Beneficial Effects of Endophytic Fungi from the Anoectochilus and Ludisia Species on the Growth and Secondary Metabolism of Anoectochilus roxburghii .

Endophytic fungi possess favorable effects on their host plants, including disease-resistance improvement, secondary metabolite induction, and growth promotion. It is therefore a promising and sustainable strategy to utilize endophytic fungi for the quality improvement of medicinal herbs or important crops. In our study, a collection of 277 strains of endophytic fungi were isolated from and orchids. Two strains J162 and J211 can be symbiotically cocultured with the tissue culture seedlings of , a popular medicinal and edible plant in southern China. Both strains can significantly enhance the biomass of and induce the biosynthesis and accumulation of its active ingredients, including flavonoids, kinsenoside, and polysaccharides. J162 and J211 were further identified as and based on multilocus phylogenetic analysis. Immunocytochemical staining indicated that J162 and J211 mainly colonized the intercellular gap of xylem parenchyma cells of roots without obvious harm. In addition, quantitative real-time polymerase chain reaction showed that the expression of three growth-related genes, namely, uracil phosphoribosyl transferase, amino acid transmembrane transporter, and maturase K, were significantly altered in plants when treated with J162 and J211. In conclusion, the two strains are highly beneficial microbial resources for the growth and accumulation of active ingredients of in agricultural cultivation.