New acquisition about the role of Colomerus vitis in the transmission of Grapevine Pinot gris virus.

Grapevine Pinot Gris Virus (GPGV) is a new Trichovirus associated with symptoms of chlorotic mottling and leaf deformations in grapevine (Vitis vinifera). Preliminary studies indicate that GPGV can be transmitted by the eriophyid mite Colomerus vitis (Pagenstecher). Acquisition and transmission by an arthropod vector is central to the infection cycle of the majority of plant pathogenic viruses. In this work we carried out transmission trials and analyzed the virus to detect which strains of the GPGV is transmitted by C. vitis. Specimens of C. vitis were collected in GPGV symptomatic vineyards and mites were extracted from infested buds and leaf erinea. A pool of 10 mites for sample was subjected to RT-PCR to ascertain the presence of GPGV. Total RNAs of C. vitis were extracted and GPGV detection was carried out by RT-PCR and real-time PCR (RT-qPCR). To detect GPGV strains, PCR products were both sequenced and compared with GenBank, and digested by BAM HI. Transmission trials were carried out under controlled conditions (22°C, 70 % relative humidity, 16:8 L:D) using GPGV infected buds and leaf erinea infested by C. vitis. Buds and leaf erinea were placed onto GPGV free vines. After transmission trials the appearance of erinea was observed and each plant was analyzed with the above described methods to assess the presence of GPGV and qualify the strain. Both strains of GPGV were found in C. vitis as well as in the GPGV positive vines obtained by transmission trials