Diversity of endophytic fungi of plants on a fairy ring in an alpine meadow on the Qinghai–Tibetan Plateau

Floccularia luteovirens is a fungus endemic to the Qinghai-Tibet Plateau, and it has an important effect on the community vegetation structures and stability of alpine meadows as it forms typical fairy rings. In this study, the diversity of culturable endophytic fungi from different plants on a fairy ring of F. luteovirens in a Qilian alpine meadow was investigated. The endophytic fungi were isolated from roots, stems, and leaves of different plants with the tissue isolation method in combined with ITS sequence analysis. The results showed that a total of 70 isolates of culturable endophytic fungi were isolated from 108 tissue blocks of 6 plant species. The total isolation rate was 64.81%, and the total colonization rate was 33.33%. Diversity and similarity analyses showed that the richness and diversity of endophytic fungi in Kobresia humilis were higher than those of endophytic fungi in other plants. The Pielou index of endophyte fungi in Oxytropis merkensis was the highest. Endophytic fungi of Potentilla anserina and Gentiana straminea as well as Leontopodium leontopodioides and O. merkensis had some similarities. The similarity of culturable endophyte fungi sorted by tissues was as follows: stems and roots > leaves and stems > leaves and roots. These endophytic fungi were dominated by Peziza ostracoderma, Stagonospora sp., and Peziza ostracoderma among different plant host and tissues. Co-occurrence network analysis revealed that K. humilis was the hub plant (eigenvector centrality EC = 1), and P. ostracoderma was the hub culturable endophyte fungus (EC = 0.75). Both plants and the associated endophytic fungi on the fairy ring of F. luteovirens are rich in diversity, and these fungi demonstrate plant and organ specificity. This study provides a new insight for evaluating plant–microbial interactions of F. luteovirens fairy rings on the Qinghai- Tibet Plateau.