Development of N gene mediated resistance in tomato against GBNV

Bud blight is an emerging viral problem in tomato. Bud blight affected plants reacted positively to polyclonal antiserum of Groundnut Bud necrosis Virus (N gene). TN-Co, UP-Ka, MH-Pu and MH-Ra isolates could infect 13 out of 27 plant species tested belonging to Solanaceae, Leguminoase and Malvaceae. The nucleocapsid protein (N) and movement protein (NSm) genes were cloned and sequenced using GBNV specific primers. N gene of the tomato Tospovirus isolates shared 97-100% amino acid sequence identity with GBNV (type isolate). Further the N gene among GBNV isolates originating from tomato and other hosts and different locations was highly conserved (96-99%), suggesting their common origin. Similarly the NSm genes of tomato Tospovirus isolates from different locations shared 98% amino acid sequence identity with GBNV (type isolate) and were highly conserved (96-98%). N gene from GBNV TN-Co isolate was used as transgene to confer resistance in tomato. Nine transgenic lines Co3S1, Co3S2, Co3S12, PRS1, PRS3, PRA1, PRA2, PRA4 and PRA5 were Southern positive. None of the T0 lines showed symptoms upon mechanical inoculation with TN-Co isolate