Genetic analysis of the monopartite tomato yellow leaf curl geminivirus: roles of V1, V2, and C2 ORFs in viral pathogenesis.

摘要

The functions of the V1, V2 and C2 ORFs of tomato yellow leaf curl bigeminivirus (TYLCV) were investigated by mutational analysis. The ability of TYLCV mutants containing disrupted V1, V2 or C2 ORFs to replicate, spread and cause symptoms in Nicotiana benthamiana and tomato plants was analysed. The mutants retained the capability of autonomous replication in protoplast-derived tomato and N. benthamiana cells. V1 and V2 gene products appeared to play a role in the accumulation of single-stranded viral DNA. In contrast, none of the mutants was able to systemically infect tomato plants. This demonstrated that the V1, V2 and C2 gene products were all required for successful infection processes in the host. It is suggested that the effect of the mutation in ORF C2 was host specific since N. benthamiana plants were systemically infected, although symptom development was attenuated.