C h a p t e r 12
Resistance of Cereal Crops to Aphids: Role of Allelochemicals Luis J. Corcuera, Victor H. Argandona, and Gustavo E. Zuniga
Downloaded via UNIV OF MINNESOTA on July 10, 2018 at 14:18:06 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
Aphids cause important economic losses in cereals. Thus, development of resistant varieties is desirable. This paper describes the possible role of various natural chemical compounds in the resistance of barley, wheat, triticale and maize to the aphidsSchizaphisgraminum, Rhopalosiphum padi andMetropolophiumdirhodum.Resistance of barley to aphids may be affected by the concentration of the alkaloid gramine. Conversely, increased susceptibility of barley seedlings grown under water stress is partially caused by accumulation of glycine-betaine in their leaves. Resistance of wheat, triticale and maize to these insects is mainly determined by the presence of hydroxamic acids. R e s i s t a n c e o f p l a n t s t o h e r b i v o r o u s animals i s determined in many c a s e s by t h e p r e s e n c e i n p l a n t t i s s u e s o f s e c o n d a r y m e t a b o l i t e s t h a t may cause f e e d i n g d e t e r r e n c e or t o x o c i t y t o t h e a n i m a l . I n s e c t s cause damage t o c e r e a l s , d e c r e a s i n g g r a i n p r o d u c t i o n . Development o f v a r i e t i e s r e s i s t a n t t o i n s e c t s i s then d e s i r a b l e f o r improving cereal productivity. R e s i s t a n c e o f b a r l e y t o a p h i d s has been r e p o r t e d t o be i n f l u e n c e d by t h e p r e s e n c e o f s e v e r a l p h e n o l i c and f l a v o n o i d compounds (V) . Gramine and r e l a t e d i n d o l e a l k a l o i d s cause t o x i c i t y in ruminants f e e d i n g on v a r i o u s Gramineae and Leguminosae ( 2 . 3 ) . These alkaloids have a l s o been r e p o r t e d t o c a u s e t o x i c i t y and f e e d i n g d e t e r r e n c e t o aphids ( 4 , 5 ) . S i n c e t h e s e compounds a l s o d e c r e a s e p a l a t a b i l i t y of f o d d e r p l a n t s , i t h a s been p r o p o s e d t o r e d u c e t h e a l k a l o i d c o n t e n t o f v a r i o u s Gramineae by p l a n t b r e e d i n g ( 6 ) . R e s i s t a n c e o f Sorghum t o t h e greenbug SchZzaphXb gHarrUnum a p p e a r s t o be a f f e c t e d by the degree o f m e t h y l a t i o n o f t h e i n t e r c e l l u l a r p e c t i n ( 2 ) . Sorghum ( £ ) , b a r l e y ( £ ) , and o t h e r c e r e a l s have c y a n o g e n i c g l u c o s i d e s t h a t may be i m p o r t a n t i n p l a n t p r o t e c t i o n . D h u r r i n was i d e n t i f i e d as a f e e d i n g d e t e r r e n t towards t h e greenbug (IQ) . D h u r r i n i s l o c a t e d e n t i r e l y i n e p i d e r m a l c e l l s o f Sorghum l e a v e s ( 1 1 ) . Hydroxamic a c i d s may be i m p o r t a n t i n d e t e r m i n i n g t h e r e s i s t a n c e o f maize t o t h e European corn b o r e r OAfrUyuA nubXZatu (12) and o f wheat and m a i z e t o a p h i d s ( l j 15). These compounds a r e found more c o n c e n t r a t e d i n t h e vascular t i s s u e s than i n o t h e r p a r t s o f t h e l e a f ( 1 6 ) .
