The potato virus Y
Presentation
| Potato virus Y (PVY, type-member of the Potyvirus genus) is one of the most economically important plant pathogens. First reported in the 1930s in potato, PVY is now distributed worldwide. PVY present a filamentous flexuous particle of 700 nm in length and 20 nm in diameter. This plant virus is transmitted by at least 70 aphid species in a non-persistent manner and infects several crop species belonging to the family Solanaceae. The viral genome that consists of a single-stranded, positive-sense RNA molecule encodes a single polypeptide, which is cleaved into nine products. According to the host, they were originally collected from PVY isolates, have been classified into four different strains corresponding to potato, pepper, tobacco and tomato strains. The extensive biological, serological and molecular variability of PVY isolates supports the complex classification of PVY isolates into groups (based mainly on symptoms induced in indicator hosts and on abilities to overcome selected resistance sources) and putative variants (grouping isolates with particular properties). Using these criteria, three common PVY potato strain groups (PVYN, PVYO and PVYC) and two variants (PVYNTN and PVYN-W within the PVYN group) have been identified. PVYN and PVYO isolates are responsible for high yield losses in potato and tobacco; corresponding to losses of up to 40–70% in the case of PVYO infecting potato and 14–59% in PVY-infected tobacco crops. These yield losses can reach 100% in the case of veinal necrosis disease induced by PVYN isolates in tobacco. PVY became, for potato growers, a major agronomical problem in the 1980s with the emergence and then the spread of the PVYN-W and PVYNTN variants. Indeed, PVYN-W isolates, characterized as PVYO group members by serological tools, present biological properties close to those of PVYN isolates while PVYNTN variants possess the capacity to induce the potato tuber necrotic ringspot disease (PTNRD). Given these facts, the analyses of genetic and biological variability PVY isolates in potato crops has always been an important scientific challenge. |
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Sources : INRA et www.plantdepommedeterre.org
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Writing:
Alexandra Blanchard
Creation date: 26 September 2007
Update: 11 July 2008
