Next-generation sequencing of grapevines showing redleaf symptoms implicates a leafhopper-transmissible DNA virus in the family Geminiviridae
S. POOJARI (1), O. J. Alabi (1), V. Y. Fofanov (2), R. A. Naidu (1). (1) Washington State University, Prosser, WA, U.S.A.; (2) Eureka Genomics, Hercules, CA, U.S.A.
A graft-transmissible disease showing red veins, red blotches and total reddening of leaves, designated as grapevine redleaf disease (GRD), was observed in wine grape (<i>Vitis vinifera</i>) cultivars Merlot and Cabernet Franc. GRD significantly reduced fruit yield and affected berry quality attributes such as total soluble solids (sugars) and total extractable anthocyanins in both cultivars demonstrating negative impacts of the disease. Next-generation sequencing of high quality total RNA obtained from symptomatic and non-symptomatic leaves revealed a single-stranded DNA virus, tentatively named as Grapevine-infecting geminivirus (GiGV), and <i>Grapevine fanleaf virus</i> only in grapevines showing GRD symptoms. In contrast, <i>Grapevine rupestris stem pitting-associated virus</i>, <i>Hop stunt viroid</i>, <i>Grapevine yellow speckle viroid</i> 1, <i>Citrus exocortis viroid</i> and <i>Citrus exocortis Yucatan viroid</i> were detected in both symptomatic and non-symptomatic grapevines. GiGV was transmitted by the Virginia creeper leafhopper (<i>Erythroneura ziczac</i> Walsh). To the best of our knowledge, this is the first report of transmission of a grapevine-infecting ssDNA virus by a leafhopper species in the genus <i>Erythroneura</i>. Molecular and phylogenetic analyses indicated that GiGV represents an evolutionarily distinct lineage in the family <i>Geminiviridae</i> with genome characteristics distinct from other leafhopper-transmitted geminiviruses.
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