Gene expression of the white-rot fungus Lenzites gibbosa during wood degradation.

Abstract

To determine the wood degradation mechanism and its key genes and biological processes of Lenzites gibbosa, we sequenced 15 transcriptomes of mycelial samples under woody environment at 3, 5, 7, and 11 d (D3, D5, D7, and D11) and nonwoody environment (control). All the transcripts were annotated as much as possible in eight databases to determine their function. The key genes and biological processes relating to wood degradation were predicted and screened. The expression of 11 key genes during wood degradation after 5 d of sawdust treatment was detected by quantitative polymerase chain reaction (PCR). A total of 2069 differentially expressed genes (DEGs) were obtained in 10 differential groups. Comparing wood with nonwood treatment condition, the key genes were those participating in oxidation-reduction process, they were oxidoreductase and peroxidase genes and their regulator genes; these genes mainly focused on the three biological processes of carbohydrate metabolism, lignin catabolism, and secondary metabolite biosynthesis, transport, and catabolism. The mostly enriched subcategories in molecular function were oxidoreductase activity, peroxidase activity, and heme binding in Gene Ontology (GO) annotation. One cellulose and hemicellulose degradation pathway and seven pathways related to lignin-derived aromatic compound degradation or the later degradation of lignin were found. In conclusion, during the process of L. gibbosa growing on wood, gene expression at the transcriptional level indicated that lignin catabolism and hyphal growth were promoted, but the metabolism of carbon and carbohydrates including cellulose in lignocellulose in overall trend was inhibited to some extent. The results have important reference value for the study of degradation mechanism of wood white rot.