The endophyte secondary metabolite phenazine-1-carboxylic acid promotes tanshinone biosynthesis in Salvia miltiorrhiza callus

Salvia miltiorrhiza is a traditional medicinal plant widely used to treat cardiovascular and cerebrovascular diseases. Tanshinones, including cryptotanshinone, a major bioactive constituent, exhibit various pharmacological activities. Therefore, methods for efficiently increasing tanshinone production are urgently needed. Recently, plant endophytes have attracted considerable attention as novel elicitors that promote the production of valuable bioactive compounds. In the present study, we investigated the effects of secondary metabolites produced by endophytes on the biosynthesis and accumulation of tanshinones in S. miltiorrhiza. Pseudomonas chlororaphis KPUPH-SMC was identified as an endophyte capable of promoting tanshinone production, and phenazine-1-carboxylic acid (PCA) was identified as the metabolite responsible for this activity. Our transcriptome analysis further demonstrated that PCA significantly upregulated the gene expression of tanshinone biosynthetic enzymes (GGPS, CPS, and KSL1). These findings suggest that endophyte-derived secondary metabolites can be used to enhance the biosynthesis of valuable compounds in medicinal plants. This approach represents a promising strategy to improve the quality of herbal medicines.