Mating-Type System Analysis and Domestication of Paramarasmius mesosporus Based on Whole-Genome Sequencing

Paramarasmius mesosporus is a wild edible mushroom with a strong aroma and high culinary value, capable of growing at temperatures up to 36 °C. However, its domestication system and the genetic basis of its sexual reproduction remain largely unexplored. In this study, fresh fruiting bodies of P. mesosporus were collected from the rhizosphere of Imperata spp. in saline-alkali land in Hebei Province, China. The species was successfully domesticated for the first time, and fruiting bodies were harvested 7-10 days after spawning. A chromosome-level genome of the monokaryotic strain 'Q2' was assembled using whole-genome sequencing, transcriptome analysis, and Hi-C technology, with a total size of 46.57 Mb that was anchored onto 11 pseudochromosomes at a mounting rate of 95.18%. The mating-type system was identified as a typical tetrapolar heterothallic type, with the MAT A and MAT B loci located on chromosomes 2 and 10, respectively. The MAT A locus encodes HD1, HD2, MIP, and β-fg, among which tr-HD1 was found to be pseudogenized due to domain truncation. The MAT B locus comprises seven pheromone receptor genes and seven pheromone precursor genes arranged in an interspersed pattern. Based on these genomic features, a preliminary MAPK signaling pathway model was proposed to elucidate the molecular regulation of sexual reproduction. This study achieved the first artificial domestication and cultivation of P. mesosporus. systematically elucidated genomic characteristics and mating-type molecular mechanisms of this species were systematically elucidated, providing a theoretical foundation for hybrid breeding, molecular marker-assisted selection, and genetic improvement. These findings hold significant scientific and applied value for germplasm innovation and industrial development of this rare edible mushroom.