Abstract
Due to the low yield of tanshinones and their analogues in Salvia miltiorrhiza, there are all kinds of stimulation strategies having been applied to improve tanshinones output in plant tissue cultures. Endophytic fungi have formed various different relationships with their host plants withstanding host and environmental factors, including symbiotic, mutualistic, commensalistic, and parasitic. Thus we take the assumption that endophytic fungi may be an emerging microbial tool used to promote secondary metabolism, which will promote the production of active compounds through endophyte-based biology method. Our study therefore aimed to examine the effects of live endophytic fungus Chaetomium globosum D38 and its elicitors on the accumulation of tanshinones in hairy root cultures of Salvia miltiorrhiza. C. globosum D38 mainly colonized in the intercellular gap of xylem parenchyma cells of S. miltiorrhiza hairy root, during long term co-existence without any toxicity against S. miltiorrhiza hairy root. Moreover, both of the live fungus and its mycelia extracts could induce the production of tanshinones, in special dihydrotanshinone I and cryptotanshinone. The effects of mycelia extracts were much stronger than that of the live fungus on tanshinones synthesis, which increased the transcriptional activity of genes with repect to tanshinone biosynthetic pathway obviously. Our results indicated that both of the live C. globosum D38 and its mycelia extracts could be utilized for tanshinones accumulation in S. miltiorrhiza hairy root. What’s more, D38 also could be made into biotic fertilizer applying into S.miltiorrhiza seddlings, which not only promoted host growth but the tanshinones and phenylpropionic acid accumulation. In the soil environment, D38 had formed bitrophic and mutual beneficial relationship with the host and enhanced the primary metabolism on the whole so as to have facilitative effects on phenylpropionic acid accumulation. To sum up, Chaetomium globosum D38 was a highly effective endophytic fungus for S. miltiorrhiza.
