Sexual spores in mushrooms: bioactive compounds, factors and molecular mechanisms of spore formation.

Throughout the life cycle of mushrooms, countless spores are released from the fruiting bodies. The spores have significant implications in the food and medicine industries due to pharmacological effects attributed to their bioactive ingredients. Moreover, high concentration of mushroom spores can induce extrinsic allergic reactions in mushroom cultivation workers. Therefore, it is important to study the bioactive ingredients of medicinal mushroom spores and molecular mechanisms of spore formation to develop healthcare products utilizing medicinal mushroom spores and breed sporeless/low- or high-spore-producing strains. This review summarizes the bioactive compounds of mushroom spores, the influence factors and molecular mechanisms of spore formation. Many bioactive compounds extracted from mushroom spores have a wide range of pharmacological activities. Several exogenous factors such as temperature, humidity, light, nutrients, and culture matrix, and endogenous factors such as metabolism-related enzymes activities and expression levels of genes related to sporulation individually or in combination affect the formation, size, and discharge of spores. The future research directions are also discussed for supplying references to analyze the bioactive compounds of spores and the molecular mechanisms of spore formation in mushrooms.