[Potato virus Y (PVY): from its discovery to the latest outbreaks].

Potato virus Y (PVY, family Potyviridae, genus Potyvirus) is one of the most economically important viruses infecting potato. This plant virus is transmitted by aphids and is present in all potato growing areas across the world. Thanks to the steady set-up of biological, serological and molecular detection/characterization tools, PVY potato strain isolates have been classified in groups (PVYN, PVYO, PVYC, PVYZ and PVYE) or as sub-groups (PVYNTN and PVYN-W). Epidemiological data available for PVY show the recent modification of PVY group and sub-group proportions in PVY populations. This modification has led to the current prevalence of necrotic recombinant PVY isolates. In order to identify factors involved in this evolution of PVY populations, characterization of i) the molecular determinants of necrotic properties, ii) the impact of the increase of PVY virulence and aggressiveness on fitness, iii) the role of recombination in PVY evolution and iv) the genetic variability of viral populations have been carried out. The main results of this research have been combined with data already published to write the present review.