Diversity of endophytic fungi associated with Taxus wallichiana (Himalayan Yew) from Eastern, Nepal

Endophytic fungi, integral components of plants, are increasingly recognized for their potential to produce novel bioactive compounds with applications in pharmaceuticals, agriculture, and industry. In this research, we investigated the taxonomic and molecular diversity of culturable endophytic fungi associated with the leaves and bark of Taxus wallichiana which is a key source of the anticancer drug Taxol. A total of 75 isolates yielded 32 distinct morphotypes were identified through morphological traits and Internal Transcribed Spacer (ITS) rDNA sequence analysis. The isolates belonged to the phyla Ascomycota and Basidiomycota, with Ascomycota strongly dominant, driven primarily by genus Annulohypoxylon.Diversity analyses revealed variation among sampled T. wallichiana trees with sample TKTN04 showing the highest species richness and TKTN05 the lowest. Shannon (H’) and Simpson (1–D) indices indicated high diversity in TKTN04 and TKTN03, with TKTN03 also exhibiting perfect evenness (J = 1.00). Low Jaccard similarity (<0.3) suggested minimal overlap among trees. Principal Component Analysis explained 44% of total variation. Overall, the significant spatial variation and strong dominance of specific Ascomycota lineages underscore the untapped potential of the Himalayan T. wallichiana mycobiome as a reservoir for bioactive natural product discovery.