Evidences of the existence of Grapevine Pinot Gris Virus isolates showing diverse pathogenicity

Grapevine Pinot gris virus (GPGV) is a recently described trichovirus, discovered by next generation sequencing (NGS) in the cv Pinot gris, seemingly associated to a new grapevine disease. To define the aetiology of the disease, the virome of two additional Pinot gris accessions, showing or not symptoms, were analysed by NGS. Virus content consistently reproduced the already known virome with GPGV, Grapevine rupestris stem pitting virus (GRSPaV), Grapevine Rupestris vein feathering virus (GRVFV) and the two viroids Hop stunt viroid (HSVd) and Grapevine yellow speckle viroid 1 (GYSVd-1), infecting either the symptomatic or the symptomless plants. Whole genome phylogenetic analysis on seven GPGV isolates, including three isolates originating from Czech Republic and Slovak Republic and consensus sequences assembled by NGS, clearly clustered those infecting symptomatic vines. We therefore extended the analysis to two genomic regions, comprising the RNA polymerase RNA dependent domain of the replicase gene and part of the movement protein, on a group of accessions from Trentino, free from relevant viruses involved in leafroll, infectious degenerations and rugose-wood associated grapevine diseases. Maximum likelihood and Bayesian phylogenetic analyses of nucleotide sequences, proved that isolates from vines with symptoms form a clade distinct from those of symptomless vines, thus confirming studies on the whole genome. These results showed that GPGV virus populations from Trentino underwent, in the infected vines, a different evolutionary dynamic, not related with the vine variety, which selected for isolates with different pathogenicity