EVALUATION OF THE RESISTANCE AGAINST BEGOMOVIRUSES IMPARTED BY THE SINGLE-STRANDED DNA BINDING PROTEIN VirE2

Begomoviruses belonging to the family Geminiviridae are plant-infecting distinct single-stranded (ss)-DNA viruses causing significant reductions in crop yield. VirE2 is ss-DNA binding protein and can be used to obtain resistance against ss-DNA viruses. We have utilized VirE2 from Agrobacterium tumefaciens to get resistance against begomoviruses. Resistance was evaluated against both mono- and bipartite begomoviruses using Agrobacterium-mediated inoculation technique. Nicotiana benthamiana plants were inoculated with infectious clones of Cotton leaf curl Kokhran virus (CLCuKoV)/Cotton leaf curl Multan betasatellite (CLCuMuB) and Tomato leaf curl New Delhi virus (ToLCNDV) alone as well as along with VirE2 construct. The plants inoculated with infectious clones showed typical virus symptoms while delayed or milder symptoms were observed in plants inoculated with viruses along with VirE2 construct, furthermore, 68% resistance against CLCuKoV/CLCuMuB and 56% against ToLCNDV was observed. The visual observations were confirmed through PCR and Southern hybridization. The results have also shown that VirE2 gene was able to reduce the replication of both viruses. Therefore, inhibition of viral DNA replication by VirE2 could be adapted to protect economically important crops against begomoviruses.