Sclerotia Formation of Phlebopus portentosus under Natural and Artificial Conditions

Phlebopus portentosus is a favorite wild, edible mushroom in the tropical region of China and northern Thailand. P. portentosus is the only bolete in the Boletales order that has been commercially cultivated. Sclerotia produced by the mushroom are often found in its natural habitats and cultivated media. These sclerotia play a key role in its life cycle. However, the regularity and growth characteristics of the sclerotium are unknown. In this paper, the whole process of birth, growth, death and rebirth of the sclerotium of P. portentosus under natural and lab conditions is reported for the first time. Sclerotium formation in nature is due to environmental stress, such as drought or low temperature. The less rainfall, the more sclerotia are produced. It appears that a lower temperature can also initiate sclerotium formation; however, the relationship between sclerotium formation and temperature is not as clear as that between sclerotium formation and rainfall. Under artificial conditions, the sclerotium formation of P. portentosus is related to the fungus’ physiological maturation. The presence of sclerotia is always accompanied by the exudation of liquid droplets on the colony. The results of this study should provide a platform for research on the importance of sclerotium formation in the life cycle of P. portentosus.