Molecular and morphological characterization of nine new Gnomoniopsis species (Diaporthales, Gnomoniaceae): Genomic insights into evolution and phylogeny

Gnomoniopsis comprises parasitic, endophytic, and saprophytic fungi. Since its establishment, this genus has presented considerable taxonomic challenges owing to extensive morphological overlap among species, rendering traditional classification systems that rely predominantly on phenotypic characteristics no longer applicable. To resolve the current taxonomic confusion and clarify the species diversity, phylogenetic relationships, and genomic adaptive characteristics of Gnomoniopsis , the present study was carried out. In this study, the internal transcriptional spacer (ITS), translation extension factor 1-α ( tef1 ), and partial beta-tubulin ( tub2 ) were analyzed and combined to observe morphological characteristics of Gnomoniopsis . The isolates were identified from chestnut ( Castanea ), Embelia vestita , tea ( Camellia sinensis ), and other hosts in Sichuan Province, as well as from Quercus species and partial leaf rot from Fujian Province. Nine new species, namely G. xiaoheijiangensis sp. nov ., G. embeliae sp. nov ., G. yunvfengensis sp. nov ., G. quercus sp. nov ., G. ledongensis sp. nov ., G. yonganensis sp. nov ., G. conghuaensis sp. nov ., G. loropetali sp. nov ., and G. qixiensis sp. nov ., were obtained. Phylogenomic analysis based on 7,942 orthologous proteins’ clusters revealed distinct species boundaries within Gnomoniopsis . Phylogenomics has thus effectively resolved the ambiguous phylogenetic relationships in this genus. This work identifies nine previously undescribed Gnomoniopsis species, clarifies the species diversity and conserved genomic characteristics within the genus, and lays a foundation for subsequent taxonomic analyses of Gnomoniopsis .