Biological, serological and molecular characterization of PVY strains and isolates occuring in Poland and in other countries

Potato Virus Y (PVY) is a member of the Potyviridae family – the largest plant virus family. PVY infects Solanaceae – agriculturally important species such as tobacco, potato, pepper, tomato This pathogen causes decrease in yield and quality. PVY isolates have been divided into three main strains: PVYN, PVYO and PVYC, according to the symptoms induced on tobacco and potato. PVYN isolates can be divided into two groups: PVYNW and PVYNTN. The collection of 130 potato virus Y (PVY) isolates from tobacco crops from Poland, Germany, Switzerland and Croatia, was characterized by biological, serological and molecular tools differentiating PVY strains. The correlation between especially biological and molecular tests were good but not absolute. Biological tests were carried out on Samsun H as variety particularly susceptible to PVY and VAM alike Wislica varieties as a main sources of resistance to PVY. Some isolates that caused veinal clearing symptoms on VAM variety did not cause any symptoms on Wislica variety and vice versa. Thirty seven isolates belonged to the PVYNTN group and ninety three belonged to the PVYNW group of PVYN strain. Eighteen isolates from YNTN group and sixteen from YNW were able to break resistance of VAM and/or Wislica variety. The whole genomes of thirty isolates were amplified (9700bp), and digested with three endonucleases respectively: Hin6 I, Hinf I and Sdu I. At the molecular level two clusters (YNW and YNTN) were defined by the phenetic analysis and degree of homology was determined. The most suitable enzyme for differentiation of PVY isolates was Sdu I. Homology between YNW clusters and YNTN clusters fluctuated around 50% independently of the used enzyme. PV.2