[Study on tanshinones regulating root-associated microbiomes of Salvia miltiorrhiza]

The plant root-associated microbiomes include root microbiome and rhizosphere microbiome, which are closely related to plant life activities. Nearly 30% of photosynthesis products of plants are used to synthesize root compounds, there is evidence that root compounds regulate and significantly affect the root microbiome Tanshinones are the main hydrophobic components in Salvia miltiorrhiza. In order to study whether these compounds can regulate the root-associated microbiomes of S. miltiorrhiza, our study first identified a white root S. miltiorrhiza(BG) which contains little tanshinones. Retain of the fifth intron of tanshinones synthesis key enzyme gene SmCPS1 leading to the early termination of the SmCPS1 gene, and a stable white root phenotype. Further, wild type(WT) and BG were planted in greenhouse with nutrient soil(Pindstrup, Denmark) and Shandong soil(collected from the S. miltiorrhiza base in Weifang, Shandong), then high-throughput sequencing was used to analyze the root-associated microbiomes. The results showed that the tanshinones significantly affected the root-associated microbiomes of S. miltiorrhiza, and the impact on root microbiomes was more significant. There are significant differences between WT and BG root microbiomes in species richness, dominant strains and co-occurrence network. Tanshinones have a certain repelling effect on Bacilli which belongs to Gram-positive, while specifically attract some Gram-negative bacteria such as Betaproteobacteria and some specific genus of Alphaproteobacteria. This study determined the important role of tanshinones in regulating the structure of root-associated microbiomes from multiple angles, and shed a light for further improving the quality and yield of S. miltiorrhiza through microenvironment regulation.