Genome-wide Identification and Expression Profile Analysis of Laccase Family Genes in the Hypsizygus marmoreus

Laccase exists widely in plants and fungi. It is a copper-containing polyphenol oxidase that can degrade lignin, oxidate, and phenolic substances, inhibit heterophytes, promote fruiting body formation, and improve the quality of mushrooms. In this study, 18 laccase genes were identified from the whole genome of a white strain (HM62) of Hypsizygus marmoreus, and the mapping, structure, and evolution of laccase genes were analyzed at the whole genome level, while the spatiotemporal expression was evaluated at different developmental stages. The laccase genes mainly distributed on chromosomes 1, 2, 3, 4, 6, 9, and 10, and 9 genes were clustered linearly on chromosome 6, indicating gene doubling. Phylogenetic tree analysis showed that the laccase gene family was divided into three subfamilies. The spatiotemporal expression analysis of the laccase gene family showed that HmLac09 and HmLac10 were highly expressed in different periods and might be involved in lignin degradation and fruit body formation, respectively. The expression levels of HmLac02, HmLac05, HmLac08, and HmLac17 genes in gray or gray and white heterozygous strains were higher than those in white strains, which might be related to the difference in lignin decomposition in gray strains, and one of the factors leading to different growth rates. The present study investigated the characterization of the H. marmoreus laccase gene family, extending our understanding of laccase mediated fruiting body development and growth rate mechanisms in this fungi.