Transient expression of coding and non-coding regions of PVY confer resistance to virus infection

One of the most efficient mechanisms by which plants protect themselves from invading virusesis the specific RNA-dependent silencing pathway termed post-transcriptional gene silencing(PTGS). In this mechanism, resistance to a virus is engineered through the expression of asegment of the virus genomein transgenic plants. Potato VirusY (PVY) is one of the mostdamaging viruses of potato, infecting most cultivars and causing significant yield lossesthroughout the world. The present study was performed to compare the efficiency of threeconstruct containing different regions of 3′UTR (UR) and coat protein (CP) against PVYinfection. Expression of homologous hairpin RNA to PVY in potato plant was carried out bytransient gene expression of constructs with agro-infiltration followed by mechanical viralinfection. Results showed that successful production of siRNAs confer resistance to two PVYstrain. Comparison between transiently expressed constructs indicated that applying CP+URPVY hairpin RNA was the most efficient RNAi construct to confer resistance. Resistance wasfound to have taken the form of immunity, since no viral particle could be detected in the upperleaves as shown by ELISA assay and Northern hybridizations. To the best of our knowledge,this is the first report on the application of 3'non-coding region of PVY in conferring completeresistance against virus in potato.