , i s o f l a v o n o i d s , phenolics, and proteinase inhibitors) (36-46), and in the g e n e r a t i o n o f c h e m i c a l l y r e a c t i v e p r o d u c t s t h a t l e a d t o c e l l death through d e s t r u c t i o n o f membranes and p o l y m e r i z a t i o n o f c e l l u l a r components (38,42,43,47-50). This polymerization is primarily m e d i a t e d by p o l y p h e n o l o x i d a s e s , p e r o x i d a s e s , and lipoxygenases. Such p o l y m e r i z a t i o n l e a d s t o an i n s o l u b l e m a t r i x t h a t i s thought t o p r e s e n t a p h y s i c a l b a r r i e r t o the p r o g r e s s i o n o f d i s e a s e (51-57). These enzymes (e.g., lipoxygenases, polyphenol oxidases, p e r o x i d a s e s ) a l s o o c c u r i n the tomato p l a n t and are l o c a l l y and/or s y s t e m i c a l l y i n d u c i b l e , as a r e s u l t o f i n f e c t i o n by pathogens (49,53,55,58-62). I t s h o u l d f o l l o w t h a t they are a l s o i n d u c i b l e by i n s e c t - f e e d i n g damage such as t h a t i n f l i c t e d by H. zea o r S. e x i g u a . and a m p l i f y the a n t i n u t r i t i v e defense. A b r i e f d i s c u s s i o n o f the c h e m i c a l r e a c t i v i t y o f the p r o d u c t s o f t h e s e enzymes i s c e n t r a l t o our p r o p o s e d use o f these enzymes as a n t i n u t r i t i v e bases o f r e s i s t a n c e . P o l y p h e n o l o x i d a s e (PPO) and p e r o x i d a s e (POD) o x i d i z e p h e n o l i c s t o quinones, w h i c h are s t r o n g electrophiles t h a t a l k y l a t e n u c l e o p h i l i c f u n c t i o n a l groups of p r o t e i n , p e p t i d e s , and amino a c i d s ( e . g . , -SH, -ΝΗο, -ΗΝ-, and OH)(Figure 1)(53,63-65). T h i s a l k y l a t i o n r e n d e r s the d e r i v a t i z e d amino a c i d s n u t r i t i o n a l l y i n e r t , o f t e n reduces the d i g e s t i b i l i t y o f p r o t e i n by t r y p t i c and c h y m o t r y p t i c enzymes, and f u r t h e r m o r e can l e a d t o l o s s o f n u t r i t i o n a l v a l u e o f p r o t e i n v i a p o l y m e r i z a t i o n and subsequent d e n a t u r a t i o n and p r e c i p i t a t i o n (63,66-69). POD i s a l s o c a p a b l e o f d e c a r b o x y l a t i n g and d e a m i n a t i n g f r e e and bound amino acids to aldehydes (e.g., lysine, valine, phenylalanine,


12.

DUFFEY AND FELTON


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I II

di-quinonimin« F i g u r e 1. A S i m p l i f i e d V e r s i o n o f Some C h e m i c a l Reactions M e d i a t e d by P o l y p h e n o l Oxidase and P e r o x i d a s e t h a t C o n t r i b u t e t o Impairment o f P r o t e i n Q u a l i t y . D e t a i l s o f r e a c t i o n s and endproducts are not specified. diphenol generalized ο-dihydroxy-phenolic; aldehyde product derived from g e n e r a l i z e d amino a c i d .


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malondialdohydo

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F i g u r e 2. A S i m p l i f i e d V e r s i o n o f Some C h e m i c a l R e a c t i o n s M e d i a t e d b y Lipoxygenase t h a t C o n t r i b u t e t o Impairment o f P r o t e i n Q u a l i t y . Only t h e c i s . c i s - 1 . 4 - p e n t a d i e n e p o r t i o n o f a fatty acid i s indicated: cys-protein - cysteine i n protein. D e t a i l s o f r e a c t i o n s and end-products a r e n o t s p e c i f i e d .


12.

DUFFEY AND FELTON


m e t h i o n i n e , and l e u c i n e ) , f u r t h e r r e s u l t i n g i n n u t r i t i o n a l l o s s (Figure 1)(57,70,71). These aldehydes ( i n protein) facilitate p o l y m e r i z a t i o n by f o r m i n g S c h i f f bases w i t h -NH f u n c t i o n s o f o t h e r p r o t e i n m o l e c u l e s . POD c a n a l s o i n i t i a t e f r e e r a d i c a l f o r m a t i o n on -SH and tyrosinyl functions of protein, which leads to polymerization of protein and possible nutritive loss (63,65,69,72). L i p o x y g e n a s e (LOX) c o n v e r t s p o l y u n s a t u r a t e d f a t t y a c i d s , such as linoleic and linolenic acids, to l i p i d hydroperoxides (Figure 2)(52,73,74). The lipid hydroperoxides then form h y d r o p e r o x i d e r a d i c a l s , e p o x i d e s , and/or a r e degraded t o form m a l o n d i a l d e h y d e . These p r o d u c t s a r e a l s o s t r o n g l y e l e c t r o p h i l i c , and can destroy i n d i v i d u a l amino acids by decarboxylative deamination (e.g., lysine, cysteine, histidine, t y r o s i n e , and tryptophan); cause f r e e r a d i c a l m e d i a t e d c r o s s - l i n k i n g o f p r o t e i n a t t h i o l , h i s t i d i n y l , and t y r o s i n y l groups; and cause S c h i f f base f o r m a t i o n (e.g., m a l o n d i a l d e h y d e and l y s i n e a l d e h y d e ) (39,49,50,7478). Hence, these oxidative enzymes have the p o t e n t i a l to c h e m i c a l l y d e s t r o y a v a r i e t y o f e s s e n t i a l o r l i m i t i n g amino a c i d s (e.g. a r g i n i n e , c y s t e i n e , h i s t i d i n e , l e u c i n e , l y s i n e , m e t h i o n i n e , s e r i n e , t r y p t o p h a n , and t y r o s i n e ) ( 2 7 ) . I n a d d i t i o n , l i n o l e i c a c i d , a n o t h e r e s s e n t i a l d i e t a r y component (27) i s d e s t r o y e d . These r e a c t i o n s ( F i g u r e s 1 & 2) r e p r e s e n t t h e a c t i v a t i o n o f c o n s t i t u t i v e d e f e n s e s and n u t r i e n t s t o p o t e n t a n t i n u t r i t i v e a g e n t s . PPO, POD, and LOX a c t i v i t i e s a r e i m m e d i a t e l y r e l e a s e d when noctuid larvae masticate foliage. Depending upon substrate a v a i l a b i l i t y , these a c t i v i t i e s p e r s i s t i n the gut during d i g e s t i o n , and o f t e n p e r s i s t i n t h e f a e c e s (79: u n p u b l . d a t a ) . The p H - a c t i v i t y profiles o f t h e s e enzymes p e r m i t t h e i r a c t i o n i n t h e b a s i c environment o f t h e d i g e s t i v e f l u i d . PPO and POD a r e r e s i s t a n t t o i n a c t i v a t i o n by a v a r i e t y o f p r o t e a s e s (e.g., i n s e c t and b o v i n e t r y p s i n and c h y m o t r y p s i n , c a t h e p s i n , pepsin, and p r o n a s e ) ( 7 9 ; u n p u b l . d a t a ) . T h i s e x t e n s i v e a c t i o n p r o v i d e s t h e a p p r o p r i a t e time frame f o r s i g n i f i c a n t d e p r e c i a t i o n o f n u t r i t i o n a l q u a l i t y by t h e above mechanisms.


2

N u t r i t i o n a l Consequences. These o x i d a t i v e enzymes c a n have a major d e s t r u c t i v e impact upon d i e t a r y p r o t e i n and f r e e amino a c i d s (e.g., a r g i n i n e , c y s t e i n e , h i s t i d i n e , l y s i n e , m e t h i o n i n e , t r y p t o p h a n , and t y r o s i n e ) ( F i g u r e s 1 & 2 ) . Our p r o j e c t e d use o f t h e s e defensive r e a c t i o n s as an a n t i n u t r i t i v e form o f r e s i s t a n c e i s w e l l j u s t i f i e d by s t u d i e s on n u t r i t i o n o f v e r t e b r a t e s . The n e g a t i v e impact o f PPO and POD a c t i v i t y ( w i t h c h l o r o g e n i c o r c a f f e i c a c i d s as s u b s t r a t e s ) on p r o t e i n q u a l i t y f o r a n i m a l s i s w e l l e s t a b l i s h e d (63,66,69,8087). The primary negative effect i s exerted by reducing d i g e s t i b i l i t y o f p r o t e i n and a s s i m i l a t i o n o f d i g e s t e d protein through p r e c i p i t a t i o n , d e s t r u c t i o n o f s i t e s o f a t t a c k o f t r y p t i c (e.g., a t l y s i n e and a r g i n i n e ) and c h y m o t r y p t i c ( a t t y r o s i n e and t r y p t o p h a n ) enzymes, as w e l l as d e s t r u c t i o n o f o t h e r e s s e n t i a l o r limiting amino acids such as h i s t i d i n e , proline, cysteine, m e t h i o n i n e (63,65,84,87-90). Note t h a t many o f t h e s e amino a c i d s are e s s e n t i a l amino a c i d s f o r i n s e c t s (27,28). Some d e p r e c i a t i o n o f p r o t e i n q u a l i t y c a n a l s o r e s u l t from i n h i b i t i o n o f d i g e s t i v e enzymes by r e a c t i v e p r o d u c t s (91,92).


171


172


The n u t r i t i o n a l r e q u i r e m e n t s o f t h e s e i n s e c t s have been s t u d i e d t o a v e r y l i m i t e d degree. A v a r i e t y o f L-amino a c i d s are indispensable f o r growth o f H. zea (valine, leucine, lysine, arginine, histidine, isoleucine, tryptophan, tyrosine, p h e n y l a l a n i n e , and m e t h i o n i n e ) ( 9 3 ) , the v e r y amino a c i d s d e s t r o y e d by t h e s e o x i d a t i v e enzymes. A d d i t i o n a l l y , we have demonstrated t h a t the growth o f b o t h H. zea and S. e x i g u a i s s t r o n g l y i n h i b i t e d by l o w - q u a l i t y d i e t a r y p r o t e i n regimes w h i c h are p a r t i c u l a r l y poor i n l y s i n e and s u l f u r amino a c i d s (79,94-97). L y s i n e and s u l f u r amino a c i d s are among the most s e n s i t i v e t o such o x i d a t i v e / a l k y l a t i v e reactions. The p r o t e o l y t i c gut enzymes o f H. zea and S. e x i g u a have been shown t o be i n m a j o r i t y t r y p s i n and i n m i n o r i t y c h y m o t r y p s i n ( 9 4 ) , w h i c h r e q u i r e b a s i c ( l y s i n e and a r g i n i n e ) and a r o m a t i c ( t y r o s i n e and t r y p t o p h a n ) amino a c i d s , r e s p e c t i v e l y , as s i t e s t o h y d r o l y z e p r o t e i n . Hence, d e r i v a t i z a t i o n o f t h e s e p r o t e i n - b o u n d o r f r e e amino a c i d s by any o f the r e a c t i v e enzyme-products s h o u l d l e a d t o reduced u t i l i z a b i l i t y of d i e t a r y nitrogen. The d e t r i m e n t a l e f f e c t s o f t h e s e enzyme-mediated chemical r e a c t i o n s upon d i e t a r y n i t r o g e n s h o u l d be m a n i f e s t e d i n insects such as H. zea and S. e x i g u a i n i t i a l l y as r e d u c e d growth r a t e and s u b s e q u e n t l y as p o t e n t i a l l y d e t r i m e n t a l e f f e c t s on life-history t r a i t s ( e . g . , l o n g e v i t y , f e c u n d i t y , and s u r v i v o r s h i p ) ( 9 7 , 9 8 ) . Evidence f o r A n t i n u t r i t i o n a l

Resistance

The Tomato P l a n t . Does the tomato p l a n t p r o v i d e the a p p r o p r i a t e chemical m i l i e u necessary to create "negative r e s i s t a n c e " ? High l e v e l s o f c o n s t i t u t i v e PPO and POD e x i s t i n f o l i a g e (53,54,59,60, 79,99-101). A l s o , the l e v e l s o f f o l i a r PPO and POD i n c r e a s e a f t e r a t t a c k by m i c r o o r g a n i s m s (55,59,62,100), as w e l l as by i n s e c t s ( 6 1 ) . C a t a l a s e has been i d e n t i f i e d i n the tomato p l a n t (60; F e l t o n and D u f f e y , u n p u b l . ) . The s u b s t r a t e s f o r PPO and POD a c t i v i t y are ample i n f o l i a g e and g r e e n f r u i t o f the tomato p l a n t . C h l o r o g e n i c acid, rutin, q u e r c e t i n , c a f f e i c a c i d , and c a f f e o y l g l u t a r i c a c i d , and other c a f f e o y l d e r i v a t i v e s o c c u r i n the tomato p l a n t w i t h c h l o r o g e n i c a c i d and r u t i n p r e d o m i n a t i n g (99,102-104). Most o f t h e s e p h e n o l i c s have been r e p o r t e d as substrates f o r PPO and POD activity (66,69,81,83,84,87,105). Our assays w i t h tomato p l a n t PPO and POD show t h a t c h l o r o g e n i c a c i d and c a f f e i c a c i d s are good s u b s t r a t e s for t h e s e enzymes; whereas, r u t i n i s poor. Moreover, c a t e c h o l i c p h e n o l i c s ( e . g . , c h l o r o g e n i c a c i d and r u t i n ) a r e a l s o i n d u c i b l e above c o n s t i t u t i v e l e v e l s a f t e r a t t a c k by m i c r o o r g a n i s m s (106-110). I n t o b a c c o , PPO and POD are i n d u c e d b o t h l o c a l l y and s y s t e m i c a l l y by a t t a c k from Fusarium (49,57). L i k e w i s e , LOX occurs c o n s t i t u t i v e l y i n tomato f r u i t and l e a v e s (49,58,60,111-113). Both Type I and I I LOX's a r e p r e s e n t i n the tomato f r u i t w h i c h produce b o t h l i p i d h y d r o p e r o x i d e s (of linoleic and linolenic acids) and carbonyls (e.g., m a l o n d i a l d e h y d e ) ( 4 9 , 5 8 ) . The tomato v a r i e t y " C a s t l e m a r t " shows low l e v e l s o f c o n s t i t u t i v e LOX type I a c t i v i t y , b u t much h i g h e r l e v e l s have been found i n w i l d s p e c i e s o f L y c o p e r s i c o n . p a r t i c u l a r l y i n L. h i r s u t u m f . g l a b r a t u m (99; u n p u b l . d a t a ) . I t has been s u g g e s t e d


12.

