Pulses and grain legumes, a major source of dietary proteins, are affected by yellow mosaic and golden mosaic diseases is caused by whitefly transmitted Begomoviruses blongs to the family Geminiviridae. Four distinct species causing yellow mosaic disease on legumes have been recognised in India They are, (i) Mungbean yellow mosaic India virus (MYMIV); (ii) Mungbean yellow mosaic virus, (MYMV); (iii) Dolichos yellow mosaic virus (DYMV) and (iv) Horsegram yellow mosaic virus (HgYMV). MYMIV and MYMV are distinct from other begomoviruses. Within MYMIV and MYMV the ORF AV2 showed high degree of dissimilarity. This ORF is present only in Old World begomoviruses. The function of ORF AV2 in bipartite Old World begomoviruses is not yet resolved. Therefore, in present study, what is the role of ORF AV2 in viral pathogenesis with specific reference to replication, encapsidation and systemic movement and what is the role of ORF AV2 and ORF AV1 in whitefly transmission are the few questions, that are addressed in this book.
