Fungal endophyte diversity from tropical forage grass Brachiaria

Background: Microbial endophytes can be beneficial to host plants, improving resistance against biotic and abiotic stress. While beneficial fungal endophytes have been well characterised in temperate grasses, knowledge about fungal endophytes of tropical grasses is limited. Aims: To investigate fungal endophytes associated with the tropical grass Brachiaria, a genus native to Africa and highly cultivated in many tropical regions of the world. Methods: Fungi were isolated from asymptomatic tillers of nine Brachiaria species. Morphological and molecular techniques were used to investigate the taxonomic identities and phylogenetic relationships of the putative endophytes. Results: Using internal transcribed spacer (ITS) region sequence data in similarity cluster analyses at a 97% threshold, 51 operational taxonomic units (OTUs) were identified. Phylogenetic analyses of three gene regions for OTUs and type sequence data (GenBank), show the most common isolates were related to Acremonium, Fusarium, Moesziomyces, and Sarocladium. Interestingly, multiple strains belonging to the species complex Sarocladium terricola were identical to a known Brachiaria endophyte, Acremonium implicatum. Conclusion: The role and function of these as endophytes associated with Brachiaria is yet to be fully understood. However, the identification of Sarocladium and Acremonium species suggests the association, with at least some of these fungal endophytes, is mutually beneficial.