Gomez, P.,Sempere, R. N.,Aranda, M. A.,Elena, S. F.

Pepino mosaic virus (PepMV) is an emerging pathogen that causes severe economic losses in tomato crops in the Northern hemisphere. After its first identification, the new viral strain PepMV-CH2 has been isolated in several countries worldwide. In order to further understand the evolutionary dynamics of PepMV before and after PepMV-CH2 emergence, we analyzed a collection of PepMV isolates from southeastern Spain, estimating the rate of PepMV molecular evolution and the coalescence process for the effective number of PepMV infections using a Bayesian phylogenetic approach. Our results show that the rate of PepMV molecular evolution was 5.570 x 10(-3) substitutions/site/year, a value which is approximately an order of magnitude higher than the rates recently reported for other plant RNA viruses. Moreover, PepMV-CH2 was estimated to have originated in 2000, coincident with the onset of PepMV-CH2 infections in southeastern Spain, its population following now an expansion process. This further illustrates that genetic and ecological interactions among different viral strains can modulate the evolutionary dynamics of PepMV and determine its epidemiological profile.