High genetic diversity suggests a long evolutionary history of plum pox virus-M in Turkey

Abstract

The genetic diversity and evolutionary history of the epidemic plum pox virus strain M (PPV-M) have been poorly studied. We sequenced the genomes of 69 PPV-M isolates selected from different Turkish regions. These new nearly full-length genomic sequences were analysed together with 21 previously reported Turkish sequences of the PPV-MIs clade and with 50 sequences of other PPV-M isolates collected worldwide, including four sequences of Albanian isolates. Major genomic features were maintained in all new PPV-M genomic sequences, with the highest divergence detected in the PIPO, P1 and CP proteins. Turkish PPV-M isolates displayed a high genetic diversity and grouped into two sister clades, one formed by PPV-MIs isolates only and a second clade consisting of the previously described PPV-Ma and PPV-Mb subclades. The combined diversity for PPV-M isolates (Europe, Japan and Turkey) reached to 0.022 ± 0.001, which is slightly higher than the diversity of the globally distributed PPV-D strain (0.017 ± 0.001). Likewise, the genetic diversity of PPV-M (0.020 ± 0.001) in Turkey was found to be comparable to that observed for PPV-M isolates from other countries (0.021 ± 0.001) and even marginally higher if considering partial genomic sequences that allow the inclusion of a much larger number of isolates and countries. Overall, the original distribution of PPV-MIs, which seems to be almost specific to Turkey, and the high genetic diversity of PPV-MIs and other Turkish PPV-M isolates suggest a long evolutionary history of M isolates in Turkey and position this country as a centre of diversity of PPV-M.