CHARACTERIZATION OF POTATO VIRUS Y (PVY)

Potato virus Y (PVY) belongs to the Potyviridae family - the largest and economically most important group of plant viruses. Potyviruses are detected in all climatic zones and infect almost all crop plants and a lot of wild species.
Main method of protection from PVY is breeding resistant cultivars, so screening for new sources of resistance to PVY as well as screening isolates acquired from different regions of the world are very important.
Potato isolates have been divided into three main strains: PVYN, PVYO and PVYC, according to the symptoms induced on tobacco and potato. Isolates belonging to the PVYN strain induce tobacco veinal necrosis on Nicotiana tabacum, limitation of ability of assimilation and gas exchange, inhibition of water and mineral salts transport to leaves tissue. On the basis of symptoms induced on potato, PVYN isolates can be divided into two groups: the first one (PVYNW) causes mild mosaic symptoms in most potato cultivars, the other one provokes potato tuber necrotic disease, expressed as necrotic rings on tubers and is referred to as PVYNTN (necrotic tuber necrosis). PVY causes: yield and dried leaves quality decrease as well as disadvantageous increase of nitrates level on tobacco leaves. The PVYO strain (common strain) isolates induce non-necrotic mosaic on tobacco. The PVYC strain causes stipple streak symptoms on potato cultivars carrying the Nc resistance gene and non necrotic symptoms, similar to those of PVYO on Nicotiana tabacum.

Classification of PVY isolates