Subscriber access provided by Loyola University Libraries
Article
QTL mapping for glycinin and #-conglycinin contents in soybean (Glycine max L. Merr.) Yujie Ma, Guizhen Kan, Xinnan Zhang, Yongli Wang, Wei Zhang, Hongyang Du, and Deyue Yu J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.6b00167 • Publication Date (Web): 12 Apr 2016 Downloaded from http://pubs.acs.org on April 14, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 38
Journal of Agricultural and Food Chemistry
1
QTL mapping for glycinin and β-conglycinin contents in soybean (Glycine max L.
2
Merr.)
3
Yujie Ma,1 Guizhen Kan,1 Xinnan Zhang,1 Yongli Wang,2 Wei Zhang,1 Hongyang
4
Du,1 and Deyue Yu1,*
5
1
6
Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing
7
210095, China
8
2
9
China
National Center for Soybean Improvement, National Key Laboratory of Crop
Biofuels Institute, School of the Environment, Jiangsu University, Zhenjiang 212013,
10
* To whom correspondence should be addressed. E-mail:
[email protected];
11
Telephone Number: +86-25-84396410; Fax: +86-25-84396410
12 13
E-mail addresses of co-authors:
14
Yujie Ma:
[email protected] 15
Guizhen Kan:
[email protected] 16
Xinnan Zhang:
[email protected] 17
Yongli Wang:
[email protected] 18
Wei Zhang:
[email protected] 19
Hongyang Du:
[email protected] ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 2 of 38
20
Abstract: Compared to β-conglycinin, glycinin contains three to four times the
21
methionine
22
approximately 40% and 30%, respectively, of the total storage protein in soybean.
23
Increasing the soybean storage protein content while improving the ratio of glycinin
24
to β-conglycinin is of great significance for soybean breeding and soy food products.
25
The objective of this study is to analyze the genetic mechanism regulating the
26
glycinin and β-conglycinin contents of soybean by using a recombinant inbred line
27
(RIL) population derived from a cross between Kefeng No.1 and Nannong 1138-2.
28
221 markers were used to map quantitative trait loci (QTLs) for glycinin (11S) and
29
β-conglycinin (7S) contents, the ratio of glycinin to β-conglycinin (RGC) and the sum
30
of glycinin and β-conglycinin (SGC). A total of 35 QTLs, 3 pairs of epistatic QTLs
31
and 5 major regions encompassing multiple QTLs were detected. Genes encoding the
32
subunits of β-conglycinin were localized to marker intervals sat_418-satt650 and
33
sat_196-sat_303, which are linked to RGC and SGC; marker sat_318, associated with
34
11S, 7S and SGC, was located near Glyma10g04280 (Gy4), which encodes a subunit
35
of glycinin. These results, which take epistatic interactions into account, will improve
36
our understanding of the genetic basis of 11S and 7S contents and will lay a
37
foundation for marker-assisted selection (MAS) breeding of soybean and improving
38
the quality of soybean products.
39
Keywords: soybean; glycinin; β-conglycinin; QTL; epistatic QTL
and
cysteine
(sulfur-containing
amino
ACS Paragon Plus Environment
acids),
accounting
for
Page 3 of 38
Journal of Agricultural and Food Chemistry
40
Introduction
41
One-third of the global population suffers from malnutrition and disease due to
42
deficiencies in protein, vitamins and certain micronutrients,1 and enhancing the
43
nutritional quality of food is a major approach to resolving this issue. The protein
44
content is the key factor influencing the nutritional quality of grain crops, and
45
researchers have successfully increased the content of some essential amino acids in
46
crop plants using genetic engineering.2 Nonetheless, crops such as maize, rice, wheat
47
and soybean differ in protein contents, which is a complex quantitatively inherited
48
trait that is controlled by the environment, genotype, and interaction between the
49
environment and genotype.3
50
Soybean [Glycine max (L.) Merr.], one of the most important crops worldwide,
51
provides essential proteins and amino acids for humans and animals. Foods made
52
from soy, mainly soymilk and tofu, have health benefits for humans, and consumption
53
of these foods is increasing. The proportion of protein in soybean is approximately
54
35-42%,4 and based on their sedimentation coefficient at 0.5 M ionic strength,
55
soybean storage protein can be divided into 2S, 7S, 11S and 15S fractions.5 The main
56
storage proteins are 11S and 7S globulins, which account for approximately 40% and
57
30%, respectively, of the total seed storage protein. The former is glycinin, whereas
58
β-conglycinin comprises the majority of the 7S fraction.6
59
Glycinin (11S) usually exits in the form of a hexamer of 360 kDa that consists of
60
acidic and basic subunits. In contrast, β-conglycinin (7S) usually exists as a trimer of
61
α, α’ and β subunits that is approximately 180 kDa.7 Due to a lack of sulfur-containing
62
amino acids, the β subunit is very poor in nutritional quality; in addition, 11S contains
63
three to four times more methionine and cysteine than 7S. Thus, simultaneously
64
promoting the accumulation of 11S globulin and inhibiting the accumulation of 7S
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
65
globulin in soybean seed represents a way to increase the content of sulfur-containing
66
amino acids and to improve the nutritional quality of soybean. The different storage
67
proteins have different characteristics, including heating stability and gel strength in
68
soy food because of differences in their molecular structures, isoelectric points and
69
amino acid compositions.8 Indeed, the quality of tofu and soymilk is affected by
70
different levels of 11S and 7S globulins, and many studies about the relationship
71
between storage proteins and soy foods have been reported. Yang and James9 showed
72
that the absence of a particular 11S globulin polypeptide and the subsequent protein
73
subunit composition affected the texture and water-holding characteristics of tofu. Ma
74
et al.10 demonstrated that the ratio of glycinin to β-conglycinin is significantly
75
positively correlated with soymilk sensory attributes. Furthermore, Osman et al.11
76
studied the preservative action of 11S and 7S globulins on raw bovine milk and
77
deduced that 11S could be utilized as a natural preservative in raw milk if permitted.
78
Therefore, 11S and 7S determine soybean nutritional quality and functional
79
characteristics.
80
The traditional method for measuring 7S and 11S involves liquid chromatography,12
81
which has the disadvantage of being time consuming and expensive. In contrast, the
82
enzyme-linked immunosorbent assay (ELISA) used in the present study is time saving
83
and exhibits a high sensitivity for detecting 11S and 7S.13 In addition, traditional
84
breeding methods based on phenotypic selection are easily affected by environmental
85
factors, gene interactions and interactions between the genotype and environment.
86
Therefore, breeders are paying more attention to MAS, which is more rapid and
87
accurate than traditional methods, and the application of molecular markers has
88
enabled the exploration of quantitative trait loci (QTLs) for traits of yield,14
89
quality15-17 and resistance to stress.18 In general, an individual QTL can be described
ACS Paragon Plus Environment
Page 4 of 38
Page 5 of 38
Journal of Agricultural and Food Chemistry
90
as ‘major’ or ‘minor’ according to the proportion of the phenotypic variation that it
91
explains (based on the r2 value). A major QTL has a relatively large r2 value, such
92
as >10%, whereas a minor QTL has a small value, r2
