TECHNICAL SHEET no. 11 VIRUSDETECTION: VARIABILITY ANALYSIS OF PVY STRAINS GENERAL

PVY is a member of the Potyviridae, the largest plant virus family. For general information on PVY see the Web Site (life.anu.edu.au/viruses/ICTVdB/57010001.htm). Currently, three main strains of PVY are know. (i) PVY (ordinary or common strain) is widely distributed throughout the potato growning areas of the world. This strain induces mild to severe mosaic and can cause stem necrosis in some cultivars. (ii) The PVY is designed the stipple streak strain and produces systemic mosaic in some cultivars and a hypersenstive reaction in other cultivars. In tobacco, it produces the same symptoms as the PVY. (iii) PVY was recognized in the 1950’s as causing serve veinal necrosis in tobacco. I was originally described from Europe and South America. A new sub-group of PVY that causes superficial necrotic ring spots on tubers was first described in 1980. It is called potato tuber necrotic ringspot strain. The tuber symptoms develop during storage (Carnegie and van de Haar, 1999).