The SmMYB36-SmERF6/SmERF115 module regulates the biosynthesis of tanshinones and phenolic acids in salvia miltiorrhiza hairy roots

Abstract

Tanshinone and phenolic acids are the most important active substances of Salvia miltiorrhiza, and the insight into their transcriptional regulatory mechanisms is an essential process to increase their content in vivo. SmMYB36 has been found to have important regulatory functions in the synthesis of tanshinone and phenolic acid, paradoxically, its mechanism of action in S. miltiorrhiza is not clear. Here, we demonstrated that SmMYB36 functions as a promoter of tanshinones accumulation and a suppressor of phenolic acids through the generation of SmMYB36 overexpressed and chimeric SmMYB36-SRDX (EAR repressive domain) repressor hairy roots in combination with transcriptomic-metabolomic analysis. SmMYB36 directly down-regulate the key enzyme gene of primary metabolism, SmGAPC, up-regulate the tanshinones biosynthesis branch genes SmDXS2, SmGGPPS1, SmCPS1 and down-regulate the phenolic acids biosynthesis branch enzyme gene, SmRAS. Meanwhile, SmERF6, a positive regulator of tanshinone synthesis activating SmCPS1, was up-regulated and SmERF115, a positive regulator of phenolic acid biosynthesis activating SmRAS, was down-regulated. Furthermore, the seven acidic amino acids at the C-terminus of SmMYB36 are required for both self-activating domain and activation of target gene expression. As a consequence, this study contributes to reveal the potential relevance of transcription factors synergistically regulating the biosynthesis of tanshinone and phenolic acid.

Comparative transcriptome analysis and identification of candidate R2R3-MYB genes involved in anthraquinone biosynthesis in Rheum palmatum L.

“…Transcription factors have the ability to regulate diverse processes, such as secondary metabolism, by interacting with DNA motifs in the promoter area of genes of interest [ 37 , 55 ]. This regulation is mediated by TFs interaction with itself or with other proteins, depending on its self-transcriptional activity; this activity is analyzed by yeast one-hybrid assays [ 55 ]. In this study, pGBKT7-RpMYB81 and pGBKT7-RpMYB98 were transformed into AH109 to verify whether there was self-activation.…”

The Blinin Accumulation Promoted by CbMYB32 Involved in Conyza blinii Resistance to Nocturnal Low Temperature

“…The phylogenetic tree showed that SmMYB36 was the closest gene to CbMYB32 . SmMYB36 has been demonstrated to interact with enzyme gene promoters or other transcription factors, directly or indirectly regulating the synthesis of tanshinones but inhibiting the synthesis of phenolic acids [ 26 , 27 ]. The phenomenon was discovered that a transcription factor interacting with several pathway genes was also found in other medicinal plants [ 28 ].…”

Transgene‐free CRISPR/Cas9‐mediated gene editing through protoplast‐to‐plant regeneration enhances active compounds in Salvia miltiorrhiza

“…Plants harbouring knockout mutations of either gene had deeper red roots, with higher levels of lipid‐soluble compounds (Figure 1h,i). Overexpressing MYB36 in hairy roots promotes tanshinone accumulation while decreasing phenolic acid levels (Li et al ., 2022). However, MYB36 is primarily expressed in flowers and is homologous to some Arabidopsis MYB genes (Li and Lu, 2014).…”

“…Plants harbouring knockout mutations of either gene had deeper red roots, with higher levels of lipid-soluble compounds (Figure 1h,i). Overexpressing MYB36 in hairy roots promotes tanshinone accumulation while decreasing phenolic acid levels (Li et al, 2022). However, MYB36 is primarily expressed in flowers and is homologous to some Arabidopsis MYB genes (Li and Lu, 2014) More broadly, we demonstrated high-efficiency gene editing of both gene copies of various transcription factor genes regulating the biosynthesis of bioactive compounds in S. miltiorrhiza through a single transfection event using transgene-free CRISPR/Cas9 reagents in protoplasts, and regeneration of knockout plants through a newly established protoplast-toplant regeneration system.…”