Diversity and bioactive potential of endophytic fungi from Nothapodytes foetida, Hypericum mysorense and Hypericum japonicum collected from Western Ghats of India

Endophytic fungi are major contributors to fungal diversity and an important component of plant microbiota. Plants growing in biodiversity hotspots and having ethnobotanical utility are often explored for the presence of endophytic fungi with bioactive potential. Western Ghat mountains of India are one of the ten famous biodiversity hotspots in the world. Hence, in the present study, we investigated the diversity of endophytic fungi associated with tissues of Nothapodytes foetida (a tree), Hypericum mysorense (a shrub) and Hypericum japonicum (a herb) collected from forests of Western Ghats with emphasis on diversity of endophytic fungi harbored in different tissues of three plants and their antimicrobial and free radical scavenging activities. A total of 298 isolates belonging to 31 genera were isolated along with dark septate and sterile fungi. All isolates belonged to Dothidiomycetes, Eurotiomycetes and Sordariomycetes of the phylum Ascomycota. Most frequent colonizers were Penicillium, Aspergillus, Fusarium, Gliocladium, Cladosporium, Trichoderma, Colletotrichum, and Pestalotiopsis. Endophytes showed neither any host preference nor any dominance of a single species. Ethyl acetate extracts of 39 endophytic fungi exhibited antimicrobial activity against one or more pathogens, of which the activity of Bionectria ochroleuca NOTL33, Chaetomium globosum HYML55, Alternaria brassicae HYMS01, Aspergillus sp. HYML56 was prominent against most of the pathogens tested. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radicals were effectively quenched by the ethyl acetate extracts of 28 isolates and 34 isolates, respectively. This study is the first of its kind in H. mysorense and H. japonicum, and not only describes the endophytic diversity of these plants but also emphasizes the bioactive potential of endophytic isolates for future use in agricultural, pharmaceutical and industrial applications.