Cross-species amplification and genetic variation among blackgram genotypes using SSR markers developed from mungbean DNA sequence scaffolds harbouring putative resistance genes

The cross species amplification of 97 mungbean derived resistance gene-SSR markers were investigated for diversity analysis in a set of 44 blackgram genotypes. A total of 68(70%) SSR markers showed amplification in blackgram. Our of 68 markers, thirty randomly selected markers were used to study the genetic variation among 44 blackgram genotypes varying for yellow mosaic disease (YMD) and powdery mildew disease (PMD) reaction. Thirty SSR primers collectively amplified 90 alleles in blackgram with an average of three alleles/locus. The polymorphic information content (PIC) of the SSR markers ranged from 0 to 0.86 with an average of 0.43. Cluster analysis based on UPGMA neighbour-joining method grouped the 44 genotypes into seven clusters. The genotypes NDU-1 and PU-19 were observed to be highly dissimilar with similarity coefficient of 0.27 in comparison to other genotypes. YMD and PMD resistant and susceptible genotypes could be differentiated by three (MRGSSR 12, MRGSSR 56, MRGSSR 77) and four SSR markers (MRGSSR12, MRGSSR 32, MRGSSR56 and MRGSSR65), respectively. Two of these markers viz.,  MRGSSR12 and MRGSSR56 were mutually effective in differentiating YMD and PMD resistant genotypes. These were located in mungbean scaffolds JJMO01002369 and  JJMO01001477 and exhibited homology with TMV resistance protein N and DNA damage-repair/toleration protein DRT100, respectively.