Quantitative trait loci for β‐conglycinin (7S) and glycinin (11S) fractions of soybean storage protein

Abstract

AbstractGlycinin (11S) and β‐conglycinin (7S) are important seed storage proteins in soybean [Glycine max (L.) Merr.]. A major limitation of soybean seed storage proteins is their low levels of the sulfur‐containing amino acids, methionine and cysteine, which are important nutritional components of protein mea. Glycinin contains significantly more S‐containing amino acids than does β‐conglycinin. Thus, detection of quantitative trait loci (QTL) that govern 11S may provide marker‐assisted selection (MAS) opportunities to improve soybean total S‐containing amino acids. The objective of this study was to detect and map QTL governing 7S and 11S fractions of soybean seed storage proteins. To achieve this objective, 101 F6‐derived recombinant inbred lines (RIL) developed from a cross of N87‐984‐16 ×TN93‐99 were used. Storage proteins were extracted from all RIL and separated in 10–20% linear gradient polyacrylamide gels. Dried gels were scanned for individual subunits of storage protein with a densitometer equipped with a He−Ne laser light source. Data were converted to concentration for each subunit component and analyzed using SAS software. A significant (P<0.05) difference among genotypes was found for glycinin and β‐conglycinin. A total of 94 polymorphic simple sequence repeat molecular genetic markers were used in screening all RIL. Three QTL for glycinin (Satt461, Satt292, and Satt156) were distributed on linkage group (LG) D2, I, and L, respectively, whereas two QTL for conglycinin (Satt461 and Satt249) were distributed on LG D2 and J. Phenotypic variation explained by individual QTL ranged from 9.5 to 22%. These QTL may provide useful MAS opportunities for improvement of nutritional quality in soybean.