Disclosure of the “Fairy” of Fairy‐Ring‐Forming Fungus Lepista sordida

A plant growth-stimulating compound, 2-azahypoxanthine (AHX) was purified from the fairy-ring-forming fungus Lepista sordida and detected in the fungus-infected soil near the growth-stimulated turfgrass roots. The molecular mechanism of action of AHX suggested that the plant developed tolerance to various and continuous stress from the environment and increased nitrogen absorption by AHX-treatment, which resulted in growth promotion.