New Records of Endophytic Fungi Isolated from the Seaweed Sargassum thunbergii in Jeju, Korea: Sclerostagonospora cycadis and Aspergillus occultus

Seaweed-associated endophytic fungi remain largely unexplored despite their potential as source of novel bioactive metabolites. In this study, we isolated endophytic fungi from the brown alga Sargassum thunbergii collected in Jeju, Korea. Two previously unrecorded species were identified through morphological characteristics and phylogenetic analysis based on ITS, LSU, TUB, and CaM sequences: Sclerostagonospora cycadis and Aspergillus occultus. Detailed morphological descriptions and phylogenetic relationships of each species are provided. This study expands the known diversity of marine endophytic fungi in Korea and is expected to contribute to understaning their ecological association with seaweeds.