Characterization and functional analysis of microbial communities in Bletilla striata

The connection between the traditional Chinese medicinal herb Bletilla striata and microorganisms is still not well understood. Our study aimed to uncover the structure and diversity of the fungal and bacterial communities associated with B. striata. Bioinformatics, biocontrol and biochemical experiments were carried out. In terms of relative abundance of the top 15 phyla of microbial species, tenericutes in stems (58.74%) and roots (39.36%) showed the highest relative abundance, while cyanobacteria in leaves presented the most (64.53%). At the genus level, there were 32 genera of bacteria detected in three tissues. Sphingomonas showed relative abundances in leaves (41.54%) and stems (22.68%), while Paraburkholderia showed the highest relative abundance in roots (20.87%). In contrast, the dominant genera of the fungi were Melampsora (28.55–43.61%) and Cryptococcus (6.1-25.56%) among the top 15 genera of fungi species. Twenty microorganisms were obtained from roots, stems, and leaves and isolated, which also confirmed the results of the bioinformatics analysis. The isolated Bacillus velezensis exhibits the capability to enhance both the growth and nutrient accumulation of B. striata. Additionally, B. velezensis, along with its fermentation products, contributes to the improvement of antioxidant enzyme activity. Notably, there are variations in the species and abundance of microflora present in the leaves, stems, and roots of B. striata at both the phylum and genus levels. The components of the microbial flora that were isolated and identified align with the results obtained from bioinformatic analyses. It is noteworthy that B. velezensis exerts a positive impact on the increase in yield of B. striata. This work provides important insights into B. striata-associated microorganisms that are essential for promoting growth and disease resistance by revealing the complex structure and variety of fungal and bacterial communities.