Survey on sanitary status of native Vitis vinifera varieties in Georgia

In September 2013, surveys on typical symptoms of grapevine viruses were carried out in three collections representing the autochthon Georgian Vitis vinifera L. germplasm, located in Saguramo (Shida Kartli region), Shumi and Kindzmaraulis (Khaketi region). Leaf samples were collected from 37 plants of 12 white and 13 red berry varieties showing symptoms, as leaf rolling and chromatic alterations, with different severity. Total RNAs were extracted from leaves and PCR-based reactions were performed with specific primer pairs to identify Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine leaf roll-associated virus 1, 2, and 3 (GLRaV-1, GLRaV-2 and GLRaV-3), Grapevine virus A (GVA), and Grapevine pinot gris virus (GPGV). Obtained results revealed the prevalence of GRSPaV (mainly strains of groups 2a and 2b, associated with vein necrosis of 110R, identified in 29 out of 37 plants) and GLRaV-3 (identified in 26 out of 37 plants). Surprisingly, GLRaV-1 and GVA were detected in few plants (three out of 37), always in mixed infection with GLRaV-3. As expected, GLRaV-2 was identified only in two plants. Moreover, GPGV, a Trichovirus recently reported in Europe and Korea, was detected in 7 plants of six varieties (Goruli mtsvane, Khikvi, Mtsvane kviteli, Saperavi pachkha, Tavkveri, Korkaula), always in mixed infection with GRSPaV, GLRaV-3 and GVA. As the response of the Georgian grapevine varieties to the pathogens has not been described accurately, further investigation will be needed to determine the typical symptoms associated with grapevine viruses and to evaluate their potential effects on yield and wine quality.