Genome-Wide Comparison of Carbohydrate-Active Enzymes (CAZymes) Repertoire of Flammulina ononidis

Whole-genome sequencing of Flammulina ononidis, a wood-rotting basidiomycete, was performed to identify genes associated with carbohydrate-active enzymes (CAZymes). A total of 12,586 gene structures with an average length of 2009 bp were predicted by the AUGUSTUS tool from a total 35,524,258 bp length of de novo genome assembly (49.76% GC). Orthologous analysis with other fungal species revealed that 7051 groups contained at least one F. ononidis gene. In addition, 11,252 (89.5%) of 12,586 genes for F. ononidis proteins had orthologs among the Dikarya, and F. ononidis contained 8 species-specific genes, of which 5 genes were paralogous. CAZyme prediction revealed 524 CAZyme genes, including 228 for glycoside hydrolases, 21 for polysaccharide lyases, 87 for glycosyltransferases, 61 for carbohydrate esterases, 87 with auxiliary activities, and 40 for carbohydrate-binding modules in the F. ononidis genome. This genome information including CAZyme repertoire will be useful to understand lignocellulolytic machinery of this white rot fungus F. ononidis.本研究针对木材腐朽担子菌Flammulina ononidis开展全基因组测序，旨在挖掘与碳水化合物活性酶（carbohydrate-active enzymes, CAZymes）相关的功能基因。通过AUGUSTUS工具对总长度35,524,258 bp的从头基因组组装序列（GC占比49.76%）进行基因预测，共获得12,586个基因结构，平均基因长度为2009 bp。与其他真菌物种进行直系同源分析后发现，7051个同源基因簇至少包含1个F. ononidis基因。此外，在F. ononidis的12,586个蛋白编码基因中，有11,252个（占比89.5%）在双核真菌界（Dikarya）中存在直系同源基因；该菌株共包含8个物种特异性基因，其中5个为旁系同源基因。碳水化合物活性酶预测分析显示，F. ononidis基因组中共包含524个CAZymes编码基因，其中糖苷水解酶类228个、多糖裂解酶类21个、糖基转移酶类87个、碳水化合物酯酶类61个、辅助活性酶类87个，以及碳水化合物结合模块类40个。该基因组数据及其包含的CAZymes基因谱，将有助于解析这一白腐真菌Flammulina ononidis的木质纤维素降解机制。