DUFFEY AND FELTON



t h a t i n d u c e d LOX a c t i v i t y c o n t r i b u t e s t o r e s i s t a n c e o f soybean t o m i t e s (114,115); t h i s enzyme i s induced by a p h i d f e e d i n g (116). For purposes of breeding, our survey of the genus L y c o p e r s i c o n p o i n t s t o a c c e s s i o n s o f L. h i r s u t u m f . g l a b r a t u m as the b e s t sources o f p h e n o l i c s , PPO, POD, and LOX (99; u n p u b l d a t a ) . Proteinase I n h i b i t o r s i n Resistance. Proteinase i n h i b i t o r s (Pi's) have a t t r a c t e d c o n s i d e r a b l e a t t e n t i o n because t h e i r i n d u c i b l e nature, i n conjunction with t h e i r a n t i p r o t e o l y t i c p r o p e r t i e s , o f f e r the p l a n t the p o s s i b i l i t y o f e f f e c t i v e " p o s t - i n f e c t i o n a l " defense a g a i n s t c e r t a i n p e s t i n s e c t s (15,46,117-119). The promise o f t h i s form o f r e s i s t a n c e has l e d s e v e r a l r e s e a r c h groups t o t r a n s f e r and/or a m p l i f y the genes f o r p r o t e i n a s e i n h i b i t o r p r o d u c t i o n i n ( t o ) s e v e r a l crop p l a n t s (119-122). I n the tomato p l a n t , L. esculentum. damage t o f o l i a g e o f young p l a n t s by the f e e d i n g o f l a r v a l S. e x i g u a and H. zea induces the de novo p r o d u c t i o n o f P i ' s I and I I (123-125). I n the case o f S. e x i g u a . PI p r o d u c t i o n was d o u b l e d by f e e d i n g damage; growth was n e g a t i v e l y c o r r e l a t e d w i t h f e e d i n g damage (79,123,124). R e d u c t i o n o f l a r v a l growth r e s u l t s from s e v e r a l causes. The P I , as w e l l as i n h i b i t i n g a l i m e n t a r y p r o t e o l y t i c a c t i v i t y , induces an h y p e r t r o p h i c s y n t h e s i s o f t r y p s i n i n the i n s e c t ' s gut. T h i s i n d u c t i o n o f t r y p s i n i n c r e a s e s the i n s e c t ' s demand f o r d i e t a r y s u l p h u r amino a c i d s ; the n e t uptake o f s u l p h u r amino a c i d s i s s i m u l t a n e o u s l y b e i n g reduced because o f the a n t i p r o t e o l y t i c a c t i o n o f the P i ' s . Hence, the i n s e c t e n t e r s a p e r n i c i o u s s t a t e o f l i m i t a t i o n o f s u l p h u r amino a c i d s where the h y p e r t r o p h i c s y n t h e s i s o f t r y p s i n d e t r a c t s from r a p i d growth. The h i g h e r demand f o r s u l p h u r amino a c i d s can be met by the d i e t a r y p r o t e i n r i c h i n s u l p h u r amino a c i d s , and/or by a s u r p l u s o f f r e e s u l p h u r amino a c i d s i n the d i e t (94,95). I n f a c t , the degree o f growth i n h i b i t o r y e f f e c t s o f P i ' s i s i n v e r s e l y r e l a t e d t o the n u t r i t i o n a l q u a l i t y o f the d i e t a r y p r o t e i n . P r o t e i n s r e l a t i v e l y r i c h i n l y s i n e , a r g i n i n e , and s u l p h u r amino a c i d s reduce the t o x i c i t y o f PI s u b s t a n t i a l l y compared t o p r o t e i n s low i n these amino a c i d s (94-96). I n t h e o r y , the a n t i d i g e s t i v e p r o p e r t i e s o f P i ' s combined w i t h the above enzyme-based d e f e n s e s s h o u l d p r o v i d e "double-barrel" n e g a t i v e r e s i s t a n c e , s i n c e the f i r s t i n c r e a s e s the need f o r s u l p h u r amino a c i d s , and the second has the p o t e n t i a l t o d e c r e a s e the a v a i l a b i l i t y o f these and o t h e r amino a c i d s . However, i n o r d e r t o j o i n t l y u t i l i z e these two d e f e n s e s e f f e c t i v e l y , a deeper knowledge of their chemical interrelationships i s necessary. Potential c o m p l i c a t i o n s i n the use o f p r o t e i n a s e i n h i b i t o r s w i l l be d i s c u s s e d below. Polyphenol Oxidase. Peroxidase, and L i p o x y g e n a s e i n R e s i s t a n c e . Polyphenol oxidase i n c o n j u n c t i o n w i t h c h l o r o g e n i c a c i d as a s u b s t r a t e has the p o t e n t i a l t o reduce the a b i l i t y o f l a r v a l H. zea and S. e x i g u a t o u t i l i z e d i e t a r y p r o t e i n . For example, a l k y l a t i o n o f c a s e i n i n a r t i f i c i a l d i e t ( a t 1.0% wwt) by PPO (from mushroom o r tomato p l a n t ) and c h l o r o g e n i c a c i d , a t l e v e l s commensurate w i t h t h a t found i n tomato f o l i a g e , i n h i b i t s the growth o f b o t h l a r v a l s p e c i e s by up t o 70% (Table I ) . R u t i n i s a v e r y poor s u b s t r a t e f o r mushroom t y r o s i n a s e and tomato PPO (79; unpubl d a t a ) , and hence,


173

174


has n e g l i g i b l e e f f e c t upon p r o t e i n however, i t i s an a n t i b i o t i c i n i t s own

Table I.

H e l i o t h i s zea


Control

100

mM

CHA

7.0

mM

CHA

by

alkylation;

I n f l u e n c e o f CHA and PPO on R e l a t i v e Growth o f H e l i o t h i s zea and Spodoptera e x i g u a

Treatment

7.0

utilization r i g h t (97).

+ PPO

Spodoptera e x i g u a

a

100a

48.6b

58b

29.7c

42c

CHA - chlorogenic a c i d a t 7.0 mM/kg d i e t wwt.;PP0 0.100 O.D./min/gm d i e t : D i e t a r y p r o t e i n i s c a s e i n a t 1.0 % wwt.; larvae were grown on d i e t from neonate s t a g e t o 10 days o l d . S i g n i f i c a n t d i f f e r e n c e s between means w i t h i n a column, b a s e d on 95% c o n f i d e n c e i n t e r v a l s from ANOVA, are shown by d i f f e r e n t l e t t e r s .

The d e p r e c i a t i o n o f p r o t e i n q u a l i t y i s not r e s t r i c t e d to c a s e i n . The growth o f l a r v a l H. zea depends on the q u a l i t y and q u a n t i t y o f d i e t a r y p r o t e i n (96,97) w h i c h i s h i g h l y c o r r e l a t a b l e w i t h the r e l a t i v e l e v e l s o f c e r t a i n amino a c i d s ( l y s i n e , c y s t e i n e , h i s t i d i n e , and m e t h i o n i n e ) ( T a b l e I I ) . P r o t e i n s w i t h low amounts o f t h e s e amino a c i d s s u p p o r t growth p o o r l y . These amino a c i d s are the most s u s c e p t i b l e t o a l k y l a t i o n by o-quinones p a r t i c u l a r l y i n the basic conditions o f the gut. Therefore, i t follows that the s e v e r i t y o f r e d u c t i o n o f the n u t r i t i v e q u a l i t y o f a p r o t e i n i s dependent upon i t s q u a n t i t y and q u a l i t y (amount o f the above amino a c i d s as a l k y l a t a b l e amino a c i d s - AAA; T a b l e I I ) . C a s e i n , w h i c h i s the most n u t r i t i v e p r o t e i n t e s t e d and has the h i g h e s t r e l a t i v e q u a n t i t i e s o f AAA, i s the l e a s t a f f e c t e d by a l k y l a t i o n . I f a v a r i e t y o f p r o t e i n s , a t s i m i l a r d i e t a r y c o n c e n t r a t i o n s and s i m i l a r exposures t o the c o m b i n a t i o n o f PPO + c h l o r o g e n i c a c i d ( t o produce c h l o r o g e n o q u i n o n e ) , are compared f o r t h e i r a b i l i t y t o support growth o f e i t h e r i n s e c t , the l e a s t n u t r i t i o u s p r o t e i n s (e.g., g l u t e i n and tomato p r o t e i n ) are the most a f f e c t e d by a l k y l a t i o n compared t o soy p r o t e i n or c a s e i n . Amino a c i d a n a l y s e s o f t r e a t e d p r o t e i n s show l o s s e s o f up t o 30% o f e s s e n t i a l amino a c i d s such as l y s i n e , m e t h i o n i n e , h i s t i d i n e , and c y s t e i n e (79; u n p u b l . d a t a ) .


12.

DUFFEY AND FELTON

Table I I .

The R e l a t i o n s h i p Between the N u t r i t i v e V a l u e o f V a r i o u s P r o t e i n s , as Indexed by R e l a t i v e Growth R a t e , t o L a r v a l Spodoptera e x i g u a and H e l i o t h i s zea as a F u n c t i o n o f A l k y l a t a b l e Amino A c i d s

Dietary protein



T o t a l AAA (/unoles/lOO gm o f d i e t )

% Reduction of R e l . Growth Rate (mg/dav/me l a r v a )

S. e x i g u a H. zea 10 10 Casein 895 50 20 Soy 565 73 35 Tomato 482 80 50 Glutein 292 99 90 Zein 238 % R e l a t i v e growth based on u n t r e a t e d c a s e i n as 100%: Total AAAtotal μπιοίβε o f a l k y l a t a b l e amino a c i d s (lysine, histidine, m e t h i o n i n e , and c y s t e i n e ) per 100 gm o f d i e t : D i e t a r y p r o t e i n s a t 1.0%; p r o t e i n a l k y l a t e d w i t h 3.5 mM c h l o r o g e n i c a c i d / k g d i e t wwt.

The a b i l i t y of chlorogenoquinone to render p r o t e i n l e s s n u t r i t i o u s i s not p e c u l i a r t o c a s e i n , b u t g e n e r a l i z a b l e t o a v a r i e t y o f p l a n t p r o t e i n s . Hence, the e f f i c a c y o f such an o x i d a t i v e defense w i l l i n p a r t be dependent upon the q u a l i t y o f p l a n t p r o t e i n as i n d e x e d by the q u a n t i t y o f a l k y l a t a b l e groups. A l s o , the e f f i c a c y o f t h i s defense w i l l a l s o be c o n t i n g e n t upon the a b s o l u t e l e v e l s o f p r o t e i n . The h i g h e r the d i e t a r y l e v e l o f p r o t e i n (e.g., c a s e i n ) , the g r e a t e r the a l l e v i a t i o n o f the a n t i n u t r i t i v e e f f e c t o f c h l o r o g e n o q u i n o n e (Table I I I ) . T h i s e f f e c t i s not r e s t r i c t e d t o c a s e i n ; s i m i l a r r e s u l t s are o b t a i n e d w i t h soy p r o t e i n and tomato p r o t e i n i n p r o p o r t i o n t o the number o f AAA'a (unpubl. d a t a ) . The a l l e v i a t i o n o c c u r s because the r e l a t i v e number o f a l k y l a t a b l e groups exceeds that destroyed by the equivalents of c h l o r o g e n o q u i n o n e . The most n u t r i t i o u s p r o t e i n s are the best a l l e v i a t o r s o f t h i s a n t i n u t r i t i v e e f f e c t (124). T h e r e f o r e , the e f f i c a c y o f such a defense w i l l depend b o t h upon q u a l i t y and q u a n t i t y o f p r o t e i n , as w e l l as the r e l a t i v e q u a n t i t y o f o x i d i z a b l e phenolics. P l a n t phenology may have a g r e a t bearing on the magnitude o f the a n t i n u t r i t i v e e f f e c t (79,124,125).

Table I I I .

Protein

Casein

See

E f f e c t o f Q u a n t i t y o f P r o t e i n on Quinone-mediated Depreciation of N u t r i t i v e Q u a l i t y of Dietary P r o t e i r Q u a l i t y f o r l a r v a l S. e x i g u a

% i n Diet (wet wt.)

0.5 1.0 2.0 4.0 legend of Table I I .

