Development of a PCR Based Detection System for Begomoviruses from Solanaceous Vegetables

Begomoviruses are the major group of viruses belonging to the family Geminiviruses, infecting vegetable crops worldwide. In North Bengal various vegetable crops like potato and tomato is severely affected by begomoviruses and forms symptoms like leaf curl, yellowing of the leaves and stunting of the plants. Begomoviruses are single stranded circular DNA viruses known for their wide host range and rapid adaptability to new host plants. The genome of the virus constitutes of one (DNA A) or two (DNA A & DNA B) circular single stranded DNA molecules and is called monopartite or bipartite virions respectively. DNA A has been found in all old world and new world begomoviruses & harbours all the major genes needed for replication and invasion of host defence. To identify the infected plants, primers for all the six genes of DNA-A component was designed based on the available sequences of begomoviruses. DNA was isolated from both symptomatic and healthy looking plants of potato & tomato from the fields of UBKV as well as nearby villages. PCR based detection system was developed for all the sets of primers using pBIN19-DNA A as template. Among all the primers the amplification of the DNA using primers for av1, av2 & ac4 was most successful. These primers were then tested with field samples for the detection of the virus. Clear differences in the amplification pattern of symptomatic and healthy looking plants were observed.