miR403a and SA Are Involved in Mediated Antiviral Defenses Against TMV Infection in .

RNAi (RNA interference) is an important defense response against virus infection in plants. The core machinery of the RNAi pathway in plants include DCL (Dicer Like), AGO (Argonaute) and RdRp (RNA dependent RNA polymerase). Although involvement of these RNAi components in virus infection responses was demonstrated in , their contribution to antiviral immunity in , a model plant for plant-pathogen interaction studies, is not well understood. In this study, we investigated the role of gene against TMV (Tomato mosaic virus) infection. Silencing of by transient expression of an hpRNA construct recovered GFP (Green fluorescent protein) expression in -silenced plant, demonstrating that participated in RNAi process in . Expression of was transcriptionally induced by both MeSA (Methylsalicylate acid) treatment and TMV infection. Down-regulation of gene by amiR- transient expression compromised plant resistance against TMV infection. Inhibition of endogenous miR403a, a predicted regulatory microRNA of , reduced TMV infection. Our study provides evidence for the antiviral role of against a family virus TMV in , and SA (Salicylic acid) mediates this by induction of expression upon TMV infection. Our data also highlighted that miR403a was involved in TMV defense by regulation of target gene in .