T o t a l AAA (μπιοΙββ/ΙΟΟ gm d i e t ) 448 895 1790 3580

% R e l a t i v e Growth (mg/day/mg l a r v a ) 75 82 90 90


175

176



The l e v e l s o f PPO i n f o l i a g e ( a t immature g r e e n f r u i t s t a g e ) o f the tomato p l a n t are s t r o n g l y n e g a t i v e l y c o r r e l a t e d ( r - - 0.72, ρ > 0.001, η - 75) w i t h the a b i l i t y o f H. zea t o grow on f o l i a g e . A l s o , f o l i a r PPO a c t i v i t y i n c r e a s e s w i t h age, w h i c h i s a l s o s t r o n g l y n e g a t i v e l y c o r r e l a t e d w i t h a reduced a b i l i t y o f l a r v a l H. zea t o grow (79; u n p u b l . d a t a ) . I n a d d i t i o n , i t has been shown t h a t p l a n t PPO a c t i v i t y p e r s i s t s i n t h e i n s e c t ' s g u t hours after i n g e s t i o n , and i n f a c t t h e i n s e c t ' s d i g e s t i v e p r o c e s s e s actually a c t i v a t e PPO b y 50% w i t h i n minutes a f t e r i n g e s t i o n ( 7 9 ) . Because up t o 50% o f i n g e s t e d c h l o r o g e n i c a c i d i s c o v a l e n t l y bound t o p l a n t p r o t e i n (the cause o f a s i g n i f i c a n t l o s s o f amino a c i d s ; e.g., up t o 38% o f l y s i n e and c y s t e i n e , and 10-20% o f h i s t i d i n e ) when t h e i n s e c t feeds on f o l i a g e , i t i s c o n c l u d e d t h a t PPO i s o p e r a t i n g as a s t r o n g a n t i n u t r i t i v e defense a g a i n s t these i n s e c t s . A l t h o u g h PPO i s t h e major p h e n o l a s e o f t h e tomato p l a n t , p e r o x i d a s e (POD) a l s o i s p r e s e n t ( 7 9 ) . A major l i m i t a t i o n o f t h e use o f POD as a defense i s t h a t , u n l i k e PPO, i t r e q u i r e s a continuous source o f H2O2 i n o r d e r t o o x i d i z e p h e n o l i c s . One p o s s i b l e advantage o f POD i s t h a t i t i s a b l e t o o x i d i z e a g r e a t e r v a r i e t y o f p h e n o l i c s . F o l i a r PPO h a s s i g n i f i c a n t a c t i v i t y w i t h c a f f e i c a c i d and c h l o r o g e n i c a c i d ; whereas, POD can o x i d i z e a much g r e a t e r v a r i e t y o f s u b s t r a t e s (e.g., c h l o r o g e n i c a c i d , c a f f e i c a c i d , r u t i n , e s c u l e t i n , f e r u l i c a c i d , t y r o s i n e , and coumaric a c i d ) . Moreover, POD c a n a t t a c k p r o t e i n b y o x i d i z i n g t y r o s i n y l and s u l p h y d r y l m o i e t i e s , as w e l l as d e a m i n a t i n g and d e c a r b o x y l a t i n g amino a c i d s such as l y s i n e . As p o i n t e d out b e f o r e , these r e a c t i o n s are v e r y d e t r i m e n t a l t o p r o t e i n i n t e g r i t y . Thus, t h i s greater spectrum o f a c t i v i t y may make POD a s t r o n g o r i n d i s p e n s i b l e component o f enzyme-based defense. To t h i s p o i n t our work w i t h POD i s l i m i t e d . A d d i t i o n o f POD w i t h c h l o r o g e n i c a c i d o r r u t i n t o a r t i f i c i a l d i e t s t r o n g l y reduces the n u t r i t i v e v a l u e o f d i e t a r y c a s e i n f o r l a r v a l H. zea (Table I V ) . This again i s i n part the r e s u l t o f covalent binding o f the o x i d i z e d p h e n o l i c t o the p r o t e i n . Our major e v i d e n c e f o r the a n t i n u t r i t i v e a c t i o n o f POD comes from f e e d i n g e x p e r i m e n t s w i t h f o l i a g e i n w h i c h c a t a l a s e was added t o macerated f o l i a g e . C a t a l a s e c o n v e r t s H2O2 (needed b y POD) t o w a t e r ; hence, t h e presence o f h i g h c a t a l a s e a c t i v i t y i n f o l i a g e reduced the impact o f POD on f o o d q u a l i t y . The a d d i t i o n o f c a t a l a s e t o f o l i a g e n o t o n l y reduced the l e v e l o f POD a c t i v i t y i n f r e s h l y c r u s h e d t i s s u e 3 6 - f o l d b u t c o r r e s p o n d i n g l y improved t h e r e l a t i v e growth o f l a r v a l H. zea by 0.042 mg/day/mg l a r v a (Table V ) . T h i s e v i d e n c e i m p l i c a t e s POD as a p o t e n t i a l l y i m p o r t a n t factor i n r e d u c i n g t h e growth o f H. zea. However, because t h e i n s e c t ' s g u t c o n t e n t c o n t a i n s h i g h l e v e l s o f c a t a l a s e , the a n t i b i o t i c a c t i o n o f POD may be l i m i t e d . I n c o n t r a s t , PPO does n o t r e q u i r e H 0 and remains h i g h l y a c t i v e i n the i n s e c t ' s g u t d u r i n g the d i g e s t i o n o f f o o d and even remains a c t i v e i n the f a e c e s . 2


2

12.

DUFFEY AND FELTON


T a b l e IV.


E f f e c t o f O x i d a t i v e Enzyme A c t i v i t y on t h e Growth o f l a r v a l H e l i o t h i s zea

Treatment % R e l a t i v e Growth P r o t e i n alone 100a (tomato f o l i a r p r o t e i n a t 0.5%) Protein + 3.5 mM l i n o l e i c a c i d 100a Protein + 3.5 mM c h l o r o g e n i c a c i d 102a Protein + lOmM H 0 105a Protein + lipoxygenase + 3.5 mM l i n o l e i c a c i d 48.1b Protein + p e r o x i d a s e + H 0 (lOmM) + 7.0 mM c h l o r o g e n i c a c i d 27.1c Protein + p e r o x i d a s e + H 0 (lOmM) + 7.0 mM r u t i n 78.Od Protein + polyphenol oxidase + 7.0 mM c h l o r o g e n i c a c i d 32 .0c R e l a t i v e growth - mg/day/mg o f l a r v a : l i p o x y g e n a s e , p e r o x i d a s e , and p o l y p h e n o l o x i d a s e were added t o d i e t a t a c t i v i t i e s c o r r e s p o n d i n g t o t h a t found i n tomato f o l i a g e : r u t i n and c h l o r o g e n i c a c i d a t 3.5 mM/kg d i e t wwt. S i g n i f i c a n t d i f f e r e n c e s between means w i t h i n a column, based 95% c o n f i d e n c e i n t e r v a l s from ANOVA, a r e shown by d i f f e r e n t l e t t e r s . PPO - 0.100 O.D./min/gm d i e t wwt.; POD - 27.0 O.D./min/gm d i e t wwt. 2

2

2

2

2

2


177


178 T a b l e V.

E f f e c t o f Exogenous C a t a l a s e on L a r v a l Growth and F o l i a r Oxidative A c t i v i t i e s

Treatment

CAT-L

C a t a l a s e added

3570a

No c a t a l a s e added

lib

P0D

2

RGR

3

1.85a

0.296

65.20b

0.254


1

CAT - c a t a l a s e a c t i v i t y i n units/min/gm f o l i a g e 2 POD - p e r o x i d a s e a c t i v i t y i n OD470/min/gm f o l i a g e 3 R G R - r e l a t i v e l a r v a l growth r a t e (mg/day/mg l a r v a ) . S i g n i f i c a n t d i f f e r e n c e s between means w i t h i n a column, b a s e d 95% c o n f i d e n c e i n t e r v a l s from ANOVA, a r e shown by d i f f e r e n t l e t t e r s .

We have t h e l e a s t i n f o r m a t i o n about t h e a n t i n u t r i t i v e e f f e c t s of lipoxygenase (LOX). Experiments (Table I V ) show t h a t t h e n u t r i t i v e v a l u e o f p r o t e i n t o H. z e a i s reduced by t r e a t m e n t w i t h LOX and l i n o l e i c a c i d ( 5 2 % r e d u c t i o n i n growth). Tomato f o l i a g e c o n t a i n s s i g n i f i c a n t q u a n t i t i e s o f LOX a c t i v i t y and l i n o l e i c a c i d has been shown t o be c o v a l e n t l y bound t o p r o t e i n b o t h i n v i t r o and i n p l a n t a (unpubl. d a t a ) . S t u d i e s a r e underway t o determine w h i c h amino a c i d s a r e p r e f e r e n t i a l l y d e s t r o y e d . A l s o , p r e l i m i n a r y s t u d i e s w i t h f o l i a g e demonstrate t h a t c o p i o u s q u a n t i t i e s o f m a l o n d i a l d e h y d e are g e n e r a t e d i n c r u s h e d f o l i a g e ; t h e a n t i n u t r i t i o n a l e f f e c t s o f t h i s S c h i f f base former a r e as y e t undetermined. C u r r e n t l y we a r e d e t e r m i n i n g i f t h e j o i n t a n t i n u t r i t i o n a l e f f e c t s o f POP, POD, and LOX a c t i v i t y a r e a d d i t i v e o r s y n e r g i s t i c . I f these a c t i v i t i e s a r e found t o d i f f e r e n t i a l l y d e s t r o y amino a c i d s , t h e n t h e i r b a t t e r y o f e f f e c t s may be s y n e r g i s t i c . I f t h e i r e f f e c t s a r e e q u a l (same amino a c i d s d e s t r o y e d ) , t h e n perhaps o n l y one enzyme, s a y PPO (with high phenolic levels) requires a m p l i f i c a t i o n t o prove a s u f f i c i e n t a n t i n u t r i t i v e d e f e n s e . We a r e a l s o determining i f v a r i o u s o x i d i z e d phenolics (e.g., c a f f e i c a c i d , c h l o r o g e n i c a c i d , coumaric a c i d , and r u t i n ) a r e e q u i v a l e n t i n t h e i r a b i l i t y t o a l k y l a t e and i m p a i r p r o t e i n q u a l i t y . A b r e e d i n g program t o enhance r e s i s t a n c e would b e n e f i t from the knowledge o f w h i c h enzymes and/or s u b s t r a t e s t o enhance. Our s u r v e y s o f w i l d s p e c i e s o f h v c o p e r s i c o n show t h a t c e r t a i n genotypes ( p a r t i c u l a r l y L. h i r s u t u m f . glabratum) n o t o n l y have h i g h e r constitutive levels of catecholic phenolics t h a n found i n L. e s c u l e n t u m b u t a l s o h i g h e r l e v e l s o f PPO, POD, and LOX (99; u n p u b l . data). I n d u c t i o n o f Enzymes by Feeding-Damage. A l t h o u g h t h e tomato p l a n t has c o n s t i t u t i v e l e v e l s o f PPO, POD, and LOX, t h e d e f e n s i v e a b i l i t y o f t h e p l a n t may be enhanced i f these enzymes were i n d u c e d by i n s e c t f e e d i n g damage. The i n d u c i b l e n a t u r e o f PPO, POD, and p h e n o l i c s as a r e s u l t o f i n f e c t i o n by m i c r o o r g a n i s m s has a l r e a d y been d i s c u s s e d . S i m i l a r l y , t h e i n d u c t i o n o f P i ' s by n o c t u i d l a r v a e has been p o i n t e d out. Indeed, f e e d i n g damage by l a r v a l H. z e a i s a b l e t o s y s t e m i c a l l y induce v e r y h i g h l e v e l s o f PPO a c t i v i t y i n


12.

DUFFEY AND FELTON

Enzymatic Antinutritive Defenses of Tomato 179

tomato f o l i a g e 24 hours a f t e r damage ( T a b l e V I ) . I n d u c t i o n o f POD and LOX by H. zea was n o t observed. I n c o n t r a s t , the Tomato R u s s e t m i t e A c u l o p s l y c o p e r s i c i d r a m a t i c a l l y i n d u c e d LOX and POD levels ( T a b l e V I ) . We have n o t y e t r e l a t e d the i n d u c t i o n o f t h e s e enzymes t o the l e v e l s o f p h e n o l s , p r o t e i n , and/or i n s e c t performance on i n d u c e d v e r s u s uninduced f o l i a g e .

Table VI.

I n d u c t i o n o f Tomato P l a n t F o l i a r O x i d a t i v e Enzymes by A r t h r o p o d s


%Relative A c t i v i t v

Russet M i t e

Enzyme

H.

Lipoxygenase

105

2367

Peroxidase

100

264

980

96

Polyphenol

Oxidase

zea

2

1

3

undamaged p l a n t s r e p r e s e n t 100% a c t i v i t y ; represents systemic i n d u c t i o n (other leaves); represents l o c a l i z e d induction (within a l e a f ) .

