Effects of chemotherapy on the elimination of various viruses and viroids from grapevine

Our experiments investigated the effects of various known chemotherapeutic agents (2-thiouracil, ribavirin and zidovudine) on grapevine for the elimination of several different viruses and viroids. Viruses and viroids were identified by small RNA HTS in the mother plants of different grapevine cultivars, and RT-PCR verified the results. Among the tested agents, ribavirin had the broadest elimination effect on most viruses. It proved to be particularly effective against GFkV, GLRaV-4, GPGV and GRSPaV, however, as a single treatment it was not able to eliminate GFLV. In our experiments, ribavirin also showed very low efficacy against GLRaV-1 and GVA viruses. The application of 2-TU caused high phytotoxicity, with only 25% efficacy against GLRaV-4 among the viruses tested. Zidovudine failed to eliminate any of the viruses we tested. However, the combination of ribavirin and zidovudine was able to eliminate GFLV, though with low efficacy (12.5%). In contrast, the combination of ribavirin and 2-TU has been shown to be very effective against GRSPaV and GPGV. Compared to ribavirin, zidovudine and 2-thiouracil did not demonstrate significant virus elimination efficacy in the case of tested viruses. In our experiments ribavirin could not remove HSVd and GYSVd-1 viroids. To the best of our knowledge, no prior studies have been published the successful use of ribavirin or other chemotherapeutic agents against GLRaV-4, and this is the first publication of a successful application of 2-TU and zidovudine against grape viruses . Overall design: virome was determined by sRNA HTSfor each grapevine plants