Location: Horticultural Crops Research2011 Annual Report
1a. Objectives (from AD-416)
Conduct genetic diversity studies among economically important grapevine viruses documented in the Pacific Northwest region.
1b. Approach (from AD-416)
It is imperative that molecular diversity studies be completed for the major viruses in the PNW region to improve our understanding of the spectrum of their variability for the development of improved diagnostic tools in order to be able to detect all the strains of a given virus and prevent their spread in PNW vineyards. Towards this goal, we will initially focus molecular diversity studies on GLRaV-2, GVA, GVB, GRSPaV, GFLV and ToRSV. We will extend these studies to other GLRaVs during the course of this project, if there is an indication of molecular variability among these viruses. Documents grant with Washington State University. Formerly 5358-22000-033-10G (8/2011).
3. Progress Report
Grapevines, due to their perennial nature, can harbor genetically diverse viruses and their strains in a single plant. Genetically diverse populations of grapevine viruses, frequently generated owing to the error-prone nature of the viral replicase, can accumulate with time due to clonal propagation of grapevine cultivars and disseminated via cuttings into new areas, causing a sustained threat to the wine grape industry in the affected areas. In this context, analyzing the spectrum of viruses and their variants from different wine grape cultivars will improve our understanding of the sanitary status of vineyards in the Pacific Northwest region and provide necessary information for the development of better diagnostic tools and sound management practices, resulting in reduced spread and economic impact of several debilitating viruses and their variants. During this year, we have documented the presence of genetically distinct variants of Grapevine leafroll-associated virus 1 (GLRaV-1) and Grapevine virus A (GVA), and four viroids (Australian grapevine viroid, Hop stunt viroid, Grapevine yellow speckle viroid-1 and Grapevine yellow speckle viroid -2) in the Pacific Northwest vineyards. This knowledge is helping us to improve the sanitary status of vineyards in the region. Genetic diversity in GLRaV-1 is enabling us to better understand the epidemiology of grapevine leafroll disease across Pacific Northwest vineyards and providing avenues for the development of robust strategies to mitigate negative impacts of the disease on sustainability of the wine grape industry in the region. The knowledge of genetic variability in GLRaV-1 and GVA obtained in this study is also benefiting grape ‘clean plant’ programs across the country in improving the sanitary status of planting materials provided to nurseries and growers. The information and resources derived from this project is giving impetus to maintain ‘clean’ plant materials in certified nurseries and Foundation Block vineyard at Prosser, WA. The project outputs have been disseminated to various stakeholders through extension and outreach programs for increased knowledge of viruses and their impacts on sustainability of the wine grape industry in the region. Methods of project monitoring included meetings, e-mail, and phone calls.