Impact o f O x i d a t i v e Enzymes on A p h i d s . Tomato p l a n t s a r e a l s o a t t a c k e d by a v a r i e t y o f o t h e r a r t h r o p o d s such as w h i t e f l i e s , m i t e s , and a p h i d s (126,127). Trichomes have been s t u d i e d as a b a s i s o f r e s i s t a n c e a g a i n s t many o f these a r t h r o p o d s ( 9 9 ) . A c o n s i s t e n t feature o f r e s i s t a n c e has been the a l l u s i o n t o the sticky e n t r a p p i n g p r o p e r t i e s o f t r i c h o m e s ( t y p e V I ) . We have shown t h a t these entrapping properties result from the presence of c o m p a r t m e n t a l i z e d c a t e c h o l i c p h e n o l i c s and PPO/POD i n the t i p s o f type V I t r i c h o m e s (99: u n p u b l . d a t a ) , w h i c h upon breakage, f o r example by a p h i d s , l e a d t o quinone mediated p o l y m e r i z a t i o n o f t r i c h o m a l p r o t e i n . T h i s p o l y m e r i z e d p r o t e i n forms the c l a s s i c a l b l a c k e n e d b o o t s on a p h i d ' s f e e t . U t i l i z i n g a s e r i e s o f c r o s s e s between PI 134417 and W a l t e r [the p a r e n t s i n Kennedy's s t u d i e s -of 2-tridecanone resistance ( 1 2 8 ) ] , we have shown a significant n e g a t i v e c o r r e l a t i o n between the number o f a p h i d s , Macrosiphon e u p h o r b i a e . per l e a f l e t and the d e n s i t y o f type V I t r i c h o m e s and t h e i r phenolase a c t i v i t y . These f i n d i n g s p a r a l l e l the s t u d i e s o f T i n g e y ' s group on r e s i s t a n c e i n p o t a t o (see c h a p t e r i n t h i s volume). As mentioned above, c e r t a i n a c c e s s i o n s o f L. h i r s u t u m f . g l a b r a t u m a r e s o u r c e s o f h i g h l e v e l s o f f o l i a r p h e n o l i c s and o x i d a t i v e enzymes. Some o f the same a c c e s s i o n s o f L. h i r s u t u m f . g l a b r a t u m have been shown t o be h i g h e s t i n type V I t r i c h o m a l d e n s i t i e s w i t h commensurately h i g h t r i c h o m a l PPO/POD a c t i v i t y . Hence, i t s h o u l d be p o s s i b l e , by employing o x i d a t i v e enzymes, t o b r e e d f o r s i m u l t a n e o u s r e s i s t a n c e a g a i n s t p e s t s such as a p h i d s , H. zea and S. e x i g u a .


180



P o t e n t i a l I n c o m p a t i b i l i t y with Proteinase I n h i b i t o r s I t was suggested e a r l i e r t h a t P i ' s and PPO might s e r v e as complementary defenses because o f the demand they p l a c e upon the i n s e c t f o r s u l p h u r amino a c i d s . U n f o r t u n a t e l y , the two types o f d e f e n s e s may be i n c o m p a t i b l e . P i ' s a r e p o l y p e p t i d e s (8,000 - 40,000 mw) w h i c h have a v a r i e t y o f a l k y l a t a b l e amino a c i d s (e.g., c y s t e i n e - c y s t e i n e and l y s i n e ) . P i ' s o f t e n have l y s i n e n e a r the a c t i v e s i t e , and many P i ' s have m u l t i p l e d i s u l p h i d e bonds w h i c h are i n t e g r a l f o r a c t i v i t y (129-131). D e r i v a t i z a t i o n o f these amino a c i d s by quinones s h o u l d render P i ' s l e s s a c t i v e . Indeed, t h i s has been shown t o o c c u r b o t h i n v i t r o and i n p l a n t a (125). Treatment o f soybean t r y p s i n i n h i b i t o r ( I I ) , tomato PI ( I and I I ) , and l i m a bean i n h i b i t o r w i t h PPO and c h l o r o g e n i c a c i d i n v i t r o caused a l o s s o f ability to inhibit bovine trypsin: this loss of activity c o r r e s p o n d e d t o a l o s s o f up t o 30% o f d e t e c t a b l e amino a c i d s such as l y s i n e and c y s t e i n e as a r e s u l t o f a l k y l a t i o n . Furthermore, i t was shown the a c t i o n o f PPO p l u s c h l o r o g e n i c a c i d a g a i n s t P i ' s I and I I i n tomato f o l i a g e r e s u l t e d i n up t o 70% l o s s i n t h e i r d e t e c t a b i l i t y by immunological a s s a y w i t h a c o r r e s p o n d i n g 50% l o s s i n the a b i l i t y o f f o l i a g e t o i n h i b i t the growth o f S. e x i g u a . The l o s s o f PI i d e n t i t y and b i o l o g i c a l a c t i v i t y was magnified by wounding (124,125). Crop p l a n t s c o n t a i n a v a r i e t y o f p o t e n t i a l a l k y l a t i n g o r S c h i f f base f o r m i n g agents (e.g., g o s s y p o l , i s o t h i o c y a n a t e from mustard o i l s , "CN from c y a n o g e n s i s , DIMBOA, e p o x i d e s , sesquiterpene l a c t o n e s , o x i d i z e d t a n n i n s , and a l d e h y d e s ) w h i c h are i m p l i c a t e d as d e f e n s e s a g a i n s t i n s e c t s and pathogens. These a l k y l a t i n g agents a l s o have the a b i l i t y t o s i g n i f i c a n t l y reduce ( g e n e r a l l y 30-70%) the i n h i b i t o r y p r o p e r t i e s o f a v a r i e t y o f P i ' s ( e . g . , K u n i t z and Bowman-Birk i n h i b i t o r s , tomato PI I and I I , p o t a t o i n h i b i t o r I and I I ) . G e n e r a l l y , PPO and POD w i t h a v a r i e t y o f s u b s t r a t e s (e.g., c a f f e i c a c i d , c h l o r o g e n i c a c i d , coumaric a c i d , and e s c u l e t i n ) were the most e f f e c t i v e a t i n a c t i v a t i n g P i ' s compared t o e p o x i d e s and S c h i f f base formers. Some s e l e c t e d r e s u l t s are shown i n T a b l e V I I . Tomato PI I I was more r e s i s t a n t t o i n a c t i v a t i o n t h a n s e v e r a l o t h e r P i ' s (unpubl. d a t a ) , w h i c h s u g g e s t s t h a t c h e m i c a l i n c o m p a t i b i l i t i e s i n t r a n s g e n i c p l a n t s may be p a r t i a l l y a v o i d e d by the c o r r e c t c h o i c e o f P I . I n v i e w o f the r e c e n t emphasis on t r a n s g e n i c a l t e r a t i o n o f crop p l a n t s w i t h PI genes (119-122,132), our r e s u l t s suggest t h a t u n l e s s the c h e m i c a l m i l i e u o f the r e c e i v i n g p l a n t i s p r o p e r l y a c c o u n t e d f o r the e f f i c a c y o f P i ' s as a b a s i s o f r e s i s t a n c e may be compromised.

P o t e n t i a l Incompatibilités w i t h B i o l o g i c a l C o n t r o l Agents A n o t h e r p o t e n t i a l c o n s t r a i n t upon the use o f o x i d a t i v e enzymes as bases of host plant resistance may be their potential incompatibility with b i o l o g i c a l c o n t r o l agents. Tomato plant p h e n o l i c s ( r u t i n and c h l o r o g e n i c a c i d ) have been shown t o be


12.

DUFFEY AND FELTON Table V I I .


Impact o f S e l e c t e d P l a n t N a t u r a l P r o d u c t s upon P r o t e i n a s e I n h i b i t o r A c t i v i t y a g a i n s t Bovine Trypsin 1

C h e m i c a l Treatment Allylisothiocyanate

Inhibitor % Inactivation 32 STI 0 Tomato PI I I DIMBOA 49 STI Gossypol 5 STI 64 Tomato PI I Tannic a c i d 50 STI 74 T a n n i c a c i d + H o 0 + POD STI L i p o x y g e n a s e + l i n o l e i c a c i d STI 33 47 Tomato PI I 20 Tomato PI I I POD + H 0 + coumaric a c i d 53 STI 75 Tomato PI I 12 Tomato PI I I Data d e r i v e d from Workman, F e l t o n , and D u f f e y , u n p u b l . d a t a : % I n a c t i v a t i o n i s d e t e r m i n e d by comparing a b i l i t y o f u n t r e a t e d PI versus p r e t r e a t e d proteinase i n h i b i t o r to i n h i b i t bovine t r y p s i n h y d r o l y s i s o f TAME i n v i t r o : f o r treatment a l l c h e m i c a l s were used a t 3.5 mM: STI - soy t r y p s i n i n h i b i t o r I ; POD - p e r o x i d a s e :


2

2

2

1

m o d e r a t e l y s a f e compared t o t o m a t i n e i n t h e i r d e t r i m e n t a l e f f e c t s upon the ichneumonid p a r a s i t o i d Hyposoter e x i g u a e (32,97). The e f f e c t s o f p h e n o l i c s i n c o n j u n c t i o n w i t h PPO and POD upon t h i s p a r a s i t o i d are unknown. T h e i r a c t i o n may be i n c o m p a t i b l e i f the growth o f the h o s t l a r v a e were s u f f i c i e n t l y r e s t r i c t e d so as t o i m p a i r the growth o f the p a r a s i t o i d ( 9 7 ) . The use o f h i g h t r i c h o m a l d e n s i t y i n c o n j u n c t i o n w i t h h i g h t r i c h o m a l PPO a c t i v i t y t o c o n t r o l a p h i d s may compromise the e f f i c a c y o f such p a r a s i t o i d s . I t i s not known i f h i g h t r i c h o m a l d e n s i t y / h i g h trichome PPO activity is c l o s e l y g e n e t i c a l l y l i n k e d w i t h the p r o d u c t i o n o f 2 - t r i d e c a n o n e i n L y c o p e r s i c o n h i r s u t u m f . glabratum. Kennedy's group has found t h a t the p r e s e n c e o f 2 - t r i d e c a n o n e i n trichomes t o be i n c o m p a t i b l e w i t h the a c t i o n o f the p a r a s i t o i d Campoletis s o n o r e n s i s a g a i n s t H. zea (98). I n the absence o f PPO, r u t i n and c h l o r o g e n i c a c i d i n h i b i t the r e p l i c a t i o n o f a n u c l e a r p o l y h e d r o s i s AcMNPV i n i n s e c t t i s s u e c u l t u r e ( T r i c o p l u s i a n i ) . These c h e m i c a l s i n a r t i f i c i a l d i e t a l s o s t r o n g l y reduced the i n f e c t i v i t y o f HzSNPV i n H. zea (133). I n the p r e s e n c e o f PPO and c h l o r o g e n i c a c i d , the s o l u b i l i t y o f the o c c l u s i o n body o f HzSNPV i s markedly reduced, and c o r r e s p o n d i n g l y , i n f e c t i v i t y i n l a r v a l H. zea i s reduced up to 90% (124,134). Such a n e g a t i v e impact upon the v i r u s a r i s e s from a l k y l a t i o n o f p o l y h e d r o n p r o t e i n s by c h l o r o g e n o q u i n o n e . Hence, r e s i s t a n c e b a s e d on PPO and POD may s e v e r e l y compromise the e f f i c a c y o f v i r a l c o n t r o l agents i n


181


182

the f i e l d . Furthermore, i f i n s e c t v i r u s e s a r e t o be used as v e c t o r s o f a l i e n genes ( e . g . , n e u r o p e p t i d e s o r enzymes; 132,135-137), c o n s i d e r a t i o n must be g i v e n t o t h e p o t e n t i a l o f such o x i d a t i v e enzymes t o d e t r a c t from c o n t r o l . S u p r i z i n g l y , l i p i d h y d r o p e r o x i d e s produced from t h e a c t i o n o f LOX on l i n o l e i c a c i d enhanced t h e i n f e c t i v i t y o f HzSNPV i n zea (unpubl. data; Table V I I I ) . I n a d d i t i o n , i t has been found t h a t t h e t o x i c i t y o f p u r i f i e d t o x i n from B a c i l l u s t h u r i n g i e n s i s k u r s t a k i i s enhanced up t o 50% by a l k y l a t i o n with c h l o r o g e n o q u i n o n e (Ludlum, F e l t o n , and D u f f e y , u n p u b l . d a t a ) ( T a b l e . V I I I ) . Other c h e m i c a l s such as P I from soybean and t o m a t i n e a l s o enhanced t h e a c t i v i t y o f b o t h NPV and BTk a g a i n s t H. z e a ( T a b l e V I I I ) .


Table V I I I .

E f f e c t o f P h y t o c h e m i c a l s on the I n f e c t i v i t y o f NPV and BTK i n H e l i o t h i s z e a

Mortality 2

Ratio 3

Treatment

NPV

STI

1..34a

1.,21a

CHA

0. ,74a

1.,68b 2. 76c

CHA

+ PPO

0. ,50b

LOX

+ linolenic acid

2.,60c

Rutin

0. ,53b

Tomatine

1.,61d

BTK

1

1.,22a

STI - soy t r y p s i n i n h i b i t o r I i n d i e t a t 0.18% wwt; CHA c h l o r o g e n i c a c i d i n d i e t a t 3.5 mM/kg d i e t wwt; r u t i n a t 3.5 mM/kg d i e t wwt; t o m a t i n e a t 0.9 mM/kg d i e t wwt.: NPN - HzSnPV; LOX - l i p o x y g e n a s e ; PPO - p o l y p h e n o l o x i d a s e : m o r t a l i t y r a t i o - % m o r t a l i t y i n treatment d i e t / m o r t a l i t y i n control diet. R a t i o 1.0 shows enhancement o f i n f e c t i v i t y : , F i x e d dose o f pathogen such t h a t l a r v a e i n g e s t i n g c o n t r o l d i e t s u f f e r e d 40-50% m o r t a l i t y . S i g n i f i c a n t d i f f e r e n c e s between means w i t h i n a column, based on 95% c o n f i d e n c e i n t e r v a l s from ANOVA, a r e shown b y d i f f e r e n t l e t t e r s . 1

2

3

C r i t i c a l C o m p l i c a t i o n s i n the Use o f O x i d a t i v e Resistance a g a i n s t Noctuid Larvae

Enzymes as Bases o f

Our knowledge o f how t o most e f f e c t i v e l y u t i l i z e PPO, POD, and LOX as a n t i n u t r i t i v e bases o f r e s i s t a n c e a g a i n s t n o c t u i d larvae i s i n s u f f i c i e n t . A number o f o t h e r c r i t i c a l enzymatic and c h e m i c a l


12.

