Arthrographis abieticola sp. nov., A Novel Soil-Derived Fungal Species from Korea

A novel fungal strain, designated KNUF-21-045, was isolated from the rhizosphere soil beneath a Korean fir (Abies koreana) tree in Muju-gun, Jeollabuk-do, Korea. To elucidate its taxonomic status, multilocus sequence analysis was conducted using sequences of the internal transcribed spacer regions, the large subunit ribosomal RNA, and the actin gene. Phylogenetic analysis revealed that strain KNUF-21-045 clustered with Arthrographis globosa and Arthrographis arxii but formed a distinct and well-supported lineage. The strain grew optimally on oatmeal agar and tolerated temperatures from 15 to 42 °C, showing higher thermotolerance than A. globosa but slightly lower than the type species, Arthrographis kalrae. Microscopically, it exhibited hyaline, septate hyphae, simple or poorly differentiated conidiophores, and broad conidiogenous hyphae producing doliiform to cylindrical arthroconidia. Unlike A. globosa and A. arxii, the isolate produced terminal and intercalary chlamydospores, while a trichosporiella-like synasexual morph, present in A. kalrae and A. arxii, was absent. Based on its distinct phylogenetic position and unique morphological and physiological characteristics, strain KNUF-21-045 is identified as a novel species of Arthrographis, for which the name Arthrographis abieticola sp. nov. is proposed.