High-throughput sequencing detection and molecular characterization of viral diseases of grapevine (Vitis vinifera L.) and their elimination by thermotherapy and meristem tissue cultureMiljanić, Vanja (Avtor) Štajner, Nataša (Mentor) grapevineVitis viniferaHTSviromediagnosisgenetic diversitythermotherapymicrograftingWe studied the virome of preclonal candidates obtained after mass selection of grapevines using HTS technology. Nine viruses (GFLV, GLRaV-3, GRSPaV, GFkV, GSyV-1, GRVFV, GRGV, GPGV, and RBDV) and two viroids (HSVd and GYSVd-1) were identified. GRGV, GRVFV, and GSyV-1 were detected for the first time in Slovenia. All in silico predicted viruses and viroids were validated with RT-PCR and Sanger sequencing. We obtained a comprehensive insight into genetic diversity, phylogeny and co-infections. In the second part of the dissertation, we investigated the viruses and viroids elimination efficacy by in vivo thermotherapy and in vitro meristem tip micrografting. Heat therapy was performed at 36-38 °C for at least six weeks. Meristem tips (0.1-0.2 mm) were aseptically isolated and micrografted onto the sectioned, etiolated hypocotyls of Vialla (Vitis labrusca × Vitis riparia). The overall regeneration rate was low (8.53%). The higher regeneration rate was observed in the white varieties. The regenerated plants were micropropagated several times. The sanitation status was checked with RT-PCR. All viruses were completely eliminated, while the elimination of viroids was less successful (39.2% for HSVd and 42.6% for GYSVd-1). It is important to emphasize that plant growth regulators (hormones) were not used. In the third part of the thesis, we studied the virome of samples that were not part of the clonal selection process. We detected: GLRaV-1, GLRaV-2, GLRaV-3, GFkV, GRVFV, GRSPaV, GFLV (in association with its satellite RNA), GPGV, GV-Sat, HSVd, and GYSVd-1. GV-Sat was also detected for the first time in Slovenia. We developed a protocol for high-throughput validation of in silico predicted infections, including various combinations of viruses, viroids, and satellites.20222022-10-19 07:15:20Doktorsko delo/naloga142063sl