Auxiliary rapid identification of pathogenic and antagonistic microorganisms associated with Coptis chinensis root rot by high-throughput sequencing.

Root rot reduces the yield and medical quality of C. chinensis (Cc). Previous studies of Coptis root rot focused on the identification of pathogens and the rhizosphere microbial community composition. The present study aimed to identify potential pathogenic and antagonistic microorganisms associated with root rot based on a high-throughput sequencing technique to prevent this disease. Healthy and diseased Cc in the endosphere and rhizosphere from the same field were collected to investigate the differences in microbiome composition and function. The results showed that the composition and function of microbes were different. The numbers of animal pathogens, soil saprotrophs, plant saprotrophs, and wood saprotrophs in the endosphere of diseased Cc were higher than those in the healthy endosphere and were dominated by Phaeosphaeriaceae, Cladorrhinum, Fusarium, Exophiala, and Melanommataceae. Fusarium, Volutella, Cladorrhinum, Cylindrocarpon, and Exophiala were significantly enriched in the endosphere of the diseased plants. Co-occurrence network analysis showed that Bacillus was negatively correlated with Fusarium, Volutella, and Cylindrocarpon, indicating that Bacillus may be antagonistic microorganisms. To verify the sequencing results, F. solani and F. avenaceum were isolated and verified as pathogens, and 14 Bacillus strains were isolated, which displayed an apparent suppression effect against the two pathogens on PDA medium and detached roots. The strategy of high-throughput sequencing has the potential for the comprehensive identification of pathogenic and antagonistic microorganisms for plant disease. These results provide research ideas and microbial resources for future studies on mitigating or preventing root rot damage to Cc.