The potato mop‑top virus (PMTV) is a plant pathogenic virus that infects Solanum tuberosum (potato). It belongs to the genus Pomovirus within the family Virgaviridae and is characterized by a tripartite, positive‑sense, single‑stranded RNA genome.
Taxonomy and structure
- Family: Virgaviridae
- Genus: Pomovirus
- Species: Potato mop‑top virus (PMTV)
The virion is non‑enveloped and filamentous, typical of members of Virgaviridae. Its genome consists of three RNA segments that encode proteins involved in replication, movement, and capsid formation.
Transmission and epidemiology
PMTV is transmitted soil‑borne via the fungal‑like protozoan Spongospora subterranea (the causative agent of powdery scab). The vector infects potato tubers and roots, allowing the virus to spread as the pathogen propagates in the soil. The virus was first identified in the United Kingdom in 1966 by Calvert and Harrison and has since been reported in major potato‑growing regions worldwide, including Europe, North America, and parts of Asia.
Symptoms and impact
Infected plants may exhibit stunted growth, leaf chlorosis, and, most notably, necrotic lesions on tubers that resemble a “mop‑top” appearance. Yield losses and reductions in tuber quality can be economically significant, especially in cultivars that are highly susceptible.
Management
Control strategies focus on limiting the presence of the vector and using tolerant or resistant potato varieties. Seed certification programs in some countries do not require routine testing for PMTV, making cultural practices—such as planting certified seed, crop rotation, and selecting tolerant cultivars—critical for disease management. No commercially available cultivar is completely resistant, but varying degrees of tolerance have been identified.
Research and significance
PMTV serves as a model for studying plant‑virus interactions, particularly the mechanisms of vector‑mediated transmission and multipartite genome organization. Ongoing research aims to develop more effective diagnostic tools and to breed potato varieties with enhanced resistance to the virus.