0097-6156/87/0330-0129$06.00/0 © 1987 American Chemical Society
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
130
ALLELOCHEMICALS: ROLE IN AGRICULTURE AND
FORESTRY
In this paper we summarize our work on the r o l e of indole alkaloids and hydroxamic acids on the resistance of cereals to aphids. In addition, we describe the effects of water stress on suscept i b i l i t y of barley to aphids. Results S u s c e p t i b i l i t y to aphids and gramine and hydroxamic acid content. Seedlings of several species of cereals were infested with aphids.At this time, the content of gramine and hydroxamic acids in the leaves was measured. Six days l a t e r aphid population growth rate was measured. Gramine was found only in barley while hydroxamic acids were present in wheat, t r i t i c a l e , and maize (Table I ) . Correlations were observed between resistance of barley to aphids and gramine content. Correlation c o e f f i c i e n t s between gramine content and population growth rate of
RkopaloA^pkum
padi
and
\hdtopotophlum
duikodum
were
-0.99, and -0.96, and -0.99, respectively. R. padLC was more affected than S. Qhaminum and M. duikodum by the gramine content of leaves. S i m i l a r l y , hydroxamic acid content of leaves of wheat, t r i t i c a l e and maize correlated with resistance to S. g^arrUnum and M . dùihodum. D i s t r i b u t i o n of compounds i n barley and wheat tissues. Tissues of barley and wheat leaves were mechanically separated under the microscope. It was observed that i n barley gramine was more concentrated i n the epidermis than i n the entire l e a f (Table I I ) . Hydroxamic acids i n wheat were absent in epidermic tissues and were more concentrated in the vascular tissues than in the entire l e a f . Neither compound was detected in xylem exudates nor in guttation drops. B i o l o g i c a l a c t i v i t y of gramine and hydroxamic acids. Gramine decreased s u r v i v a l , feeding, and reproduction of aphids in a r t i f i c i a l diets (Table III) at a concentration s i m i l a r to those found i n leaves of several barley c u l t i v a r s . DIMBOA, 2,4-Dihydroxy-7-methoxy-l,4benzoxazin-3-one (the main hydroxamic acid from wheat and maize),and i t s glucoside also showed deleterious effects on the aphids at concentration l e v e l s found in leaves of wheat and maize. E f f e c t of water stress on s u s c e p t i b i l i t y of barley to aphids. Barley seedlings were subjected to water stress. These plants accumulated among other compounds proline and glycine-betaine (Table IV). Also, the more stressed plants were the most susceptible to aphids. The c u l t i v a r used in this experiment lacked gramine. However, when a gramine-containing c u l t i v a r was used gramine concentration was not affected by water s t r e s s . To test i f some stress compounds had b e n e f i c i a l e f f e c t s on aphids proline, choline and glycine-betaine were incorporated into a r t i f i c i a l d i e t s . Proline and choline appeared to decrease s u r v i v a l of aphids, while glycine-betaine did not (Table V). Moreover, glycinebetaine caused a d r a s t i c increase in aphid reproduction. Thus, the increased s u s c e p t i b i l i t y to aphids of water stressed plants may be p a r t i a l l y due to the higher content of glycine-betaine.
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
12.
Resistance of Cereal Crops to
CORCUERA ET AL.
Table I.
131
Aphids
Gramine and Hydroxamic A c i d Content and S u s c e p t i b i l i t y of V a r i o u s C e r e a l s to A p h i d s Compounds (mmoles/kg f r wt) Gramine Hydroxamic Acid
cv F . Union Brea " S " Celaya 79 AN MN Abyssinian 5
P o p u l a t i o n Growth Rate (day" ) Md Sg RP
ND 1.2 1.7 2.9
ND ND ND ND
0.38 0.35 0.33 0.30
0.32 0.24 0.15 0.12
0.43 0.40 0.38 0.34
ND ND ND ND
0.6 0.9 1.5 1.5
0.44 0.43 0.24 0.24
-
-
ND
1.8
0.21
-
-
ND ND
0.5 1.2
_
_
-
-
0.35 0.31
ND
3.1
-
-
0.23
ND
4.5
-
-
0.14
ND
7.3
-
-
a&Ativum
TtiAjticum
+
cv Sonka Likay Ca j erne Naofen
T . du.n.um' cv SNA-1 j j
T. CLQAtLVUm
cv Huenufen Naofen
T.
du/Lum
++
cv SNA-3
Ida. may6^ cv T125 L22
all
dead
The i n f e s t a t i o n was c a r r i e d out on 1 0 - d a y - o l d (+) or 7 - d a y - o l d (++) s e e d l i n g s i n greenhouse-grown p l a n t s . A f t e r s i x days p o p u l a t i o n growth r a t e was determined (growth r a t e = In ( N f / N i ) / A t ) . Sg, SdUzaphAA Qnaminum; Rp, RkopaloaZpkum padi; Md, ^ztopolophX.um dOihodum; ND, not d e t e c t e d .
