Transcriptome sequencing of Salvia miltiorrhiza after infection by its endophytic fungi and identification of genes related to tanshinone biosynthesis

Abstract

Context: Salvia miltiorrhiza Bunge (Labiatae) is a traditional Chinese herb. Endophytic fungi, which are biotic elicitors, can induce accumulation of secondary metabolites in their host plants.

Objective: To analyze the interaction mechanism between S. miltiorrhiza and endophytic fungi.

Materials and methods: Endophytic fungi U104 producing tanshinone IIA were isolated from the healthy disease-free tissue of root of S. miltiorrhiza by conventional methods. The endophytic fungus U104 of S. miltiorrhiza was co-cultured with the sterile seedlings of S. miltiorrhiza for 20 d (temp:day/night = 26 °C/18 °C, photoperiod:12/12 h, illuminance:2000 Lx). Transcriptome sequencing of S. miltiorrhiza seedlings after 20 d of co-cultivation was performed using the Illumina platform.

Results: A total of 3713 differentially expressed genes (DEGs) were obtained. These different expression genes, such as STPII, LTP2, MYB transcription factors, CNGC, CDPK, Rboh, CaM, MAP2K1/MEK1, WRKY33, SGT1/SGT and Hsp90/htpG, showed that host S. miltiorrhiza had biological defence response in the initial stage of interaction. Under the induction of endophytic fungi, 14 key enzyme genes were up-regulated in the tanshinone biosynthesis pathway: DXS, DXS2, DXR, HMGR3, AACT, MK, PMK, GGPPS2, GPPS, KSL, IDI, IPII, FDPS and CPS.

Discussion and conclusions: A total of 14 key genes were obtained from the tanshinone component synthesis and metabolic pathways, providing a reasonable explanation for the accumulation of tanshinone components, an accumulation induced by endophytic fungi, in the host plants. The large amounts of data generated in this study provide a strong and powerful platform for future functional and molecular studies of interactions between host plants and their endophytic fungi.

Keywords:

• Interaction
• metabolic production
• plant stress
• MVA pathway
• MEP pathway
• DEGs

Disclosure statement

The authors declare that they have no competing interests.

Authors’ contributions

The professor Xiying Wei designed the research. Yan Jiang, Lei Wang, Shaorong Lu, Yizhe Xue, Juan Lu and Yanyan Zhang performed the research, contributed to the development of material and PCR and qPCR analysis, then contributed to the writing of the article. All authors read and approved the final manuscript.

Additional information

Funding

We greatly acknowledge the Natural Science Foundation of Shaanxi Province, China (Grant Number 2018JM3018).