Transcriptome and Hormonal Analysis of Agaricus bisporus basidiomes Response to Hypomyces perniciosus Infection

Agaricus bisporus (Lange) Imbach is the most widely cultivated mushroom in the world. Agaricus bisporus wet bubble disease is one of the most severe diseases of white button mushrooms and is caused by the fungal pathogen Hypomyces perniciosus. The pathogen causes a drastic reduction in mushroom yield due to malformation and deterioration of the basidiomes. However, the mechanism of the button mushroom's malformation development after infection with H. perniciosus remains obscure. Therefore, to reveal the mechanism of A. bisporus malformation by H. perniciosus, the interaction between the pathogen and host was investigated in this study using histopathology, physiological and transcriptomic analyses. Results show that irrespective of the growth stages of A. bisporus basidiomes infected with H. perniciosus, the host's basidiome with malformed basidiomes and enlarged mycelia and basidia indicated that the earlier the infection with H. perniciosus, the more the malformation of the basidiomes. Analyzing physiological and transcriptomic results in tandem, we concluded that H. perniciosus causes malformation development of A. bisporus mainly by affecting the level of phytohormones (N6-isopentenyladenyladenosine, cis-Zeatin and N6-(daelta2-lsopentenyl)-adenine) metabolism of the host's fruiting bodies, rather than by use of toxins. Our findings revealed the mechanism of the button mushroom's malformation development after infection with H. perniciosus, providing a reference for developing realistic approaches to control mushroom diseases. Our results further clarified the interaction between A. bisporus and H. perniciosus and identified the candidate genes for the A. bisporus wet bubble disease resistance breeding. Additionally, our work provides a valuable theoretical basis and technical support for studying the interaction between other pathogenic fungi and their fungal hosts.