Alphapartitivirus roselliniae

Alphapartitivirus roselliniae is a mycovirus that infects the filamentous fungus Rosellinia necatrix, a destructive plant pathogen responsible for white root rot in numerous crops. As a double-stranded RNA virus, it resides within the fungal mycelium, essentially acting as a parasite of the fungus that causes severe economic losses in agriculture.

The primary agricultural crops affected by the host fungus Rosellinia necatrix include fruit trees like apples and peaches, grapevines, and a wide variety of woody and herbaceous plants. Since the virus specifically targets the fungus, its presence can modify the fungal growth rate, sporulation, and overall virulence, which in turn determines the severity of the disease on the host plants.

The visible symptoms of the underlying fungal infection on plants often include:

• progressive wilting and leaf chlorosis;
• formation of white fungal mycelial mats on roots;
• decay of the root cortex and vascular tissue;
• eventual death of the tree or plant due to total root system collapse.

The development and transmission of Alphapartitivirus roselliniae are facilitated by the vegetative compatibility of the host fungus. The virus spreads horizontally through hyphal anastomosis when fungal mycelia meet in the soil. Environmental factors that promote the growth of Rosellinia necatrix, such as high soil moisture and warm temperatures, also contribute to the prevalence of the virus within the fungal population.

In terms of plant protection, this mycovirus is a subject of research for biological control. By inducing hypovirulence in Rosellinia necatrix, the virus could potentially reduce the damage to orchards and crops. Preventive measures against the fungal pathogen itself remain the standard approach, emphasizing soil sterilization, the removal of infected stumps, and the application of chemical or organic fungicides to manage outbreaks.