Abstract
Seaweed-associated endophytic fungi have recently attracted considerable attention due to their ecological significance and potential application as biological resources. Accordingly, research efforts to isolate and characterize fungal endophytes from marine macroalgae have accelerated. This study aimed to isolate and identify endophytic fungi from two brown algae, Sargassum thunbergii and S. muticum, collected from intertidal zones in Tongyeong and Pohang, Korea. Identification was performed based on morphological characteristics and multilocus phylogenetic analyses using ITS, LSU, TEF1, TUB2, and RPB2 gene sequences. As a result, three previously unrecorded fungal species in Korea were identified: Neopyrenochaeta telephoni, Trichoderma cyanodichotomum, and Microascus intricatus. This study provides detailed descriptions of their morphological features and phylogenetic relationships. These findings contribute to a better understanding of fungal diversity associated with brown algae in Korea and highlight the potential significance of endophytic fungi in marine ecosystems.