Genotypic Analysis for Retrieval of MYMV Resistant Progenies from Certain Crosses of Mungbean [Vigna radiata (L.) Wilczek]

The present investigation was conducted to study the nature of inheritance of MYMV among intra-specific crosses among three MYMV susceptible and five MYMV resistant genotypes of green gram. The molecular screening and hotspot evaluation is carried out in fifteen F1 progenies and 8 F2 families, respectively. The yellow mosaic-affected leaf samples gave positive results with MYMIV specific primer pairs YFP1/YRP1 and YFP2/YRP2 amplified fragments having size of 704bp and 648 bp, respectively. Coat protein gene sequence analysis revealed that the identified virus is homologous to MYMV. The inheritance study based on F2 data indicated the ratio of MYMV resistant plants and susceptible plants showed a good fit to expected 3:1 (Susceptible: Resistant) suggesting a typical monogenic recessive gene governing resistant reaction to MYMV besides resting the susceptibility from the susceptible parents.

Genetic diversity and molecular evolution of Ornithogalum mosaic virus based on the coat protein gene sequence

Ornithogalum mosaic virus (OrMV) has a wide host range and affects the production of a variety of ornamentals. In this study, the coat protein (CP) gene of OrMVwas used to investigate the molecular mechanisms underlying the evolution of this virus. The 36 OrMV isolates fell into two groups which have significant subpopulation differentiation with an FST value of 0.470. One isolate was identified as a recombinant and the other 35 recombination-free isolates could be divided into two major clades under different evolutionary constraints with dN/dS values of 0.055 and 0.028, respectively, indicating a role of purifying selection in the differentiation of OrMV. In addition, the results from analysis of molecular variance (AMOVA) indicated that the effect of host species on the genetic divergence of OrMV is greater than that of geography. Furthermore, OrMV isolates from the genera Ornithogalum, Lachenalia and Diuri tended to group together, indicating that OrMV diversification was maintained, in part, by host-driven adaptation.