Diversity, biocontrol, and growth promotion potential of culturable endophytic fungi isolated from root, shoot, and leaf of wild Phoebe bournei Yang across seasons

Abstract

Endophytic fungi were isolated from Phoebe bournei (Hemsl.) Yang, and their diversity and antimicrobial and plant-growth-promoting activities were investigated. Of the 389 isolated endophytic fungi, 88.90% belonged to phylum Ascomycota and 11.10% to phylum Basidiomycota. The isolates were grouped into four taxonomic classes, 11 orders, 30 genera, and 45 species based on internal transcribed spacer sequencing and morphologic analysis. The host showed a strong affinity for the genera Diaporthe and Phyllosticta. The diversity of the fungi was highest in autumn, followed by spring and summer, and was lowest in winter. The fungi exhibited notable tissue specificity in P. bournei, and the species richness and diversity were highest in the root across all seasons. Five isolates showed antimicrobial activity against eight plant pathogens and reduced the incidence of leaf spot disease in P. bournei. Additionally, nine biocontrol isolates showed plant-growth-promoting activity, with five significantly promoting P. bournei seedling growth. This is the first report on the endophytic fungi of P. bournei and their potential applicability to plant disease control and growth promotion.