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
132
ALLELOCHEMIC ALS: ROLE IN AGRICULTURE AND FORESTRY
Table II.
Leaf
D i s t r i b u t i o n of
Gramine and Hydroxamic A c i d s i n and Wheat T i s s u e s
Compound (mmoles/kg f r wt) Hydroxamic Gramine
Part
Complete l e a f Veins G u t t a t i o n drops Xylem exudate Epidermis
Barley
Acids
4.2 7.0 ND ND ND
0.28 ND ND ND 0.72
Gramine was d e t e r m i n e d i n b a r l e y ( c v X81-T-1031) and hydroxamic acids i n wheat (cv SNA-3) t i s s u e s . P l a n t s were grown f o r 10 days i n a greenhouse w i t h a d a y - t i m e temperature o f 25°C and a n i g h t - t i m e temperature o f 16°C. T i s s u e s were m e c h a n i c a l l y s e p a r a t e d under a microscope.
Table III.
E f f e c t s o f Gramine, DIMBOA and DIMBOA-Glucoside on SchsizapkiA QKaminum f e e d i n g on a r t i f i c i a l d i e t s
Compound
Survival (%)
None Gramine DIMBOA DIMB OA-Glucos i d e
100 10 15 50
Aphids
feeding
(%) 60 25 0
—
Reproductive Index 4.0 1.8 3.0 3.4
S u r v i v a l a f t e r 24 h and the number o f a p h i d s f e e d i n g were d e t e r m i n e d a t 4 mM compound i n the d i e t . R e p r o d u c t i v e i n d e x (number o f nymphs/ a v e r a g e number o f a d u l t s ) was d e t e r m i n e d a t 0.15 mM compound i n the diet. V a l u e s a r e t h e a v e r a g e o f t h r e e samples o f t e n a p h i d s e a c h . For r e p r o d u c t i o n s t u d i e s f i v e samples were u s e d . Standard e r r o r s were always l e s s than 10%. DIMBOA: 2 , 4 - D i h y d r o x y - 7 - m e t h o x y - l , 4 benzoxazin-3-one.
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
12.
CORCUERA ET AL.
Table IV.
133
Resistance of Cereal Crops to Aphids
E f f e c t o f Water S t r e s s i n B a r l e y P l a n t s on P r o l i n e and G l y c i n e - B e t a i n e Content and S u s c e p t i b i l i t y o f B a r l e y to
SchtzapkU Water P o t e n t i a l (-bars)
Proline (mmoles/kg
6.3 10.6 15.5
5 11 25
gnjcurnlnum
Betaine dry w e i g h t )
P o p u l a t i o n Growth (day )
Rate
- 1
0.36 0.39 0.43
57 79 126
B a r l e y seeds (cv F . Union) were germinated a t 25°C and a f t e r 6 days were s u b j e c t e d to w a t e r s t r e s s . Four days l a t e r , p l a n t s were a n a l y z e d f o r p r o l i n e and b e t a i n e c o n t e n t and t h e water p o t e n t i a l o f t h e l e a v e s was measured. At t h i s t i m e , p l a n t s were i n f e s t e d with a p h i d s and t h e i n s e c t s were c o u n t e d s i x days l a t e r .
T a b l e V.
