Fungal Endophyte from Lithophytic Plants Native to Basalt Coastal Dunes in Gimnyeong and Woljeong, Jeju Islands, Korea

This study aimed to establish a fungal symbiont culture collection for coastal dune conservation and determine the diversity and distribution of endophytic fungi in rocky coastal dunes at Gimnyeong and Woljeong in the Jeju Islands. Endophytic fungi can promote plant growth and induce systemic resistance to environmental stress and infections in host plants. The native plant species thriving in these habitats play a crucial role in preventing coastal erosion. A total of 138 fungal endophytes were isolated from two plant groups: basalt-dwelling lithophytes (83 isolates) and sandy soil-dwelling halophytes (55 isolates). The host plants belonged to nine orders, 11 families, 14 genera, and 14 species. Molecular identification and phylogenetic analysis based on internal transcribed spacer (ITS) regions classified the isolates into six fungal classes, 11 orders, 15 families, and 22 genera. The dominant classes were Sordariomycetes (51.45%), Eurotiomycetes (26.09%), Dothideomycetes (18.84%). The dominant genera were <i>Penicillium</i> (33.58%), <i>Fusarium</i> (16.79%), <i>Aspergillus</i> (15.33%), and <i>Talaromyces</i> (10.22%). Endophyte diversity, as measured by Shannon's diversity index (2.131), was higher in basalt-habitat lithophytes than in sandy soil-dwelling halophytes. However, no distinct pattern was observed in the variation of endophyte diversity or richness across plant life cycles (annual, perennial, or biennial species).