Pomovirus

Pomovirus is a genus of plant-infecting viruses within the family Virgaviridae. These viruses are characterized by their rod-shaped particles and their unique transmission mechanism, which distinguishes them from typical insect-borne viruses. They are primarily soil-borne pathogens that cause significant economic losses in various agricultural crops.

The host range of Pomovirus includes several important crops, most notably potatoes. The most economically significant member of the genus is the Potato mop-top virus (PMTV). While the viruses primarily infect the root systems, they spread systemically throughout the plant, significantly impacting both vegetative growth and the quality of the harvested produce.

Symptoms of Pomovirus infection are often dependent on the specific strain and environmental conditions. Leaf symptoms typically include mosaic patterns, yellowing, and stunted growth. In potato tubers, the infection manifests as internal brown necrotic spots or arcs, which are often invisible from the outside but drastically reduce the commercial value and storage life of the crop.

The survival and transmission of Pomovirus are strictly tied to the soil-borne plasmodiophorid Spongospora subterranea, the causal agent of powdery scab. The virus resides inside the resting spores of this vector in the soil for many years. Favorable conditions for transmission include high soil moisture and relatively cool temperatures, which trigger the release of zoospores carrying the virus.

Management strategies focus on preventing the introduction of the virus into clean fields. Essential practices include using certified virus-free seed tubers and implementing long crop rotation intervals to reduce the resting spore population in the soil. Furthermore, controlling the vector Spongospora subterranea through improved drainage and the use of resistant crop varieties remains the most effective long-term strategy for disease suppression.