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

Abstract

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