New fungal endophytes in Bromus valdivianus Phil. diversity, ecological function, and their relationship with the host in the grasslands of southern Chile

Endophytic fungi play a crucial role in plant-host interactions; however, the endophytic diversity associated with Bromus valdivianus Phil.(pasture brome), a forage species of agronomic importance, remains largely unexplored.In this study, we determined the diversity and ecological function of endophytic fungi in B. valdivianus in southern Chile.Seeds and leaves were collected from wild plants and cv.Bronco in La Araucana, Los Ros, and Los Lagos Regions during 2022-2023.Isolates were grown on agar water and potato dextrose agar media, followed by morphological characterization and molecular identification through polymerase chain reaction amplification of the internal transcribed spacer region (rDNA-ITS), -tubulin, and elongation factor 1-. Nineteen species of endophytic fungi were identified: 18 from the phylum Ascomycota and one from the phylum Mucoromycota.Fusarium proliferatum was the most abundant species, followed by Trichoderma harzianum.Five species of interest were identified: Chaetomium subaffine, Beauveria bassiana, Penicillium sanguifluum, T. harzianum, and T. koningiopsis.A phylogenetic analysis revealed tissue-specific colonization patterns, with 80.5% infection in leaf samples and 19.5% in seeds.Functional predictions based on FUNGuild database determined five trophic modes distributed across nine ecological guilds.Location, ecological role (endophytes, phytopathogens, saprotrophs), and morphological variables explained 57.1% of species distribution.This research provides the first comprehensive characterization of endophytic fungi in B. valdivianus, laying the foundations for understanding plant-endophyte interactions and applications in sustainable grassland management in southern Chile.