DUFFEY AND FELTON

Enzymatic Antinutritive Defenses ofTomato

r e a c t i o n s o c c u r i n b o t h wounded p l a n t t i s s u e and t h e i n s e c t s ' d i g e s t i v e f l u i d s t h a t might s t r o n g l y modulate t h e o v e r a l l e f f e c t . PPO has h i g h a c t i v i t y over a b r o a d pH range (5.5 - 10.0) and e f f i c i e n t l y oxidizes a variety of caffeic acid derivatives to quinones w i t h o u t r e q u i r i n g a c o f a c t o r . PPO i s o p e r a t i o n a l t h r o u g h a l l phases o f d i g e s t i o n . I n comparison t o POD, t h e use o f PPO f o r r e s i s t a n c e i s r e l a t i v e l y s t r a i g h t f o r w a r d . A l t h o u g h POD a l s o has h i g h a c t i v i t y over a b r o a d pH range, i t s f u l l a c t i v i t y i s compromised by t h e f a c t t h a t i t r e q u i r e s H 0 as a c o f a c t o r . A l t h o u g h p l a n t s a r e known t o produce a l o c a l i z e d b u r s t o f H 0 a t s i t e s o f damage ( 3 6 ) , i t i s n o t known i n t h e tomato system i f t h i s burst provides sufficient H 0 to f a c i l i t a t e degradation of p r o t e i n q u a l i t y d u r i n g t h e e a r l y s t a g e s o f f e e d i n g . Both f o l i a g e , i n s e c t r e g u r g i t a t e , midgut t i s s u e s and lumen c o n t e n t s a l l c o n t a i n catalase. In fact, t h e r e g u r g i t a t e a l o n e o f l a r v a l H. z e a s i g n i f i c a n t l y impedes p l a n t POD a c t i v i t y because o f t h e p r e s e n c e o f h i g h c a t a l a s e a c t i v i t y ( F i g u r e 3 ) . We have a l r e a d y provided e v i d e n c e t h a t a d d i t i o n o f c a t a l a s e t o c r u s h e d f o l i a g e enhances t h e a b i l i t y o f H. z e a t o grow on t h a t f o l i a g e (Table I V ) , presumably through r e d u c t i o n o f endogenous l e v e l s o f p l a n t H 0 with consequent d i m i n u t i o n o f POD a c t i v i t y . However, i n o r d e r t o f o r m a l l y e s t a b l i s h the defensive r o l e o f p l a n t POD, one must u n d e r s t a n d i t s r e l a t i o n s h i p n o t o n l y w i t h p l a n t and i n s e c t d e r i v e d c a t a l a s e , b u t a l s o w i t h o t h e r c h e m i c a l and e n z y m a t i c systems t h a t degrade o r g e n e r a t e H 0 . For example, b o t h f o l i a g e and t h e i n s e c t ' s g u t f l u i d c o n t a i n s u p e r o x i d e dismutase (SOD), an enzyme w h i c h c o n v e r t s s u p e r o x i d e i o n s (Of) t o H 0 ( F i g u r e 3) . The f o r m a t i o n o f s u p e r o x i d e i o n i s f a v o r e d i n b a s i c c o n d i t i o n s (52,138,139), and i s a l s o a b y - p r o d u c t o f semiquinone a c t i o n on 0 (73) and o f a u t o x i d a t i v e r e a c t i o n s (e.g., catecholic phenolics, t h i o l s , and l e u k o f l a v a n s ) (139). A l s o , c e r t a i n enzymes produce O^F or K 0 as end p r o d u c t s (Table I X ) . Hence, t h e c o u n t e r - b a l a n c i n g a c t i v i t i e s o f c a t a l a s e and SOD i n t h e g e n e r a t i o n o f H 0 i n t h e p l a n t and t h e i n s e c t must a l s o be a c c o u n t e d f o r i n o r d e r t o a s s e s s t h e e f f i c a c y o f POD as a p l a n t defense. H 0 c a n a l s o be g e n e r a t e d n o n - e n z y m a t i c a l l y from coo x i d a t i v e p r o c e s s e s ( F i g u r e 3) such as v i a t h e o x i d a t i o n o f a c a t e c h o l i c p h e n o l i c by an o-quinone (139-143). Quinone f o r m a t i o n can be t h e r e s u l t o f PPO a c t i v i t y , b u t a l s o c a n a r i s e from spontaneous o x i d a t i o n i n b a s i c media (142,143). A l t h o u g h we have e s t a b l i s h e d i n v i t r o t h a t c h l o r o g e n i c a c i d and c a f f e i c a c i d c a n g e n e r a t e s i g n i f i c a n t q u a n t i t i e s o f H 0 , we have n o t e s t a b l i s h e d whether t h i s p r o c e s s o c c u r s i n c r u s h e d f o l i a g e and/or t h e i n s e c t ' s gut and s i m u l t a n e o u s l y f u r n i s h e s s u f f i c i e n t H 0 t o p e r m i t POD t o o p e r a t e d u r i n g t h e d i g e s t i o n o f food. I t a l s o remains t o be d e t e r m i n e d whether c e r t a i n p h e n o l i c s (e.g., r u t i n , v s c h l o r o g e n i c acid, vs. c a f f e i c acid) a r e more e f f i c i e n t than others a t g e n e r a t i n g H 0 . A l s o , c e r t a i n enzymes p r e s e n t i n p l a n t f o l i a g e ( e . g . , c a t a l a s e , and a s c o r b i c a c i d p e r o x i d a s e ; 144-146) c o u n t e r a c t the p r o d u c t i o n o f H 0 by r e d u c i n g i t t o water ( F i g u r e 3 ) . I t may be p o s s i b l e t o b r e e d f o r t h e a p p r o p r i a t e e n z y m a t i c and c h e m i c a l m i l i e u w h i c h w i l l f a v o r a h i g h e r p r e - i n j u r y l e v e l o f H 0 production, a more r a p i d post-damage b u r s t , and/or i t s maintenance d u r i n g f e e d i n g by t h e i n s e c t , t h e r e b y p e r m i t t i n g t h e 2

2

2


2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2


2

2

183


184


2H0

2Η Ο

Figure 3. Interrelationship of Oxidative and Reductive Processes Linked t o t h e P r o d u c t i o n o f o-Quinones. POD — p e r o x i d a s e , PPO = p o l y p h e n o l o x i d a s e , GSG - g l u t a t h i o n e , GSSG oxidized glutathione.


12.

DUFFEY AND FELTON


j o i n t a n t i n u t r i t i v e a c t i o n o f PPO and POD. The s i m u l t a n e o u s use o f LOX may be c o m p l i c a t e d by the f a c t t h a t c a t e c h o l s such as r u t i n are known t o i n h i b i t LOX a c t i v i t y (147) as w e l l as scavenge f r e e r a d i c a l s g e n e r a t e d d u r i n g t h e s e o x i d a t i v e p r o c e s s e s (148). Other i n t e r a c t i v e f a c t o r s w h i c h w i l l d e t e r m i n e the a b i l i t y of oxidized phenolics (quinones and semiquinones) t o damage p r o t e i n are the l e v e l s o f a s c o r b i c a c i d , g l u t a t h i o n e , and o t h e r r e d u c t a n t s i n f o l i a g e and the i n s e c t ' s d i g e s t i v e system. The maintenance o f h i g h l e v e l s o f Η θ 2 , t o run POD, may be compromised by h i g h l e v e l s o f a s c o r b i c a c i d w h i c h can reduce Η θ 2 t o w a t e r ( 1 4 4 - 1 4 6 ) ( F i g u r e 3 ) . Furthermore, h i g h l e v e l s o f a s c o r b i c a c i d are a l s o c a p a b l e o f r e d u c i n g quinones t o p h e n o l i c s , w h i c h t h e n can counteract the antinutritive effects of quinone production ( F i g u r e s 1,2, & 3 ) . I n v i t r o . the p r e s e n c e o f a s c o r b i c acid i m p a i r s the p r o d u c t i o n o f c h l o r o g e n o q u i n o n e by PPO. However, t h i s c o u n t e r a c t i v e e f f e c t may be overcome by the enzyme a s c o r b i c a c i d o x i d a s e (AOX). w h i c h o x i d i z e s a s c o r b i c a c i d t o d e h y d r o a s c o r b i c a c i d . A d d i t i o n o f AOX to a r t i f i c i a l d i e t s c o n t a i n i n g ascorbic a c i d , c h l o r o g e n i c a c i d , and PPO causes a g r e a t e r r e d u c t i o n i n l a r v a l growth (unpubl. d a t a ) . Tomato f o l i a g e c o n t a i n s b o t h h i g h l e v e l s o f a s c o r b i c a c i d and AOX (60; unpubl. d a t a ) . Thus, i f one were to b r e e d f o r h i g h l e v e l s o f AOX, quinone p r o d u c t i o n would occur more rapidly because of lowered levels of the reductant/nutrient ascorbic a c i d (Figures 3 & 4). 2


2

T h i s multi-enzyme approach has s e v e r a l p o t e n t i a l advantages for c o n t r o l l i n g noctuid larvae. First, ascorbic acid is a n u t r i t i o n a l r e q u i r e m e n t f o r such l e p i d o p t e r a n s (27,30,149); i t s o x i d a t i o n t o d e h y d r o a s c o r b i c a c i d demands t h a t the i n s e c t use r e d u c i n g power i n the form o f g l u t a t h i o n e and NAD(P)H t o r e c l a i m a s c o r b i c a c i d . The s i m u l t a n e o u s p r o d u c t i o n o f quinones may also p l a c e a d r a i n on r e d u c i n g power because g l u t a t h i o n e i s r e a d i l y a l k y l a t e d by o-quinones (140,141; unpubl d a t a ) r e n d e r i n g it u n r e c l a i m a b l e . G l u t a t h i o n e may a l s o reduce o-quinones d i r e c t l y or w i t h an i n t e r v e n i n g s t e p i n v o l v i n g a s c o r b i c a c i d , t h e r e b y p l a c i n g a f u r t h e r d r a i n on reducing power ( F i g u r e 4). I f H2O2 i s d e t o x i f i e d by g l u t a t h i o n e p e r o x i d a s e a f u r t h e r d r a i n i s p l a c e d on r e d u c i n g power. G l u t a t h i o n e p e r o x i d a s e and g l u t a t h i o n e may a l s o be i n v o l v e d i n d e t o x i c a t i o n o f p r o d u c t s from l i p i d peroxidation r e s u l t i n g from LOX a c t i v i t y ( F i g u r e 3 ) . Reduced s u l p h u r amino a c i d i n t a k e as a r e s u l t o f the a c t i o n o f P i ' s o r quinones may may further exacerbate the requirement for reducing power and g l u t a t h i o n e . Hence, t h i s m u l t i p l e d r a i n may be o f s i g n i f i c a n c e i n c o n t r o l l i n g the i n s e c t i f h i g h l e v e l s o f r e d u c i n g power are r e q u i r e d to simulataneously d e t o x i f y o t h e r i n g e s t e d t o x i n s such i n s e c t i c i d e s or other n a t u r a l products. S i n c e P i ' s , PPO, POD, and LOX have the p o t e n t i a l t o i m p a i r s u l p h u r amino a c i d i n t a k e and u t i l i z a t i o n by t h e s e i n s e c t s , and such i n t a k e i s i m p o r t a n t f o r d e t o x i c a t i o n (e.g., g l u t a t h i o n e ) , i t may be p o s s i b l e t o c o n t r o l H. zea and S. e x i g u a not j u s t t h r o u g h a n t i n u t r i t i v e e f f e c t s but a l s o t h r o u g h impairment o f d e t o x i c a t i v e abilities. However, a deeper knowledge of these insects' d e t o x i c a t i v e a b i l i t i e s i s e s s e n t i a l i f t h e s e enzymes are t o be used s u c c e s s f u l l y . F u t h e r c o m p l i c a t i o n s arise, for like the f o l i a g e t h e y i n g e s t (146,148,150-153), t h e i r g u t s a l s o contain i n h e r e n t c a t a l a s e , s u p e r o x i d e dismutase, g l u t a t h i o n e p e r o x i d a s e ,



186


F i g u r e 4. Some I n t e r r e l a t i o n s h i p s Between Quinones, A s c o r b i c a c i d , G l u t a t h i o n e , and Reducing Power. The c y c l e o f redox events can o c c u r from l e f t t o r i g h t w i t h o u t i n t e r v e n t i o n o f enzymes. C e r t a i n enzymes c a n f a c i l i t a t e these r e a c t i o n s : 01 - p o l y p h e n o l o x i d a s e , 02 - p e r o x i d a s e , R l - quinone r e d u c t a s e without a s c o r b i c as a s u b s t r a t e , 03 — a s c o r b i c a c i d o x i d a s e , R2 — a s c o r b i c a c i d f r e e r a d i c a l r e d u c t a s e , R3 - d e h y d r o a s c o r b i c a c i d reductase, R4 - g l u t a t h i o n e r e d u c t a s e , R5 - g l u t a t h i o n e p e r o x i d a s e , LOOH - l i p i d h y d r o p e r o x i d e , and GS - c o v a l e n t l y bound g l u t a t h i o n e .


12.

DUFFEY AND FELTON



peroxidase, glutathione reductase, and other enzymes and r e d u c t a n t s (147,154-157). The consequences o f t h e b a l a n c e between the p l a n t d r i v e n c h e m i c a l and/or enzymatic r e a c t i o n s and those o f the i n s e c t a r e p o o r l y understood. A v a r i e t y o f p l a n t enzymes ( T a b l e I X ) generate t o x i c by-products. I t c e r t a i n l y may be p o s s i b l e t o simultaneously challenge the i n s e c t ' s a c q u i s i t i o n o f n u t r i e n t s , i t s b a l a n c e o f d e t o x i c a t i v e r e d u c i n g power, and i t s a b i l i t y t o h a n d l e t h e d i e t a r y and b o d i l y g e n e r a t i o n o f s u p e r o x i d e ions, hydroxyl ions, free radicals and H2O2 (52,139,147,154,155,158). The degree t o w h i c h t h e s e p l a n t f a c t o r s can be g e n e t i c a l l y m a n i p u l a t e d without i m p a i r i n g the p l a n t ' s p r o d u c t i v i t y , i s undetermined.

