Flavonoids, which are abundant in plants, are recognized for their antioxidant and anticancer roles in clinical applications. However, little is known about the molecular basis of flavonoid biosynthesis in fungi. In this study, we found that inclusion of leachate of Korshinsk peashrub (Caragana korshinskii) in the fermentation medium increased the total flavonoid content of the edible fungus Auricularia cornea by 23.6% relative to that grown in a control medium. Combined transcriptomic and non-targeted metabolomic analysis of the flavonoid biosynthesis pathway in A. cornea illustrated that there are important metabolites in the phenylpropanoid, coumarin and isoflavonoid biosynthesis pathways. In addition, we found that certain homologous genes encode phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO) and chalcone isomerase (CHI) in these biosynthesis pathways. These results, in this study, provide a new line for studying the regulation of flavonoid production in edible fungi.

The microbial community plays a crucial role in plant health and sustainable agricultural development by influencing plant physiology and development. This study aimed to explore the biocontrol potential of Bacillus subtilis A9, an endophytic bacterium isolated from Morchella sextelata, against rot disease caused by Lecanicillium aphanocladii. Metagenomic and metabolomic analyses were conducted on Morchella sextelata samples sprayed with B. subtilis A9 and a control group sprayed with LB medium. Metagenomic sequencing revealed that B. subtilis A9 significantly altered the microbial community structure and functional composition of Morchella sextelata, enriching genes related to biofilm formation, arginine and proline metabolism, and sulfur metabolism. Metabolomic analysis indicated significant upregulation of stress-resistant metabolites such as L-proline, ketoleucine, and pelargonic acid. Integrated multi-omics analysis demonstrated a strong correlation between the microbial community structure and the metabolomic profile, suggesting that B. subtilis A9 may be related to the disease-resistance response in the Morchella sextelata microecosystem. These findings provide a theoretical basis for the biological control of Morchella sextelata rot disease and support the development of green biocontrol strategies.