nepoviruses

Nepoviruses are a genus of plant pathogenic viruses in the family Secoviridae. The name "Nepo" is derived from the first described virus in this group, the necrotic potato virus. These viruses are transmitted by a specific group of soil-dwelling nematodes, belonging to the genera Xiphinema and Longidorus. This nematode-borne transmission is a defining characteristic of nepoviruses.

Nepoviruses have a bipartite RNA genome. This means their genetic material is divided into two separate RNA molecules, typically designated RNA-1 and RNA-2. RNA-1 usually encodes proteins involved in RNA replication, while RNA-2 encodes structural proteins and proteins involved in movement within the plant. The viruses are isometric and approximately 25-30 nanometers in diameter.

Infected plants can exhibit a range of symptoms, which vary depending on the specific virus, host plant, and environmental conditions. Common symptoms include leaf mottling, mosaic patterns, ringspots, vein banding, stunting, and necrosis. Some infections can lead to significant crop losses, impacting agricultural productivity.

Control of nepoviruses relies heavily on managing their nematode vectors. This often involves using resistant plant varieties, practicing crop rotation, soil fumigation, and avoiding the introduction of infected planting material. Because the nematodes are soil-dwelling, eradication can be challenging. Worldwide, nepoviruses affect a wide array of economically important crops, including fruits, vegetables, and ornamentals.