T a b l e IX.

Some O x i d a n t s and R e d u c t a n t s / A n t i o x i d a n t s i n P l a n t s

O x i d a n t s and By-products Aldehyde o x i d a s e ( s u p e r o x i d e i o n ) Glucose o x i d a s e ( s u p e r o x i d e i o n ) Xanthine oxidase (superoxide i o n ) Lipoxygenase ( h y d r o p e r o x i d e s , e p o x i d e s , free radicals) P o l y p h e n o l o x i d a s e (quinones)

Peroxidase

Re duc t a n t s/Ant i ox i d a n t s glutathione phenolics polyamines carotene s u p e r o x i d e dismutase glutathione p e r o x i d a s e and reductase catalase

(quinones, semiquinones free radicals) c h l o r o p h y l l ( i n dark) Chlorophyll ( i n light) vitamin Ε F l a v a n dehydrogenase ( s u p e r o x i d e i o n ) ascorbic acid Galactose oxidase (superoxide ion) 2°2 generators Superoxide dismutase Amine o x i d a s e Polyamine o x i d a s e G l y c o l a t e oxidase U r i c oxidase A u t o o x i d a t i o n and c o o x i d a t i o n of/by phenolics See r e f e r e n c e s 52,139,146,148,151,152,159.

H

M u l t i p l e Onslaughts

against A c q u i s i t i o n of Nutrients

We have d e s c r i b e d an approach t o h o s t p l a n t r e s i s t a n c e t h a t i n v o l v e s t h e use o f p l a n t o x i d a t i v e enzymes t o i r r e v o c a b l y d e p r i v e the i n s e c t o f n u t r i e n t s . We have emphasized t h a t t h e c h e m i c a l r e a c t i o n s c a t a l y z e d by POD and PPO have t h e p o t e n t i a l t o d e s t r o y a v a r i e t y o f e s s e n t i a l o r l i m i t i n g amino a c i d s (Table X ) . I n p a r t i c u l a r , these r e a c t i o n s a r e adept a t d e s t r o y i n g l y s i n e and cysteine. Integral lysine i s necessary f o r proper enzymatic h y d r o l y s i s o f p r o t e i n . C y s t e i n e and m e t h i o n i n e , amongst o t h e r u s e s , a r e r e q u i r e d t o s y n t h e s i z e t r y p s i n . The a c t i o n o f PPO and POD i n c o n j u n c t i o n w i t h P i ' s a r e p r o p o s e d t o p l a c e a s e v e r e s t r a i n on t h e i n s e c t f o r h i g h s u l p h u r amino a c i d i n t a k e . T h i s s t r a i n may be f u r t h e r e x a c e r b a t e d by t h e complementary a c t i o n o f quinones


187

188


d e p l e t i n g a v a i l a b l e glutathione v i a formation o f conjugates. Furthermore, s i m u l t a n e o u s a c t i o n o f AOX may l i m i t t h e q u a n t i t y o f e s s e n t i a l a s c o r b i c a c i d and p l a c e a f u r t h e r s t r a i n on c h e m i c a l and enzymatic r e d u c i n g power. These o x i d a t i v e c o n d i t i o n s a l s o have t h e p o t e n t i a l t o d e s t r o y e s s e n t i a l n u t r i e n t s such as t o c o p h e r o l (151) and t h i a m i n e (160).

T a b l e X.

Some N u t r i e n t s D e s t r o y e d o r Rendered L e s s A v a i l a b l e by P l a n t Chemical o r Enzymatic I n t e r a c t i o n s


Agent Ascorbic a c i d oxidase Lipoxygenase

Peroxidase (lysine,cysteine, histidine, tryptophan),

P h e n y l a l a n i n e ammonia l y a s e Polyphenol oxidase cysteine

Nutrient ascorbic acid l i n o l e n i c and l i n o l e i c a c i d s , β-carotene amino a c i d s ( l y s i n e , cysteine, histidine) protein methionine, tyrosine, above f r e e amino acids, ascorbic acid, thiamine phenylalanine protein (lysine, methionine,

histidine,

Proteinase i n h i b i t o r s utilization

t y r o s i n e ) , above f r e e amino a c i d s , a s c o r b i c a c i d , thiamine d i g e s t i o n and of p r o t e i n ( s u l p h u r amino a c i d s )

Tomatine

T y r o s i n e ammonia l y a s e

cholesterol, sitosterol and r e l a t e d phytosterols tyrosine

LOX destroys linoleic and l i n o l e n i c acids v i a their o x i d a t i o n t o l i p i d h y d r o p e r o x i d e s . These l i p i d hydroperoxides s u b s e q u e n t l y form h y d r o p e r o x i d e s , h y d r o p e r o x i d e free radicals, epoxides and malondialdehyde which can impair the n u t r i t i v e q u a l i t y o f p r o t e i n v i a mechanisms s i m i l a r t o those mediated by POD and PPO. These u n s a t u r a t e d f a t t y a c i d s a r e e s s e n t i a l f o r normal l a r v a l growth and m a t u r a t i o n . We have p r e s e n t e d e v i d e n c e (124) t h a t p h e n y l a l a n i n e and t y r o s i n e ammonia l y a s e s , two enzymes i n d u c e d d u r i n g wounding, have the p o t e n t i a l t o l i m i t t h e i n s e c t s ' i n t a k e o f f r e e p h e n y l a l a n i n e



12.

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and t y r o s i n e because t h e y are c o n v e r t e d t o n u t r i t i o n a l l y i n e r t cinnamic a c i d d e r i v a t i v e s . I n s e c t s a l s o r e q u i r e an exogenous s o u r c e o f p h y t o s t e r o l s ( 2 7 ) . The g l y c o a l k a l o i d tomatine i s an e f f e c t i v e p r e c i p i t a t o r o f c e r t a i n p h y t o s t e r o l s such as s i t o s t e r o l and c h o l e s t e r o l , and as such may p r o v i d e a means o f r e d u c i n g s t e r o l i n t a k e f o r n o c t u i d l a r v a e (97). The f e a s i b i l i t y o f u s i n g t h e s e a n t i n u t r i t i v e p l a n t systems as m u l t i p l e - f a c t o r / m u l t i p l e - m e c h a n i s m resistance against noctuid l a r v a e remains t o be determined. I t i s p o s s i b l e t h a t such a m u l t i p l e o n s l a u g h t a g a i n s t n u t r i e n t a c q u i s i t i o n i s redundant. I n o t h e r words, perhaps m e r e l y the use o f PPO and c h l o r o g e n i c a c i d i s s u f f i c i e n t . I t a l s o remains t o be d e t e r m i n e d whether t h i s p r o p o s e d multiple-factor/multiple-mechanism of resistance renders the i n s e c t s ' d e t o x i c a t i v e systems more s u s c e p t i b l e t o traditional c o n t r o l t a c t i c s , and whether the e v o l u t i o n o f r e s i s t a n c e t o such multiple antinutritive factors i s more difficult than to insecticides. Advantages o f the Use

o f Enzymatic Defenses

Our e v i d e n c e s u p p o r t s the c o n t e n t i o n t h a t p l a n t o x i d a t i v e enzymes can be used as c o n s t i t u t i v e and/or i n d u c i b l e a n t i n u t r i t i v e bases o f r e s i s t a n c e a g a i n s t i n s e c t s . T h i s r e s i s t a n c e i s b a s e d on the irreversible chemical degradation of multiple essential or l i m i t i n g n u t r i e n t s , w h i c h may be more d i f f i c u l t f o r the i n s e c t species to evolve biochemical r e s i s t a n c e against than against c l a s s i c a l "toxins". Other advantages a l s o a c c r u e from t h e i r use. Because t h e y are enzymes, o n l y c a t a l y t i c amounts are r e q u i r e d t o d r i v e the reactions, provided substrates are not limiting. I f one is c o n c e r n e d about the c o s t o f defense r e n d e r i n g the p l a n t l e s s agronomically efficient (15), when employing a battery of secondary gene p r o d u c t s as the bases o f resistance (e.g., t o m a t i n e , p h e n o l i c s , and 2 - t r i d e c a n o n e ) , perhaps the u t i l i z a t i o n o f PPO and POD i n c o n j u n c t i o n w i t h p h e n o l i c s i s more e f f i c i e n t . The s y n t h e s i s o f c a t a l y t i c amounts o f enzyme s h o u l d p l a c e l e s s m e t a b o l i c d r a i n on the p l a n t t h a n s y n t h e s i z i n g one o r s e v e r a l secondary p r o d u c t s t h a t u s u a l l y r e q u i r e l e v e l s o f 0.1% and above t o be a c t i v e . I n terms o f b r e e d i n g programs, i t s h o u l d be e a s i e r to manipulate the expression of primary gene p r o d u c t s through c l a s s i c a l (e.g., i n t r o d u c i n g e x o t i c genes from r e l a t e d s p e c i e s ) o r modern biotechnological procedures (e.g., amplifying gene e x p r e s s i o n ) t h a n t o m a n i p u l a t e the e x p r e s s i o n o f secondary gene products. C o n s i d e r i n g the i n c r e a s i n g l y s e v e r e c o n s t r a i n t s upon r e g i s t e r i n g g e n e t i c a l l y m o d i f i e d organisms f o r commercial use, i t might be e a s i e r t o r e g i s t e r p l a n t s t h a t c o n t a i n o n l y c a t a l y t i c q u a n t i t i e s o f enzymes, d e r i v e d from r e l a t e d s p e c i e s , t h a n t o r e g i s t e r p l a n t s t h a t must e x p r e s s h i g h l e v e l s o f t r a n s g e n i c gene p r o d u c t s ( e . g . , BT t o x i n , l e c t i n s , and P i ' s ) . Other advantages b e a r r e p e a t i n g . These enzymes have been i m p l i c a t e d i n r e s i s t a n c e t o pathogens, and hence, t h e i r d i r e c t e d utilization against insects may complement resistance to pathogens. Three enzymes (PPO, POD, and LOX) have b r o a d pH



190


p r o f i l e s which permit t h e i r operation i n the a c i d i c c o n d i t i o n s o f i m m e d i a t e l y c r u s h e d f o l i a g e (pH - 5.5) and i n t h e b a s i c c o n d i t i o n s o f t h e i n s e c t ' s g u t (pH 8.5). Furthermore, PPO and POD a r e a l m o s t completely r e s i s t a n t t o d i g e s t i o n by t r y p t i c and chymotryptic enzymes and thus remain a c t i v e i n t h e i n s e c t ' s g u t d u r i n g d i g e s t i o n o f food. PPO i s a c t u a l l y a c t i v a t e d by t h e g u t p r o t e a s e s . These p l a n t enzymes a r e i n d u c i b l e by v a r i o u s k i n d s o f f e e d i n g damage, w h i c h s h o u l d e x a c e r b a t e t h e i r e f f e c t s . And, f i n a l l y , t h e phenology o f t h e tomato, l i k e most p l a n t s (151,161-164), f a v o r s the a c t i o n o f t h e s e enzymes. As tomato p l a n t s age t h e y become more o x i d a t i v e by h a v i n g l e v e l s o f PPO, POD, and LOX i n c r e a s e , w h i l e l e v e l s o f p l a n t n i t r o g e n and c a t a l a s e f a l l (79; u n p u b l . d a t a ) . Even i n t h e green f r u i t s t a g e , tomato p l a n t s a r e o x i d a t i v e . I t may be p o s s i b l e t o a c c e n t u a t e t h e o x i d a t i v e s t a t e o f t h e p l a n t t h r o u g h o u t i t s l i f e t o f a c i l i t a t e r e s i s t a n c e . However, t h i s e f f o r t might be a t odds w i t h o t h e r s ' attempts t o b r e e d l e s s " o x i d a t i v e " p l a n t s i n o r d e r t o decrease s u s c e p t i b i l i t y t o h e r b i c i d e s (165). T h i s form o f r e s i s t a n c e i s t a r g e t e d a g a i n s t i n s e c t s w i t h b a s i c g u t s ( i . e . , l e p i d o p t e r a n l a r v a e ) . The b a s i c g u t environment f a v o u r s o x i d a t i v e c o n d i t i o n s and t h e t y p e s o f r e a c t i o n s p r o p o s e d (e.g., S c h i f f base formation, alkylation, co-oxidation, and a u t o o x i d a t i o n ) . However, w i t h i n s e c t s (e.g., t h e C o l o r a d o P o t a t o b e e t l e L e p t i n o t a r s a d e c e m l i n e a t a ) h a v i n g a c i d i c g u t f l u i d (pH 6.0 - 6.5), t h e p r o p o s e d mechanisms may be o f l i t t l e v a l u e . I n a c i d i c c o n d i t i o n s , S c h i f f base f o r m a t i o n and a l k y l a t i o n o f n u c l e o p h i l i e s are n o t f a v o r e d because t h e n u c l e o p h i l i c groups a r e p r o t o n a t e d . We have shown i n l a r v a l L. d e c e m l i n e a t a t h a t p l a n t p r o t e i n i s n o t s i g n i f i c a n t l y a l k y l a t e d by PPO and c h l o r o g e n i c acid (unpubl. d a t a ) . A l t e r n a t e t a c t i c s might be n e c e s s a r y f o r s i m u l t a n e o u s c o n t r o l o f l a r v a l b e e t l e s and n o c t u i d s . Conclusion We have p r o p o s e d t h e use o f s e v e r a l p l a n t enzymes as a p o l y g e n i c b a s i s o f r e s i s t a n c e against n o c t u i d l a r v a e through a c t i v a t i o n o f b o t h " t o x i n s " and " n u t r i e n t s " t o forms t h a t c h e m i c a l l y reduce t h e n u t r i t i o n a l v a l u e o f t h e tomato p l a n t . A l t h o u g h t h i s approach may be u s e f u l i n d e v e l o p i n g r e s i s t a n c e t h a t i s d u r a b l e , t h e use o f such enymes i s c o m p l i c a t e d by t h e i r mutual i n t e r a c t i o n s and t h e c h e m i c a l c o n t e x t o f t h e p l a n t , by t h e d e t o x i c a t i v e a b i l i t i e s o f the i n s e c t , and by t h e i r u n p r e d i c t a b l e e f f e c t s upon b i o l o g i c a l c o n t r o l a g e n t s . Such an approach may be w a r r a n t e d i n v i e w o f p u b l i c d i s d a i n f o r p e s t i c i d e s ; such r e s i s t a n c e may o f f e r n o t o n l y s i m u l t a n e o u s r e s i s t a n c e a g a i n s t pathogens and i n s e c t s , b u t a l s o o f f e r resistance that i s environmentally safe, thus, lessening r e l i a n c e on c o n v e n t i o n a l c o n t r o l t a c t i c s . On a l e s s o p t i m i s t i c n o t e , t h e f o r t h r i g h t u t i l i z a t i o n o f t h e above a n t i n u t r i t i v e defenses may be p r a g m a t i c a l l y d i f f i c u l t from the s t a n d p o i n t o f breeding. The e x p r e s s i o n o f p h e n o l i c s , and l i k e l y many o f t h e o t h e r characters, a r e under q u a n t i t a t i v e genetic c o n t r o l . Hence, d e r i v i n g p r e d i c t a b l e r e s i s t a n c e , as prescribed above, w i t h o u t the h i g h l y modulating e f f e c t s o f environment and p o t e n t i a l gene i n t e r a c t i o n s may p r e s e n t i t s own s e t o f problems. Furthermore, many o f t h e c a n d i d a t e enzymes a r e m u t u a l l y and i n t i m a t e l y i n v o l v e d i n t h e p l a n t ' s defense a g a i n s t