E f f e c t s o f P r o l i n e , C h o l i n e and G l y c i n e - B e t a i n e on SchizapkiA gàaminum F e e d i n g on A r t i f i c i a l D i e t s
Compound
Survival
Aphids
(%) None Proline Choline Glycine-Betaine
93 96 72 98
± ± ± ±
Feeding
(%) 3 6 5 3
90 57 92 74
± ± ± ±
4 3 3 5
Reproductive Index 2.45 2.13 2.00 3.63
± ± ± ±
0.10 0.13 0.29 0.11
B i o l o g i c a l a s s a y s were performed w i t h 6 mM compound i n the d i e t . The r e p r o d u c t i v e i n d e x o f a p h i d s f e d w i t h 12 mM o f g l y c i n e - b e t a i n e was 5 . 1 a f t e r 72 h o f f e e d i n g . V a l u e s shown a r e the a v e r a g e ( ± s t a n d a r d e r r o r ) o f t h r e e samples o f t e n a p h i d s each. Reproduction studies were performed w i t h f i v e s a m p l e s .
Discussion C o r r e l a t i o n s between c o n t e n t o f v a r i o u s compounds i n c e r e a l s and p o p u l a t i o n growth r a t e o f a p h i d s on the p l a n t s were f o u n d . In a d d i t i o n , t h e s e compounds cause d e l e t e r i o u s e f f e c t s on a p h i d s on a r t i f i c i a l d i e t s a t c o n c e n t r a t i o n s s i m i l a r to t h o s e found i n p l a n t s . T h u s , i t i s p o s s i b l e t h a t gramine and hydroxamic a c i d s p l a y a role i n p r o t e c t i n g b a r l e y and wheat, r e s p e c t i v e l y , a g a i n s t a p h i d s . S . gKaminum f e e d s p r e f e r e n t i a l l y from phloem ( 1 7 ) . Hydroxamic a c i d s a r e more c o n c e n t r a t e d i n t h e v a s c u l a r b u n d l e s o f wheat l e a v e s than i n o t h e r t i s s u e s . Moreover, t h e s e compounds a r e n o t p r e s e n t i n
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
ALLELOCHEMICALS: ROLE IN AGRICULTURE AND FORESTRY
134
xylem exudates. Although the exact location of hydroxamic acids within the veins i s unknown, i t i s l i k e l y that these compounds protect phloem against aphid feeding. Gramine was found p r e f e r e n t i a l ly i n the epidermis of barley and was not detected i n the veins. Thus, gramine i s not found i n the main feeding s i t e (phloem) of the greenbug. Nonetheless, the feeding deterrent properties of gramine may be relevant to plant protection. A v a r i e t y of compounds may accumulate i n plants under water stress (18, 19). One of these compounds, glycine-betaine, increased reproduction rates of aphids in a r t i f i c i a l d i e t s . I t i s l i k e l y that the observed increased s u s c e p t i b i l i t y of barley to aphids may be due to glycine-betaine accumulation i n barley leaves. It i s possible that c u l t i v a r s that accumulate p r e f e r e n t i a l l y proline and other amino acids instead of glycine-betaine under stress conditions may be more resistant to aphids. Experimental Analyses of compounds. Plant tissues were homogenized i n water, adjusted to pH 3, and centrifuged at 3500 g for 15 min. The supernatant f l u i d was extracted w i t h diethyl ether (2:1 v/v, 2x) and the extract evaporated to dryness. This extract was used for quant i t a t i o n of hydroxamic acids as previously described (14). The samples for gramine analyses were frozen and macerated with 20 ml of MeOH: NHi+OH (100:1 v/v). The extract was f i l t e r e d through glass wool. Solvent and endogenous water were evaporated to dryness. The chlorophyllous residue was dissolved i n 5 ml 0.1 M HC1, and the solution f i l t e r e d (Whatman N°l paper). The aqueous f i l t r a t e was adjusted to pH 9 with concentrated NH^OH and shaken twice with chloroform (1:2 v/v). The organic phase was evaporated to dryness. Gramine was quantified i n these extracts by using Ehmann s reagent for indoles (20), as described previously (5). Proline was quantified by the method of Bates dZ aZ. (21). Glycine-betaine was quantified by the method of Grieve and Grattan (22). T
Feeding assays. Assays were performed with diets placed between two layers of Parafilm M (23). The diet was as described (24). When young aphids were used ( s u r v i v a l and feeding deterrence assays) they were 3rd and 4th-instar nymphs. Water stress treatment. Four-day-old seedlings were kept at 28°C (without i r r i g a t i o n for 48 h). Three groups of plants were then watered daily with d i f f e r e n t amounts of water for s i x days. Water potential of leaves was measured at t h i s stage (25). Acknowledgmen t This work was supported by Agency for International Development, International Foundation for Science, Fondo Nacional de Ciencias, and Universidad de Chile (N-1654).
