An-Najah Staff

Declining cv. Pinot noir clone 23 plants on 3309 Couderc rootstock were observed in different vineyards in California exhibiting severe stunting, solid red leaves and rootstocks with stem necrosis-distortion. High molecular weight dsRNA of ca. 8.7 kbp was extracted from symptomatic vines, used as a template for cDNA libraries construction and sequencing and identified as a new strain of Grapevine rupestris stem pitting-associated virus designated as Pinot noir strain (GRSPaV-PN). Molecular characterization of GRSPaV-PN genome revealed that the complete nucleotide sequence was composed of 8,724 nt, excluding the poly-A tail. This strain shared nucleotide identity of 76% to 78% with other GRSPaV sequences present in the GenBank. Its genome organization included six open reading frames where its replicase gene had 76% and 85% nucleotide and deduced amino acid identities, respectively, to other GRSPaV sequences. The coat protein gene was the most conserved with nucleotide and amino acid identities of 81-88% and 91.8-95%, respectively. Limited field survey revealed that GRSPaV-PN was present mainly in Pinot noir clone 23. However, the causal nature of GRSPaVPN and 3309C stem necrosis-distortion is not known.