Genomic variability in Potato potyvirus Y (PVY): evidence that PVYNW and PVYNTN variants are single to multiple recombinants between PVYO and PVYN isolates

• Published in: Archives of virology 2002-02, Vol.147 (2), p.363-378
• Main Authors: GLAIS, L, TRIBODET, M, KERLAN, C
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Epidemiology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Genomes; Microbiology; Molecular immunology; Techniques; Viruses
• ISSN: 0304-8608; 1432-8798

Fourteen Potato virus Y (PVY) isolates representative of PVYO, PVYN, PVYNTN and PVYNW groups were characterised at genomic level. Restriction fragment length polymorphism study (RFLP) of each gene of these isolates and sequencing of the first 2700 nucleotides of two PVYNW isolates were performed. A mosaic structure was revealed in PVYNW and PVYNTN genomes, which showed either PVYO or PVYN-like sequences, depending on the particular gene. Indeed, starting from the 5[variant prime]-end, these isolates showed a switching, from PVYN- to PVYO-like sequence, in the HC-Pro C-terminal region. Reversion to PVYN-like sequence was also revealed in the NIa N-terminal area of PVYNTN isolates, followed by a switching back to a PVYO-like sequence in the CP gene. Lastly, some PVYNW isolates showed a switching from PVYO- to PVYN-like sequence in the P1 N-terminal part, thus separating our PVYNW isolates into two subgroups. All these apparent recombination events were shown by statistical analysis. Comparison of molecular traits with pathogenic properties of our isolates suggested that the HC-Pro protein is involved in induction of necrosis in tobacco leaves, and the NIa, NIb and/or CP protein in necrosis in potato tubers. Nevertheless, multiple recombination events observed in the PVYNTN genome may play a role in the latter phenomenon.