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POSTERS: New and emerging diseases

Virus survey in California reveals the presence of novel vitiviruses infecting grapevine
Alfredo Diaz-Lara - University of California-Davis. Kamyar Aram- University of California, Maher Al Rwahnih- University of California-Davis, Deborah Golino- University of California, Reid Brisbane- Foundation Plant Services

Virus species in the genus Vitivirus (family Betaflexiviridae) are associated with the etiology of rugose wood disease in grapevine. This genus was named after Vitis spp., the host of Grapevine virus A, the type species. Recently, through the application of high-throughput sequencing (HTS), five novel Vitivirus-like viruses were discovered and named grapevine virus G, H, I, J and L (GVG, H, I, J and L); GVJ and GVL were identified in the USA. Given the history and importance of the well-known vitiviruses, grapevine viruses A, B and D, we targeted novel vitiviruses in an extensive survey of ca. 2,500 samples to evaluate their prevalence in different California grapevine populations. As a result, all five novel vitiviruses were detected in several grapevine selections via reverse transcription PCR (RT-PCR) and later confirmed by Sanger sequencing; specifically, 4, 36, 16, 1 and 15 samples tested positive for GVG, H, I, J and L, respectively. This study represents the first report of GVG, GVH and GVI in the USA. The variability between GVG, GVH, GVI and GVL isolates was investigated using distance matrices and phylogenetics. Finally, co-infection by novel and previously known vitiviruses was also evidenced by RT-PCR.