Genetic diversity of potato virus Y (PVY): sequence analyses reveal ten novel PVY recombinant structures

The potato virus Y (PVY) complex includes five non-recombinant strains and a growing number of recombinants. Up to now, the bulk of these PVY recombinants were found to be composed of genome segments coming from only two "parental" genomes, PVY^O and PVY^Eu-N, with a small minority including segments from other parents, e.g. PVY^C, PVY^NA-N, and a segment of the recombinant strain PVY-NE11. Here, comprehensive analyses of 396 whole genomes of PVY isolates from 34 countries and a variety of hosts revealed 28 isolates to be rare or novel recombinants. When subjected to a thorough recombination analysis, these 28 PVY isolates were found to represent 25 poorly sampled PVY recombinant structures, ten of which had not been recognized previously. Nine of the ten novel structures carried parental sequences from PVY^NA-N or PVY-NE11 strains recombined with PVY^O and PVY^Eu-N sequences, while seven of the new structures contained sequences from three different parents. The number of known PVY recombinant patterns now stands at thirty six. These recombinant structures present a challenge for PVY strain typing, but may shed light on interactions between PVY and host resistance genes.