Project title
Sequencing and sequence analysis of divergent molecular variants of GVA associated with Shiraz disease

Project leader
Goszczynski, D E

Institution
ARC Plant Protection Research Institute

Team members
Jooste, A E C

Project description
Shiraz disease is highly destructive for cvs. Shiraz, Merlot, Gamay, Malbec and Viognier in South Africa. Infected plants never recover, and die within 3-5 years. First symptoms of the disease are visible in new growth. Canes show overgrown phloem and weakly developed
xylem tissue. They do not mature. SD-affected plants shed leaves much later than plants that are free of this disease.

Results indicate that GVA, a Vitivirus, is associated with Shiraz disease. The results strongly suggest that only virus variants of one molecular group are able to induce the disease. The virus is transmitted by the mealybug Planococcus ficus, a pest which is common in local vineyards. It poses a serious threat to SD-susceptible cultivars in South Africa. To know
the virus better, detailed molecular analysis of various variants of different molecular groups, mainly those associated with Shiraz disease, was initiated.

Presentation(s)
1. Goszczynski, D E, Du Preez, J, Burger, J. 2007. Molecular divergence of grapevine virus A (GVA) variants associated with Shiraz disease in South Africa. 2 May. Grapevine Virus Workshop VII, Infruitec, Stellenbosch, South Africa.

Final report
http://www.sawislibrary.co.za/dbtextimages/FinalReport130.pdf

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