WINETECH Technical Yearbook 2020

Xiao, H., Shabanian, M., Moore, C., Li, C. & Meng, B., 2018. Survey for major viruses in commercial Vitis vinifera wine grapes in Ontario. Virology Journal 15, 127. Habili, N., 2015. Failure to detect grapevine rupestris stem pitting-associated virus in Iran may give a clue to the origin of this virus. Proceedings of the 18th Congress of ICVG, Ankara, Turkey, 7-11 September 2015, pp. 93-94. Gambino, G., Cuozzo, D., Fasoli, M., Pagli- arani, C., Vitali, M., Boccacci, P., Pezzotti, M. & Mannini, F., 2012. Co-evolution be- tween grapevine rupestris stem pitting-as- sociated virus and Vitis vinifera L. leads to decreased defence responses and increased

cDNA clone of another variant, related to GRSPaV-SY, was constructed in the same laboratory. But again, due to insufficient information on the genetic structure of populations of GRSPaV, mentioned earlier in this article, we do not know if the chosen variant is the most likely to be inducing RSPD in St. George. SUMMARY Grapevine rupestris stem pitting-associated virus (GRSPaV) is the most prevalent virus in vineyards worldwide. Recorded infections of GRSPaV amount to 100% of tested grapevines. Despite that the virus is well known molecularly, we still do not know much about its pathogenicity to grapevines. It is commonly believed that GRSPaV is

transcription of genes related to photosyn- thesis. Journal of Experimental Botany 63, 5919-5933. Reynolds, A.G., Lanterman, W.S. &Wardle, D.A., 1997. Yield and berry composition of five vitis cultivars as affected by rupestris stem-pitting virus. American Journal of Enology and Viticulture 48, 449-458.

a latent pathogen. However, do we really have enough data on putative severe strains of the virus that allow us to make such a statement? The author believes strongly that the industry should invest in further study of this still mysterious virus. ACKNOWLEDGEMENT The author thanks Winetech, South Africa for the financial support. REFERENCES Meng, B. & Rowhani, A., 2017. Grapevine rupestris stem pitting-associated virus. In: Grapevine viruses: Molecular biology, diagnostics and management. Meng, B., Martelli, G.P., Golino, D.E. & Fuchs, M. (eds). Springer, Cham., pp. 257-287.

For more information, contact Dariusz Goszczynski at GoszczynskiD@arc.agric.za.

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