Identification of glycinin and beta-conglycinin subunits that contribute to the increased protein content of high-protein soybean lines.

Seed protein concentration of commercial soybean cultivars calculated on a dry weight basis ranges from approximately 37 to 42% depending on genotype and location. A concerted research effort is ongoing to further increase protein concentration. Several soybean plant introductions (PI) are known to contain greater than 50% protein. These PIs are exploited by breeders to incorporate the high-protein trait into commercial North American cultivars. Currently, limited information is available on the biochemical and genetic mechanisms that regulate high-proteins. In this study, we have carried out proteomic and molecular analysis of seed proteins of LG00-13260 and its parental high-protein lines PI 427138 and BARC-6. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis revealed that the high-protein lines accumulated increased amounts of beta-conglycinin and glycinins, when compared with Williams 82. High-resolution two-dimensional electrophoresis utilizing pH 4-7 and pH 6-11 ampholytes enabled improved resolution of soybean seed proteins. A total of 38 protein spots, representing the different subunits of beta-conglycinin and glycinin, were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. High-protein was correlated with an increase in the accumulation of most of the subunits representing beta-conglycinin and glycinin. Comparisons of the amino acid profiles of high-protein soybean lines revealed that the concentration of sulfur amino acids, a reflection of protein quality, was not influenced by the protein concentration. Southern blot analysis showed the presence of genotypic variation at the DNA level between PI 427138 and BARC-6 for the genes encoding group1 glycinin, beta-conglycinin, Bowman-Birk inhibitor (BBI), and the Kunitz trypsin inhibitor (KTI). LG00-13260 inherited the allelic variants of the parental line PI 427138 for glycinin, beta-conglycinin, and KTI, while BBI was inherited from the parental line BARC-6. The results of our study indicate that high-seed protein concentration is attributed to greater accumulation of specific components of beta-conglycinin and glycinin subunits presumably mediated by preferential expression of these genes during seed development.

[1]  D. I. Neece,et al.  QTL associated with seed protein and oil concentration from three sources of high protein in soybeans , 2007 .

[2]  J. Bennett,et al.  Assessment of indigenous Nepalese soybean as a potential germplasm resource for improvement of protein in North American cultivars. , 2006, Journal of agricultural and food chemistry.

[3]  W. Wiebold,et al.  Effect of six decades of selective breeding on soybean protein composition and quality: a biochemical and molecular analysis. , 2006, Journal of agricultural and food chemistry.

[4]  James E. Specht,et al.  Fine mapping of a seed protein QTL on soybean linkage group I and its correlated effects on agronomic traits , 2006 .

[5]  A. Saxton,et al.  Quantitative trait loci controlling sulfur containing amino acids, methionine and cysteine, in soybean seeds , 2006, Theoretical and Applied Genetics.

[6]  Chenping Xu,et al.  Comparison of protein solubilization methods suitable for proteomic analysis of soybean seed proteins. , 2005, Analytical biochemistry.

[7]  M. Hajduch,et al.  A Systematic Proteomic Study of Seed Filling in Soybean. Establishment of High-Resolution Two-Dimensional Reference Maps, Expression Profiles, and an Interactive Proteome Database1[w] , 2005, Plant Physiology.

[8]  H. Krishnan.  Engineering Soybean for Enhanced Sulfur Amino Acid Content , 2005 .

[9]  David A. Sleper,et al.  Registration of S97-1688 Soybean Germplasm Line High in Protein Content and Resistant to Soybean Cyst Nematode , 2004 .

[10]  James E. Specht,et al.  The Seed Protein, Oil, and Yield QTL on Soybean Linkage Group I , 2003 .

[11]  David Durham,et al.  The United Soybean Board's Better Bean Initiative: Building United States Soybean Competitiveness from the Inside Out , 2003 .

[12]  R. Yaklich.  beta-Conglycinin and glycinin in high-protein soybean seeds. , 2001, Journal of agricultural and food chemistry.

[13]  J. Wilcox,et al.  Interrelationships among Seed Quality Attributes in Soybean , 2001 .

[14]  H. Krishnan.  Biochemistry and Molecular Biology of Soybean Seed Storage Proteins , 2000 .

[15]  E. Cober,et al.  Developing High‐Protein, High‐Yield Soybean Populations and Lines , 2000 .

[16]  L. Schwartz,et al.  Two-dimensional electrophoresis of liver proteins: characterization of a drug-induced hepatomegaly in rats. , 2000, Electrophoresis.

[17]  K. Chase,et al.  Genetics of soybean agronomic traits: I. Comparison of three related recombinant inbred populations , 1999 .

[18]  J. W. Burton,et al.  Registration of ‘Prolina’ Soybean , 1999 .

[19]  J. Orf,et al.  Protein, oil, and yield of soybean lines selected for increased protein , 1998 .

[20]  C. Sneller,et al.  Genetic diversity among soybean plant introductions and North American germplasm , 1998 .

[21]  R. Shoemaker,et al.  Mapping QTL for Seed Protein and Oil Content in Eight Soybean Populations , 1997 .

[22]  J. W. Burton,et al.  Genetic Diversity Patterns in North American Public Soybean Cultivars based on Coefficient of Parentage , 1996 .

[23]  J. Wilcox,et al.  Backcrossing High Seed Protein to a Soybean Cultivar , 1995 .

[24]  C. Sneller.  Pedigree Analysis of Elite Soybean Lines , 1994 .

[25]  T. Carter,et al.  Genetic Base for North American Public Soybean Cultivars Released between 1947 and 1988 , 1994 .

[26]  W. Schapaugh,et al.  Amino acid profile of high seed protein soybean , 1994 .

[27]  R. Leffel.  Registration of high-protein soybean germplasm lines BARC-6, BARC-7, BARC-8, and BARC-9 , 1992 .

[28]  E. E. Hartwig.  Registration of Soybean High‐Protein Germplasm Line ‘D76‐8070’ , 1990 .

[29]  S. Barker,et al.  Soybean beta-conglycinin genes are clustered in several DNA regions and are regulated by transcriptional and posttranscriptional processes. , 1989, The Plant cell.

[30]  J. W. Burton,et al.  Evaluation of recurrent restricted index selection for increasing yield while holding seed protein constant in soybean , 1989 .

[31]  B. Scallon,et al.  Characterization of the glycinin gene family in soybean. , 1989, The Plant cell.

[32]  W. Fehr,et al.  Transfer of High Seed Protein to High-Yielding Soybean Cultivars 1 , 1987 .

[33]  J. W. Burton,et al.  Quantitative genetics: results relevant to soybean breeding , 1987 .

[34]  R. Jorgensen,et al.  Ribosomal DNA spacer-length polymorphisms in barley: mendelian inheritance, chromosomal location, and population dynamics. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[35]  J. W. Burton,et al.  Methionine Concentration in Soybean Protein from Populations selected for Increased Percent Protein 1 , 1982 .

[36]  J. W. Burton,et al.  Recurrent Selection in Soybeans. II. Selection for Increased Percent Protein in Seeds 1 , 1979 .

[37]  K. Shibasaki,et al.  Major proteins of soybean seeds. Subunit structure of .beta.-conglycinin , 1978 .

[38]  K. Shibasaki,et al.  Major proteins of soybean seeds. Reconstitution of .beta.-conglycinin from its subunits , 1978 .

[39]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[40]  U. K. Laemmli,et al.  Cleavage of structural proteins during , 1970 .