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
12. CORCUERA ET AL.
Resistance of Cereal Crops to Aphids
135
Literature Cited 1. Tood, G.W.; Getahum, Α.; Cress, D.C. Ann. Entomol. Soc. Am.1971, 64,718. 2. Saxton, J.E. In "The Alkaloids".; Manske, R.H.F., Ed.; Academic Pressi New York, 1965; Vol. 8, p.l. 3. Gallagher, C.H.; Koch, J.H.; Moore, R.M.; Steel, J.C. Nature 1964, 204,542. 4. Corcuera, L.J. Phytochemistry 1984, 23, 539. 5. Zuniga, G.E.; Salgado, M.S.; Corcuera, L . J . Phytochemistry 1985, 24, 945. 6. Marten, G.C.; Jordan, R.M.; Hovin, A.W. Crop Sci. 1981, 21, 295. 7. Dreyer, D.L.; Campbell, B.C. Experientia 1984, 40, 224 8. Dunstan, W.R.; Henry, T.A. Philos, Trans. R. Soc. London Ser. A. 1902, 199, 399. 9. Erb, N.; Zinsmeister, H.D.; Lehmann, G.; Nahrsted, A. Phytochemistry 1979, 18, 1515. 10. Dreyer, D.L.; Reese, J.C.; Jones, K.C. J. Chem. Ecol. 1981, 7, 273. 11. Kojima, M.; Poulton, J . E . ; Thayer, S.S.; Conn, E.E. Plant Physiol. 1979, 65, 1022. 12. Klun, J.A.; Tipton, C.L.; Brindley, T.A. J. Econ. Entom. 1967 60, 1529. 13. Long, B.J.; Dunn, G.M.; Bowman, J.S.; Routley, D.G. Crop Sci. 1977, 17, 55. 14. Argandoña, V.H.; Luza, J.G.; Niemeyer, H.M.; Corcuera, L.J. Phytochemistry 1980, 19, 1665. 15. Corcuera, L . J . ; Queirolo, C.B.; Argandoña, V.H. Experientia 1985, 41, 514. 16. Argandoña, V.H.; Corcuera, L.J. Phytochemistry 1985, 24, 177. 17. Campbell, B.C.; McLean, D.L.; Kinsey, M. G,; Jones, K.C.; Dreyer, D. L. Ent. Exp. & Appl. 1982, 31, 140. 18. Hanson, A.D. HortScience 1980, 15, 623. 19. Stewart, G.R.; Larher, F. In "The Biochemistry of Plants".; Stumpf, P.K.; Conn, E.E., Ed.; Academic Press: New York, 1980; Vol. 5, p. 609. 20. Ehmann, A. J. Chromatography 1977, 132, 267 21. Bates, L.S.; Waldren, R.P.; Teare, I.D. Plant and Soil 1973, 39 205. 22. Grieve, C.M.; Grattan, S.R. Plant and Soil 1983, 70, 303. 23. Auclair, J.L. Ann. Entomol. Soc. Am. 1965, 58, 855. 24. Argandona, V.H.; Peña, G.F.; Niemeyer, H.M.; Corcuera, L.J. Phytochemistry 1982, 21, 1573. 25. Scholander, P.F.; Hammel, H.T.; Hermmingsen, E.A.; Bradstreet, E. D. Proc. Nat. Acad. Sci. USA 1964, 52, 119. RECEIVED January 3, 1986
Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
