Marine ecosystems are important in discovering novel fungi with interesting metabolites that have shown great potential in pharmaceutical and biotechnological industries. Seagrasses, the sole submerged marine angiosperm, host diverse fungal taxa with mostly unknown metabolic capabilities. They are considered to be one of the least studied marine fungal habitats in the world. This review gathers and analyzes data from studies related to seagrasses-associated fungi, including taxonomy and biogeography, and highlights existing research gaps. The significance of the seagrass–fungal associations remains largely unknown, and current understanding of fungal diversity is limited to specific geographical regions such as the Tropical Atlantic, Mediterranean, and Indo-Pacific. Our survey yielded 29 culture-dependent studies on seagrass-associated endophytic and epiphytic fungi, and 13 miscellaneous studies, as well as 11 meta-studies, with no pathogenic true fungi described. There is a significant opportunity to expand existing studies and conduct multidisciplinary research into novel species and their potential applications, especially from understudied geographical locations. Future research should prioritize high-throughput sequencing and mycobiome studies, utilizing both culture-dependent and -independent approaches to effectively identify novel seagrass-associated fungal taxa.

During our ongoing research on seagrass-associated fungi in Kalpitiya, Puttalam Lagoon, Sri Lanka, ten endophytic fungal strains have been isolated from healthy leaves, roots, and rhizomes of Enhalus acoroides . A surface sterilization method was used for the isolation of fungi. Pure cultures obtained were induced to sporulate. Phylogenetic analyses based on multi-gene regions (ITS, LSU, SSU, rpb 2, and tef 1 -α ) were carried out for species identification. Neodevriesia zeylanica Wijayaw. et al. and Neooccultibambusa zeylanica Wijayaw. et al. are introduced as novel species, along with two new country and host records, i.e., Neodevriesia saximollicula D.S.Paiva and Thalassodendromyces purpureus Vohník & Réblová. Two strains have been confirmed as Halophilomyces hongkongensis Xiao Wang et al. (nom. invalid), the type species of Halophilomyces Xiao Wang et al. (nom. invalid). Halophilomyces hongkongensis (based on the newly isolated strains) has been validated and provided with a new name, Halophilomyces zeylanica Wijayaw. et al., along with the designation of a new holotype and ex-type, respectively.