Evidence of seed transmission of dolichos yellow mosaic virus, a begomovirus infecting lablab-bean in India.

Yellow mosaic disease in field bean caused by begomoviruses belonging to the family Geminiviridae is a major threat to the cultivation of crop in South India. Appearance of bright yellow mosaic symptom in emerging seedlings in farmers field was suggestive of seed transmission of the begomovirus associated with the disease which was investigated in the present study. The begomovirus causing yellow mosaic disease was identified as dolichos yellow mosaic virus (DoYMV) and the presence of DoYMV in matured seeds was confirmed by DAS-ELISA with OD value up to 3.268. In PCR with DoYMV specific primer (DoYMV-CP) the virus was detected in different parts of the seeds viz., seed coat, endosperm and embryo. In embryo the virus was detectable up to 100 per cent followed by endosperm (69.23%). When the non symptomatic leaves of 30 days old grow-out test plants were subjected to DAS-ELISA, the virus was detected up to 46.6%. This is the first evidence of seed transmission of DoYMV.