TITLE:
RNAi-Mediated Resistance to Cucumber Mosaic Virus (CMV) in Genetically Engineered Tomato
AUTHORS:
Valentine Otang Ntui, Kynet Kong, Pejman Azadi, Raham Sher Khan, Dong Poh Chin, Tomoko Igawa, Masahiro Mii, Ikuo Nakamura
KEYWORDS:
CMV; dsRNA; PTGS; Replicase Gene; RNAi; Tomato
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.5,
March
11,
2014
ABSTRACT:
Cucumber mosaic virus is one of the most constraints to the
production of tomato and other vegetable crops worldwide. Here, we generated an
RNAi construct containing inverted repeat of 1138 bp fragment of a partial
replicase gene of CMV-O and used it to produce transgenic tomato plants
expressing CMV-specific dsRNA of the replicase gene. Inoculation of transgenic
plants with CMV strain O discriminated three categories of plants: plants that
showed complete resistance, which were free of symptoms; highly resistant plants,
which had mild symptoms, but later recovered because new leaves that emerged
were free of symptoms; and susceptible plants, which showed severe symptoms
similar to wild-type plants. The completely resistant lines were selected and
challenged with a closely related strain, CMV-Y. Interestingly, the transgenic
plant lines either remained immune or showed high levels of resistance to the
strain. No virus could be detected in uninoculated new leaves of the resistant
lines after RT-PCR and Dot immunobinding assay (DIBA) analyses. We could show
that the resistance is correlated with post-transcriptional gene silencing
because of the production of transgenic specific siRNA.