Identification of QTLs for Glycinin (11S) and β-Conglycinin (7S) Fractions of Seed Storage Protein in Soybean by Association Mapping

Abstract

Glycinin(11S)and β-conglycinin(7S)are major components of seed storage protein in soybean,which play important roles in the functionality of seed protein.In the present study,association mapping was used to map the QTLs(quantitative trait loci)for glycinin(11S)and β-conglycinin(7S)fractions.One hundred and sixty-six accessions from Chinese soybean minicore collection were genotyped with 134 selected simple-sequence repeat(SSR)markers.The storage protein of each accession was separated by SDS-PAGE method,and gels were scanned for individual subunits of 11S and 7S by ImageQuant TL software.The association analysis between SSR loci and protein subunit components was performed with TASSEL GLM(general linear model)and MLM(mixed linear model)programs.The results showed that,both in 2008 and 2010,fourteen SSR loci associated with the protein subunit components were screened out by GLM program,and five SSR(Satt234,Satt595,Sat_062,Satt583,and Satt291)loci by MLM program,respectively.The high variation of 7S subunits was the main reason that caused 11S/7S ratio variance.Fewer loci were detected to be associated with the protein subunits whose phenotypic variations were higher,which might be due to the more recombination incidents during the evolution of the related genes.Therefore,the LD decay distances of these genes were short,some QTLs could not be detected with limited SSR markers.The results of this study are meaningful for the marker assisted selection breeding of soybean varieties with higher protein quality.