potyviruses

Potyviruses are a large genus of plant viruses in the family Potyviridae. They are positive-sense single-stranded RNA viruses that infect a wide range of herbaceous and woody crops. Potyviruses are among the most economically important plant pathogens worldwide, causing mosaic patterns, yield losses, and quality reductions.

Genomes are about 9 to 10 kilobases in length and encode a single large polyprotein that is cleaved into several functional proteins by viral proteases. The proteolytic processing yields proteins involved in replication, movement, and silencing suppression. A genome-linked viral protein, VPg, is linked to the 5' end in many species, and the coat protein forms the virus particle.

Transmission is typically by aphid vectors in a non-persistent manner, meaning virions are acquired and transmitted during brief probes and do not circulate within aphids. Several aphid species, such as Myzus persicae, contribute to spread. The host range is broad, including potato, pepper, tobacco, legumes, and stone fruits; Plum pox virus (PPV) is a well-known potyvirus affecting stone fruits.

Symptoms vary by species and host but commonly include mosaic or mottling, leaf distortion, necrotic or chlorotic rings, stunting, and reduced yield. Disease diagnosis relies on serology (ELISA) and molecular methods (RT-PCR). Management relies on resistant varieties where available, vector management, sanitation to limit spread, roguing of infected plants, and use of cross-protection strategies in some crops.

Potyvirus taxonomy is maintained by the International Committee on Taxonomy of Viruses. The type species is Potato virus Y (PVY). The genus contains dozens of species, with ongoing additions as new viruses are discovered and characterized.