Curing viruses in Pleurotus ostreatus by growth on a limited nutrient medium containing cAMP and rifamycin

Area of Science:

• Mycology
• Plant Pathology
• Virology

Background:

• Oyster mushroom spherical virus (OMSV) and oyster mushroom isometric virus (OMIV) cause significant fruiting body deformation in Pleurotus ostreatus.
• Mycoviral infections lead to crop loss and reduced yield in edible mushrooms.

Purpose of the Study:

• To develop an effective method for curing Pleurotus ostreatus of OMSV and OMIV infections.
• To assess the impact of mycovirus elimination on mushroom cultivation and yield.

Main Methods:

• Serial transfer of infected mycelia onto a specialized medium containing cAMP and rifamycin (cAMP-rifamycin plate).
• Five successive passages on the cAMP-rifamycin plate to eliminate mycoviruses.
• Enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) to detect and quantify mycoviruses.
• Cultivation of virus-cured and infected mycelia on mushroom compost medium.

Main Results:

• Mycelia cultured on cAMP-rifamycin plates showed a significant decrease in OMSV and OMIV levels with successive passages.
• Complete elimination of mycoviruses was achieved after five passages.
• Virus-cured mycelia produced a normal harvest of Pleurotus ostreatus.
• Virus-infected spawn failed to produce any fruiting bodies.

Conclusions:

• The cAMP-rifamycin plate method is effective for curing Pleurotus ostreatus of OMSV and OMIV.
• Eliminating mycoviruses restores the productive capacity of oyster mushroom cultivation.
• This method offers a potential solution for managing mycoviral diseases in edible mushrooms.