Multi-gene phylogeny and morphological study reveal three new species of Ophiostoma Syd. and P. Syd. (Ascomycota, Ophiostomatales) from oak trees in South Korea

During a survey of putative fungal pathogens infecting oak trees in the Republic of Korea, fungal isolates exhibiting morphological characteristics of Ophiostoma species were consistently collected from natural wounds on oak trees. Based on morphological characterization and phylogenetic analyses, including single-gene phylogenies of ITS, TUB2 , TEF1-α , and RPBII sequences, alongside a multi-gene phylogeny of ITS, TUB2 , and TEF1-α , it was revealed that the fungi collected resided in a distinct lineage. In this regard, these novel species of Ophiostoma are described here as Ophiostoma guttiferum sp. nov ., O. querceti sp. nov ., and O. subcorticale sp. nov ., based on their unique morphology and phylogenetic placement within the O. ulmi species complex. This study examines and compares them with phylogenetically related taxa, presenting detailed descriptions of the isolates along with molecular data. Consequently, the detection of these fungal lineages strongly suggests further undocumented Ophiostoma taxa remain to be discovered nationwide.