Comparative genomic analysis for selected members of the Ophiostomatales: insights into biosynthetic gene clusters and CAZymes

The Order Ophiostomatales includes ecologically diverse fungi, and many are associates of bark and/or ambrosia beetles. This order includes species that cause tree diseases, and many members are sapwood staining fungi. Despite their ecological and economic importance, the genomic basis of their adaptations remains poorly understood. Here, we present annotated genome assemblies for six species (seven strains) spanning three genera within the Ophiostomatales. Genomes ranged from 21 to 32 Mb with high completeness scores. CAZyme analyses revealed broadly conserved repertoires dominated by glycoside hydrolases and glycosyltransferases, with substantial representation of lignin-and cellulose-associated enzymes and marked quantitative variation among taxa, including expanded oxidative auxiliary activity families in Ophiostoma quercus and Leptographium truncatum and a reduced profile in Ceratocystiopsis minima. antiSMASH predicted 12-19 biosynthetic gene clusters (BGCs) among the seven genomes. Rather than only broad metabolite classes, comparative analysis revealed conservation of specific secondary metabolite families, including a putative 1,8-dihydroxynaphthalene (DHN) melanin cluster present in all genomes, a conserved fujikurin-like type I polyketide synthase (T1PKS) cluster present in all genomes except L. truncatum, and an Ophiostoma-specific NRPSbased metallophore/siderophore-like cluster potentially involved in iron acquisition. The genomic data provide new insights into the metabolic capacity and potential ecological differentiation of the Ophiostomatales.