Analysis of seed storage protein pattern: a method for studying genetic variation and diversity among vigna genotypes

Abstract

A method based in protein gel electrophoresis was employed in order to improve the analysis of genetic relationships among populations of Vigna. It has been used to estimate genetic divergence among 34 improved varieties, five local land races, one wild progenitor of mungbean (Vigna sublobata) and a land race of urdbean.In total, 20 polypeptide bands were resolved for seed storage proteins (albumin and globulin) by SDS-PAGE. The electrophoregrams revealed 11 and nine polypeptide bands for albumin and globulin respectively that have exhibited an array of polymorphism both in quality and quantity of bands. The varieties, C. No. 3 and C. No. 36 had similar protein type for albumin and globulin seed protein fraction, but differed in thickness of bands. Mayurbhanj local (an urdbean local cultivar) and TCR 213 (a wild progenitor of mungbean) had absence of a globulin band GL9 (27.5kd) and GL8 (30.2kd) respectively, but such bands were present in all other accessions leading to serve as molecular marker(s) for their identification. Mutants of mungbean differed in polypeptide banding pattern as compared to their parents indicating the mutation of genes in multigene families for seed storage protein expression. Cluster analysis revealed high genetic diversity of Keonjhar local, Pant M-5, OUM 75-1 and Mayurbhanj local(urdbean) from rest of the genotypes. The results obtained support the idea that seed storage protein analysis can be successfully applied to phylogenetic analysis of Vigna genotypes.