12.

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m i c r o b e s , i n d e t o x i c a t i o n and g e n e r a l m e t a b o l i s m , and i n p r o c e s s e s o f m a t u r a t i o n and senescence. The e f f e c t s o f m a n i p u l a t i n g the e x p r e s s i o n o f s u c h enzymes on the g e n e r a l agronomic v a l u e o f the p l a n t i s unknown. Acknowledgments T h i s work was s u p p o r t e d by the USDA C o m p e t i t i v e G r a n t s Program t h r o u g h g r a n t s USDA 89-37250-4639 t o S.S.D and G W.F., and USDA 87-CRCR-1-2371 t o S.S.D. Literature Cited


1.

2. 3. 4. 5.

6.

7. 8. 9. 10.

11.

12.

13.

14. 15. 16.

17. 18.

Hare, J . D. In Variable Plants and Herbivores i n Natural and Managed Systems; Denno, R. F.; McClure, M. S., Eds; Academic Press: New York, 1983; Chapter 18. Mattson, W. J . Ann. Rev. Ecol. Syst. 1980, 11, 119-61. Mattson, W. J . ; Haack, R. A. BioScience 1987, 37, 110-18. Price, P. W. Insect Ecology; John Wiley & Sons: New York, 1984; p 606. Scriber, J . M. In Chemical Ecology of Insects; B e l l , W. J . ; Carde, R. T., Eds.; Sinauer Associates Inc.: Sunderland, Massachusetts, 1984b; pp 159-202. Strong, D. R.; Lawton, J . H.; Southwood, S i r R. Insects On Plants. Community Patterns and Mechanisms; Harvard University Press: Cambridge, Massachusetts; 1984. White, T. C. R. Oecologia 1984, 63, 90-105. Barbosa, P.; Schultz, J . C., Eds. Insect Outbreaks; Academic Press: New York, 1987; p 578. Coley, P. D.; Bryant, J . P.; Chapin, F. S. Science 1985, 230, 895-99. Denno, R. F.; McClure, M. S., Eds. Variable Plants and Herbivores i n Natural and Managed Systems; Academic Press: New York; 1983, p 717. Mattson, W. J . ; Levieux, J . ; Bernard-Dagan, C. Eds. Mechanisms of Woody Plant Defenses Against Insects. Search for Pattern; Springer-Verlag: B e r l i n , 1988; p 416. McClure, M. S. In Variable Plants and Herbivores i n Natural and Managed Systems: Denno, R.F.; McClure, M. S., Eds.; Acadmeic Press: New York, 1983, pp 135-54. Rhoades, D. F. In Variable Plants and Herbivores i n Natural and Managed Systems; Denno, R.F.; McClure, M. S., Eds.; Acadmeic Press: New York, 1983, pp 155-220. Rhoades, D. Amer. Nat. 1985, 125, 205-38. Kogan, M. In IPM and Ecological Practise; Kogan, M., Ed.; John Wiley and Sons: New York, 1986; pp 83-134. Maxwell, F. G.; Jennings, P. R., Eds. Breeding Plants Resistant to Insects; Wiley Interscience: New York, 1980; p 683. Panda, N. Principles of Host-Plant Resistance to Insect Pests; Allanheld/Universe: New York, 1979; p 386. Smith, C. M. Plant Resistance to Insects. A Fundamental Approach; John Wiley and Sons: New York, 1989; p 286.


191

192

NATURALLY OCCURRING PEST BIOREGULATORS 19.

20. 21.

22. 23. 24.


25. 26. 27. 28.

29. 30. 31.

32. 33. 34. 35. 36. 37.

38.

39.

40.

41.

42.

Feeny, P. P. Coevolution of Animals and Plants; G i l b e r t , L. E.; Raven, P. Η., Eds.; University of Texas Press: Austin, 1975, pp 1-19. Moore, R. F. J . Econ. Entomol. 1983, 76, 697-99. Rhoades, D. F. In Herbivores: Their Interaction with Secondary Plant Metabolites; Rosenthal, G. Α.; Janzen, D. Η., Eds.; Academic Press: New York, 1979; pp 1-54. Bernays, E. A. Ecol. Entomol. 1981, 6, 353-60. Martin, J . S.; Martin, M. M. Oecologia 1982, 54, 205-311. Martin, J . S.; Martin, M. M.; Bernays, E. A. J . Chem. Ecol. 1987, 13, 605-21. Reese, J . C.; Chan, B. G.; Waiss, A. C., J r . J . Chem. Ecol. 1982, 8, 1429-36. Zucker, W. V. Amer. Natur. 1983, 121, 335-65. Dadd, R. H. Ann. Rev. Entomol. 1973, 18, 381-419. Brodbeck, B.; Strong, D. In Insect Outbreaks; Barbosa, P.; Schultz, J . C., Eds.; Academic Press: New York, 1987; pp 347-64. van Emden, H. F. In Phytochemical Ecology; Harborne, J.,Ed.; Academic Press: London, 1972; pp 25-43. Penny, L. H.; Scott, G. E.; Guthrie, W. D. Crop S c i . 1967, 7, 407-9. Birk, Y.; Peri, I. In Toxic Constituents of Plant Foodstuffs; Liener, I. Ε., Ed.; Academic Press: New York, 1980; pp 161-82. Bloem, Κ. Α.; Kelley, K. C.; Duffey, S. S. J . Chem. Ecol. 1989, 15, 387-98. Silano, V. Cereal Chem. 1978, 55, 722-31. Silano, V.; Zahnley, J . C. Biochim. Biophys. Acta. 1978, 533, 181-5. Shukle, R. H.; Murdock, L. L. Environ. Entomol. 1983, 12, 787-91. Apostol, I.; Heinstein, P. F.; Low, P. S. Plant Physiol. 1989, 90, 109-16. Boiler, T. In C e l l u l a r and Molecular Biology of Plant Stress; Key, L.; Kosuge,T., Eds; Alan R. L i s s , Inc.: New York, 1985; pp 247-62. Boller, T. In Plant-Microbe Interactions. Molecular and Genetic Perspective; Kosuge, T.; Nester, E. W., Eds.; MacMillan Publ. Company: New York, 1987; pp 385-413. Davies, E. The Biochemistry of Plants. A Comprehensive Treatise. Physiology of Metabolism; Davies, Ε., Ed.; Academic Press: New York, 1987; Vol. 12, pp 243-64. Esquerre-Tuagaye, M. T.; Mazau, D.; P e l i s s i e r , B.; Roby, D.; Runeau, D.; Toppan, A. In C e l l u l a r and Molecular Biology of Plant Stress; Key, J . L.; Kosuge, T., Eds.; Alan R. L i s s Inc.: New York, 1985; pp 459-73. Gianinazzi, S. Plant-Microbe Interactions. Molecular and Genetic Perspective; Kosuge, T.; Nester, E. W., Eds.; MacMillan Publ. Company: New York, 1984; pp 321-42. Hahlbrock, K.; Scheel, D. In Innovative Approaches to Plant Disease Control; Chet, I.,Ed; Wiley and Sons: New York, 1987; pp 228-54.


DUFFEY AND FELTON 43.

44.

45.

46.


47.

48. 49. 50. 51. 52.

53. 54. 55. 56. 57.

58. 59. 60.

61. 62. 63. 64. 65.

66.


Kahl, G. In The New Frontiers i n Plant Biochemistry; Akazawa, T.; Asahia, T; Imaseki, Η., Eds; Martinus Nijhoff/Dr. W. Junk Publishers: The Hague, 1983; pp 193-216. Kuc, J.; Lisker, Ν. In Biochemistry of Wounded Plant Tissues. Kahl, G., Ed.; Walter de Gruyter: B e r l i n , 1987; pp 203-42. Rhodes, J . M.; Wooltorton, L. S. C. In Biochemistry of Wounded Plant Tissues; Kahl, G., Ed.; Walter de Gruyter: B e r l i n , 1978; pp 243-86. Ryan, C. Α.; Bishop, P. D.; Graham, J . S.; Meyer-Broadway R.; Duffey, S. S. J . Chem. Ecol. 1985, 12, 1025-36. Butt, V. S. In The Biochemistry of Plants. A Comprehensive Treatise. Metabolism and Respiration; Stumpf, P. K.; Conn,.E. Ε., Eds; Academic Press: New York, 1981; V o l . 2, pp 81-123. Fry, S. C. Ann. Rev. Plant. Physiol 1986, 37, 165-86. G a l l i a r d , T. In Biochemistry of Wounded Plant Tissues; Kahl, G., Ed.; Walter de Gruyter: B e r l i n , 1978; pp 155-201. Gardner, H. W. J . Agric. Food Chem. 1979, 27, 220-29. Ampomah, Υ. Α.; Friend, J . Phytochemistrv 1988, 27, 253341. Elstner, E. F. In The Biochemstrv of Plants. A Comprehensive Treatise. Biochemistry and Metabolism; Davies, D. D., Ed.; Academic Press: New York, 1980; V o l . 11, pp 253-315. Mayer, A. M. Phytochemistrv 1987, 26, 11-20. Mayer, A. M.; Harel, E. Phytochemistry 1979, 18, 193-215. Mohan, R.; Kolattukudy, P. Plant Physiol. 1990, 921, 27680. Pierpoint, W. S.; Ireland, R. J . ; Carpenter, J . M. Phytochemistry 1977, 16, 29-34. Stahmann, M. A. In The New Frontiers i n Plant Biochemistry; Akazawa, T.; Asahia, T.; Imaseki, Η., Eds; Martinus Nijhoff/Dr. W. Junk Publishers: The Hague, 1983; pp 237-50. G a l l i a r d , T.; Matthew, J . A. Phytochemistrv 1977, 16, 33943. Gentile, I. Α.; F e r r a r i s , L.; Matta, A. J . Phytopathol. 1988, 122, 45-53. Hobson, G. E.; Davies, J . N. In The Biochemistry of F r u i t s and Their Products.; Hulme, A. C., Ed.; Academic Press: New York, 1971; V o l . 2, pp 437-82. Raman. K.; Sanjayan, K. P. Proc. Indian Acad. S c i . (Animal Sci.), 1984, 93(6), 543-7. Reuveni, R.; Ferreira, J . F. Phytopath. Z. 1985, 112, 1937. H u r r e l l , R. F.; Finot, P. Α.; Cuq, J . L. J . N u t r i t i o n 1982, 42, 191-211. Vaughn, K. C.; Duke, S. O. Physiol. Plant 1984, 60, 106-12. H u r r e l l , R. F.; Finot, P. A. In D i g e s t i b i l i t y and Amino Acid A v a i l a b i l i t y i n Cereals and Oilseeds; Finley, J . W.; Hopkins, D. T., Eds.; American Association of Cereal Chemists, Inc.: St. Paul, 1982; pp 233-46. Davies, A. M. C.; Newby, V. K.; Synge, R. L. M. J. Sci. Food Agric. 1978, 29, 33-41.


193

194 67. 68. 69.

70. 71.


72. 73.

74.

75.

76. 77.

78.

79. 80. 81. 82. 83. 84.

85. 86. 87. 88. 89. 90. 91.

