Abstract

RNA interference (RNAi) is a conserved RNA-mediated gene regulatory mechanism, which plays important role in plant growth, development and as an antiviral defence system in plants. RNAi are mainly classified into three major categories, small interfering RNAs (siRNAs), microRNAs (miRNAs) and piwi interacting RNAs (piRNAs). Trans acting siRNAs (tasi RNA) is a novel group of endogenous siRNA whose biogenesis requires an initial microRNA mediated cleavage of precursor RNA. In this study two tasiRNA based silencing vectors were constructed along with their mutated counterparts to generate resistance against Tomato leaf curl New Delhi virus (ToLCNDV). The accumulation of tasiRNA was abolished when mutated constructs were used. Transgenic tomato and tobacco plants were raised and most of the lines showing resistance against ToLCNDV were found to accumulate high amount of tasiRNA. In plants, four TAS families have been reported till date and they are known to be involved in different functions. In tomato two TAS families has been reported which are TAS3 and TAS5. This study indicated the presence of a novel TAS4 locus in tomato whose presence is confirmed by corresponding miRNA in tomato plant. This was done by analysing the high throughput sequencing data from healthy and virus infected tomato where the corresponding tasiRNA was also detected.