Characterization of Mycothermus thermophilus engaged in mushroom composting in Iran

The thermophilic fungus Mycothermus thermophilus is one of the most important thermophilic fungi in mushroom composting process. Thirty nine isolates of M. thermophilus were collected from nine provinces of Iran and were identified as M. thermophilus based on morphological features and ITS regions. The studied isolates significantly increased the growth of Agaricus bisporus hyphae compared to control when used in vitro situation. Also the colony morphology of the mushroom changed when it grew on the colony of M. thermophilus. While the studied thermophilic isolates were morphologically different, no diversity was observed in terms of Random Amplified Polymorphic DNA (RAPD) finger-printing. The genetically clonal population of M. thermophilus collected from Iranian mushroom composting farms was attributed to lack of sexual reproduction, similar raw materials used in compost formulations, compost temperature, and concentration of ammonia during pasteurization as selection pressures.