NATURALLY OCCURRING PEST BIOREGULATORS Leatham, G. F.; King, V.; Stahmann, M. A. Phytopathology 1980, 70, 1134-40. Matheis, G.; Whitaker, J . R. J . Food Biochem. 1987, 11, 309-27. Pierpoint, W. S. In Leaf Protein Concentrates; Telek, L.; Graham, H. D., Eds.; A v i Publ. Comp., Inc.: Wesport, Connecticut, 1983; pp 235-67. Motoda, S. J . Ferment. Technol. 1979, 57, 395-9. Stahmann, Μ. Α.; Spencer, A. K.; Honold, G. R. Biopolymers 1977, 16, 1307-18. Whitmore, F. W. Plant S c i . Letters 1978, 13, 241-5. Kanner, J . ; German, J . B.; K i n s e l l a , J . E. In C r i t i c a l Reviews i n Food Science and N u t r i t i o n ; Furia, T. Ε., Ed.; CRC Press: Boca Raton, 1987; pp 317-65. Vick, Β. Α.; Zimmerman, D. C. In The Biochemistry of Plants. A Comprehensive Treatise. L i p i d s : Structure and Function; Stumpf, P. Κ., Ed.; Academic Press: New York, 1987; V o l . 9, pp 53-90. B e l i t z , H.-D.; Grosch, W., Eds. Food Chemistry. (translated from German by D. Hadziyev); Springer Verlag: B e r l i n , 1987; p 774. Matsushita, S. J . Agric. Food Chem. 1975, 23, 150-5. Ory, R. L.; St. Angelo, A. J . In Food Protein Deterioration. Mechanisms and Functionality: Cherry, J . P., Ed.; American Chemical Society: Washington, DC, 1982; pp 5566. W i l l s , E. D. In Biochemical Toxicology, A P r a c t i c a l Approach; Snell, K.; Mullock, Β., Eds.; IRL Press: Washington, DC, 1985; pp 127-52. Felton, G. W.; Donato, K.; Del Vecchio, R. J . ; Duffey, S. S. J. Chem. Ecol. 1989, 15, 2667-94. Dryden, M. J . ; Saterlee, L. D. J . Food Science 1978, 43, 650-1. Eklund, A. Nutr. Metab. 1975, 18, 258-264. Friedman, M. Protein N u t r i t i o n a l Quality of Foods and Feeds; Marcel Dekker, Inc.: New York, 1975. Horigome, T.; Kandatsu, T. Agric. B i o l . Chem. 1968, 32, 1093-1102. H u r r e l l , R. F.; Finot, P. In N u t r i t i o n a l and Toxicological Aspects of Food Safety: Friedman, M., Ed.; Plenum Press: New York, 1984; pp 423-36. Jung, H.-J. G.; Fahey, G. C., J r . J . Agric. Food Chem. 1981, 29, 817-20. Lahiry, N. L.; Satterlee, H. W.; Wallace, G. W. J . Food Science 1977, 42, 83-85. Lee, H. S.; Louriminia, S. S.; C l i f f o r d , A. J . ; Whitaker, J . R.; Feeny, R. A. J . N u t r i t i o n 1978, 108, 687-97. Barbeau, W. E.; K i n s e l l a , J . E. J . Agric. Food. Chem. 1983, 31, 993-98. Barbeau, W. E. ; K i n s e l l a , J . E. J . Food S c i . 1985, 50, 1083-1100. Finot, P. A. Qual. Plant Foods Hum. Nutr. 1983, 32, 439-53. Anderson, P. A. In D i g e s t i b i l i t y and Amino Acid Availability i n Cereals and Oilseeds: Finley, J . W.;


12.

DUFFEY AND FELTON

92. 93. 94. 95. 96.


97.

98. 99.

100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117.

118. 119.


Hopkins, D. T., Eds.; Amer. Assoc. Cereal Chemists, Inc.: St. Paul, 1985; pp 31-44. Igarashi, K.; Tsunekuni, T.; Yasui, T. J. Nutrition Sci. Vitaminol. 1983, 29, 227-32. Rock, G. C.; Hogdson, E. J . Insect Physiol. 1971, 17, 108797. Broadway, R. M.; Duffey, S. S. J . Insect Physiol. 1986, 32, 673-80. Broadway, R. M.; Duffey, S. S. J . Insect Physiol. 1986, 32, 827-33. Broadway, R. M.; Duffey, S. S. J . Insect Physiol. 1988, 34, 1111-17. Duffey, S. S.; Bloem, K. A. In Ecological Theory and IPM Practice; Kogan, M., Ed.; John Wiley & Sons: London, 1986; pp 135-83. Kauffman, W. C.; Kennedy, G. G. J . Chem. Ecol. 1989, 15, 2051-60. Duffey, S. S. In Insects and Plant Surfaces; Southwood, S i r R.; Juniper, Β., Eds.; Edward Arnold: London, 1986; pp 15172. H a l l , C. B.; Knapp, F. W.; S t a l l , R. E. Phytopathology 1969, 59, 267-8. Rick, C. M.; Fobes, J . F. Proc. Nat. Acad. S c i . 1976, 73, 900-4. Duffey, S. S.; Isman, M. B. Experientia 1981, 37, 574-6. E l l i g e r , C. Α.; Wong, Y.; Chan, B. G.; Waiss, A. C., J r . J. Chem. Ecol. 1981, 7, 753-8. Strack, D.; Gross, W. Plant Physiol. 1990, 92, 41-7. Ryan, J . D.; Gregory, P.; Tingey, W. M. Phytochem. 1982, 8, 1185-7. Carrasco, Α.; Boudet, A. M.; Marigo, S. Physiol. Plant Pathol. 1978, 12, 225-32. Chadha, K. C.; Brown, S. A. Can. J . Bot. 1974, 52, 2041-7. Matta, Α.; Gentile, I.; G i a i , I. Phytopathol. 1969, 59, 512-13. Mendez, J . ; Brown, S. A. Can. J . Bot. 1971b, 49, 2101-05. Pollock, C. J . ; Drysdale, R. B. Phytopath. Z. 1976, 86, 5666. Buttery, R. G.; Teranishi, R. ; Ling, L. C. J . Agric. Food Chem. 1987, 35,540-546. Buttery, R. G.; Ling, L. C.; Light, D. M. J . Agric. Food Chem. 1987, 35, 1039-42. Zamora, R.; Olias, J . M.; Mesias, J . L. Phytochemistry 1987, 26, 345-7. Hildebrand, D. F. Physiol. Plant. 1989, 76, 249-53. Hildebrand, D. F.; Rodriquez, J . G.; Brown, G. C.; Luu, K. T.; Volden, C. S. J . Econ. Entomol. 1986, 79, 1459-65. Neese, P. A. Poster STD0017; Entomol. Soc. Amer. Natl. Conf. Exh., Dec., 1988, L o u i s v i l l e , Kentucky. Ryan, C. A. In Advances i n Plant Gene Research: Verma, O. S. P.; Hohns, T., Eds.; Springer-Verlag: B e r l i n , 1984; pp 321-32. Weiel, J . ; Hapner, K. D. Phytochemistry 1976, 15, 1885-7. Thornburg, R. W.; Kernan, Α.; Molin, L. Plant Physiol. 1990, 92, 500-5.


195

196 120.

121. 122. 123. 124.

125. Downloaded by CORNELL UNIV on August 2, 2012 | http://pubs.acs.org Publication Date: January 9, 1991 | doi: 10.1021/bk-1991-0449.ch012

126. 127. 128. 129.

130. 131. 132. 133. 134. 135. 136.

137. 138. 139. 140. 141. 142. 143. 144. 145. 146.

NATURALLY OCCURRING PEST BIOREGULATORS Foard, D. E.; Murdock, L. L.; Dunn, P. E. In Plant Molecular Biology; Alan R. L i s s , Inc.: New York, 1983; pp 223-33. Hilder, V. Α.; Angharad, A. M. R.; Gatehouse, Sheerman S. E.; Barker, R. E.; Boulter, D. Nature 1987, 300, 160-3. Thornburg, R. W.; Cleveland, A. G.; Johnson, R.; Ryan, C. A. Proc. Natl. Acad. S c i . 1987, 84, 744-8. Broadway, R.; Duffey, S. S.; Pearce, G.; Ryan, C. A. Entomol. Exp. Appl. 1986, 41, 33-8. Duffey, S. S.; Felton, G. W. In Biocatalysis i n A g r i c u l t u r a l Biotechnology; Amer Chem. Soc. Symp. Ser. 389, 1989; pp 289-313. Felton, G. W.; Broadway, R. M.; Duffey, S. S. J . Insect Physiol. 1989, 35, 981-90. Lange, W. H.; Bronson, L. Ann. Rev. Entomol. 1981, 26, 34571. Kennedy, G. G. Entomol. Soc. Amer. B u l l . 1978, 24, 375-84. Dimock, Μ .Α.; Kennedy, G. G. Ent. Exp. Appl. 1983, 33, 263-8. Lee, J . S.; Brown, W. E.; Graham, J . S.; Pearce, G.; Fox, E. Α.; Dreher, T. W.; Ahren, K. G.; Pearson, G. D.; Ryan, C. A. Proc. Natl. Acad. S c i . 1986, 83, 7277-81. Liener, I. E. Ed. Toxic Constituents of Plant Foodstuffs; Academic Press: New York, 1980; p 500. Plunkett, G.; Senear, D. F.; Zuroske, G.; Ryan, C. A. Arch. Biohem. Biophys. 1982, 213, 463-72. Meeusen, R. L.; Warren, G. Ann. Rev. Entomol. 1989, 34, 373-81. Felton, G. W.; Duffey, S. S.; V a i l , P. V.; Kaya, Η. K.; Manning, J . J . Chem. Ecol. 1987, 13, 947-57. Felton, G. W.; Duffey, S. S. J . Chem. Ecol. 1989, 36. Barton, Κ. Α.; Whiteley, H. R.; Yang, N.-S. Plant Physiol. 1987, 85, 1103-09. Hammock, B. D.; Harshman, L. G.; Philpott, M. L.; Szekacs, Α.; Ottea, J . Α.; Newitt, R. Α.; Wroblewski, V. J . ; Halarnakar, P. P.; Hanzlik, T. N. In Biomechanisms Regulating Growth and Development; Steffens, G. L.; Rumsey, T. S., Eds; Kluwer Academic Publishers: The Netherlands, 1988; pp 137-73. Maeda, S. Ann. Rev. Entomol. 1989, 34, 351-72. Cadenas, Ε. Ann. Rev. Biochem. 1989, 58, 79-110. Fridovich, I. Science 1978, 201, 875-80. Cheynier, V. F.; Van Hulst, M. W. J . J . Agric. Food Chem. 1988, 36, 10-14. Cheynier, V.; Osse, C.; Rigaud, J . J . Agric. Food Science 1988, 53, 1729-33. Cohen, G.; Heikkila, R. E. J . B i o l . Chem. 1974, 249, 244752. Hanham, A. F.; Dunn, B. P.; Stich, H. F. Mutation Research 1983, 116, 333-9. Dalton, D. Α.; Russell, S. Α.; Hanus, F. J . ; Pascoe, G. Α.; Evans, H. J . Proc. Natl. Acda. S c i . 1986, 83, 3811-15. Dalton, D. Α.; Hanus, F. J . ; Russell, S. Α.; Evans, H. J . Plant Physiol. 1987, 83, 789-94. Rennenberg, H. Phytochemistry 1982, 21, 2771-81.


12.

DUFFEY AND FELTON

147.

148. 149. 150.


151. 152. 153. 154.

155.

156.

157. 158. 159. 160. 161. 162. 163. 164.

165.


Pritsos, C. Α.; Ahmad, S.; Bowen, S. M.; E l l i o t , A. J . ; Blomquist, G. J . ; Pardini, R. S. Arch. Insect Biochem. Physiol. 1988, 8, 101-12. Torel, J . ; C i l l a r d , J . ; C i l l a r d , P. Phytochemistry 1986, 25, 383-5. Kramer, K. J . ; Hendricks, L. H.; Liang, Y. T.; Seib, P. A. J. Agric. Food Chem. 1978, 26, 874-8. Barraccino, G.; Dipierro, S.; Arrigoni, O. Phytochemistry 1989, 28, 715-17. Kunert, K. J . ; Edcere, M. Physiol. Planta 1985, 65, 85-8. Larson, R. A. Phytochemistry 1988, 27, 969-78. Meister, A. Science 1982, 220, 472-8 Ahmad, S.; Pritsos, C. Α.; Bowen, S. M.; Kirkland, Κ. E.; Blomquist, G. J . ; Pardini, R. S. Arch. Insect Biochem. Physiol. 1987, 6, 85-96. Ahmad, S.; Pritsos, C. Α.; Bowen, S. M.; Heisler, C. R.; Blomquist, G. J . ; Pardini, R. S. Free Rad. Res. Comms. 1988, 4, 403-8. Ahmad, S.; Pritsos, C. Α.; Bowen, S. M.; Heisler, C. R.; Blomquist, G. J . ; Pardini, R. S. Arch. Insect Biochem. Physiol. 1988, 7, 173-86. Pritsos, C. Α.; Ahmad, S.; Bowen, S. M.; Blomquist, G. J . ; Pardini, R. S. Comp. Biochem. Physiol. 1988, 90C, 423-7. Fridovich, I. J . B i o l . Chem. 1989, 264, 7761-4. Khan, V. Phytochemistry 1983, 22, 2155-9. Panijpan, B.; Ratanaubolchai, K. Internatl. J . V i t . Nutr. Res. 1980, 50, 247-53. Choudhuri, M. A. Plant. Physiol. Biochem. 1988, 15, 18-29. Dhindsa, R. S.; Plumb-Dhindsa, P.; Thorpe, T. A. J . Exp. Botany 1981, 32, 93-101. Stewert, R. R. C.; Bewley, J . D. Plant Physiol. 1980, 65, 245-8. Thompson, J . E. In Senescence and Aging i n Plants;Nooden, L. D.; Leopold, A. C., Eds.; Academic Press: New York, 1988; pp 51-83. Schmidt, Α.; Kunert, K. J . Molecular Strategies f o r Crop Protection;rntzen, C. J . ; Ryan, C.; Eds.; Alan R. L i s s : New York, 1987; p 443.

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