A cucumber mosaic virus mutant lacking the 2b counter-defence protein gene provides protection against wild-type strains.

摘要: Several plant virus mutants, in which genes encoding silencing suppressor proteins have been deleted, are known to induce systemic or localized RNA against themselves and other molecules containing homologous sequences. Thus, it is thought that many cases of cross-protection, infection with a mild asymptomatic mutant protects plants challenge closely related virulent viruses, can be explained by silencing. We found cucumber mosaic (CMV) the subgroup IA strain Fny (Fny-CMVΔ2b), cannot express 2b protein, cross-protects tobacco (Nicotiana tabacum) Nicotiana benthamiana disease induction wild-type Fny-CMV. However, protection most effective only if inoculation Fny-CMVΔ2b CMV occurs on same leaf. Unexpectedly, also protected TC-CMV, II not Additionally, situ hybridization revealed Fny-CMV co-exist tissues but these contain zones Fny-CMVΔ2b-infected host cells from appears excluded. Taken together, unlikely cross-protection itself sequences CMV. It more likely through either very highly silencing, competition between strains for resources.