Genome-wide identification and expression profiles of the superoxide dismutase (SOD) genes in Lentinula edodes

The superoxide dismutase (SOD) enzymes are a group of key enzymes involved in oxidative stress defense and play a significant role in organismal growth and development. The SOD gene family has been identified in many plants, animals, and some fungi but not in the economically important edible mushroom Lentinula edodes. In this study, members of the SOD gene family of L. edodes were identified and analyzed using bioinformatic methods. Three proteins containing signature SOD domains were identified in each of the two monokaryotic strains SP3 and SP30 of L. edodes, and all six proteins belonged to the major Fe/Mn-SOD type. Phylogenetic analysis revealed that these LeSOD genes were classified into two subtypes, with members of each type sharing the same conserved motifs. Transcriptome data of mycelia grown under different conditions showed that LeSOD1 was significantly up-regulated under heat stress, while LeSOD2 was significantly up-regulated under hydrogen peroxide stress. Together, the genomic and transcriptomic analyses suggest that LeSOD1 and LeSOD2 are key genes for L. edodes to respond to abiotic stresses. This study provides a foundation for understanding both the roles of the SOD gene family and the molecular mechanism by which L. edodes responds to heat and oxidative stresses.