Recombinants of PVY Strains Predominate Among Isolates from Potato Crop in Poland

Abstract

Recombinants of PVY Strains Predominate Among Isolates from Potato Crop in Poland 282 Potato virus Y (PVY) isolates collected from potato crops in northern and central Poland from 1995 to 2009 were characterized by serological and biological assays. From these, 112 isolates collected from 2006 to 2009 were additionally analyzed by one-step triplex Reverse Transcription-Polymeraze Chain Reaction (RT-PCR). Recombinants of PVY strains predominate among the isolates tested. Using one-step triplex RT-PCR most PVYN-Wi isolates were classified as subgroup PVYNWi-P and most PVYN and/or PVYNTN isolates as the recombinant PVYNTN strain. A recombinant PVYNTN isolate (12/94) and two additional PVYN and/or PVYNTN isolates were not detected by one-step triplex RT-PCR. Twelve isolates were identified as the PVYO strain but PVYN, non-recombinant PVYNTN and PVYC strains were not found. Serological and biological assays of 144 isolates of PVYN-Wi strain showed that 100 isolates were the expected PVYO serotype with vein necrosis (VN) symptoms on tobacco. However, 10 isolates of the PVYNWi-P subgroup exhibited vein clearing (VCl) on tobacco and 2 isolates of the PVYNN242 subgroup unexpectedly exhibited as the PVYN serotype. All the isolates of PVYN-Wi strain induced severe local lesions (LL) on Chenopodium amaranticolor. Out of 126 isolates of PVYNTN strain tested, 76 were typical PVYN serotype with VN on tobacco, but their reactions on C. amaranticolor were different: 13 isolates did not show symptoms, 23 isolates induced weak, and 40 isolates induced severe LL. The remaining isolates of PVYN-Wi, PVYN and/or PVYNTN or PVYO were serologically PVYN and PVYO positive or exhibited unpredictable serological and biological reactions.