bHLH transcription factor SmbHLH92 negatively regulates biosynthesis of phenolic acids and tanshinones in Salvia miltiorrhiza

AbstractWater-soluble phenolic acids are major bioactive compounds in the medicinal plant species Salvia miltiorrhiza. Phenolic acid biosynthesis is induced by methyl jasmonate (MeJA) in this important Chinese herb. Here, we investigated the mechanism underlying this induction by analyzing a transcriptome library of S. miltiorrhiza in response to MeJA. Global transcriptome analysis identified the MeJA-responsive R2R3-MYB transcription factor-encoding gene SmMYB1. Overexpressing SmMYB1 significantly promoted phenolic acid accumulation and upregulated the expression of genes encoding key enzymes in the phenolic acid biosynthesis pathway, including cytochrome P450-dependent monooxygenase (CYP98A14). Dual-luciferase (dual-LUC) assays and/or an electrophoretic mobility shift assays (EMSAs) indicated that SmMYB1 activated the expression of CYP98A14, as well as the expression of genes encoding anthocyanin biosynthesis pathway enzymes, including chalcone isomerase (CHI) and anthocyanidin synthase (ANS). In addition, SmMYB1 was shown to interact with SmMYC2 to additively promote CYP98A14 expression compared to the action of SmMYB1 alone. Taken together, these results demonstrate that SmMYB1 is an activator that improves the accumulation of phenolic acids and anthocyanins in S. miltiorrhiza. These findings lay the foundation for in-depth studies of the molecular mechanism underlying MeJA-mediated phenolic acid biosynthesis and for the metabolic engineering of bioactive ingredients in S. miltiorrhiza.

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ABA-responsive transcription factor bZIP1 is involved in modulating biosynthesis of phenolic acids and tanshinones in Salvia miltiorrhiza

Journal of Experimental Botany ◽

10.1093/jxb/eraa295 ◽

2020 ◽

Vol 71 (19) ◽

pp. 5948-5962 ◽

Cited By ~ 2

Author(s):

Changping Deng ◽

Min Shi ◽

Rong Fu ◽

Yi Zhang ◽

Qiang Wang ◽

...

Keyword(s):

Transcription Factor ◽

Phenolic Acids ◽

Phenolic Acid ◽

Leucine Zipper ◽

Salvia Miltiorrhiza ◽

Market Demand ◽

Biosynthetic Genes ◽

Basic Leucine Zipper

Abstract Phenolic acids and tanshinones are major bioactive ingredients in Salvia miltiorrhiza, which possess pharmacological activities with great market demand. However, transcriptional regulation of phenolic acid and tanshinone biosynthesis remains poorly understood. Here, a basic leucine zipper transcription factor (TF) named SmbZIP1 was screened from the abscisic acid (ABA)-induced transcriptome library. Overexpression of SmbZIP1 positively promoted phenolic acid biosynthesis by enhancing expression of biosynthetic genes such as cinnamate-4-hydroxylase (C4H1). Furthermore, biochemical experiments revealed that SmbZIP1 bound the G-Box-like1 element in the promoter of the C4H1 gene. Meanwhile, SmbZIP1 inhibited accumulation of tanshinones mainly by suppressing the expression of biosynthetic genes including geranylgeranyl diphosphate synthase (GGPPS) which was confirmed as a target gene by in vitro and in vivo experiments. In contrast, the phenolic acid content was reduced and tanshinone was enhanced in CRISPR/Cas9 [clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9]-mediated knockout lines. In addition, the previously reported positive regulator of tanshinone biosynthesis, SmERF1L1, was found to be inhibited in SmbZIP1 overexpression lines indicated by RNA sequencing, and was proven to be the target of SmbZIP1. In summary, this work uncovers a novel regulator and deepens our understanding of the transcriptional and regulatory mechanisms of phenolic acid and tanshinone biosynthesis, and also sheds new light on metabolic engineering in S. miltiorrhiza.

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SmMYC2a and SmMYC2b played similar but irreplaceable roles in regulating the biosynthesis of tanshinones and phenolic acids in Salvia miltiorrhiza

Scientific Reports ◽

10.1038/srep22852 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 53

Author(s):

Yangyun Zhou ◽

Wei Sun ◽

Junfeng Chen ◽

Hexin Tan ◽

Ying Xiao ◽

...

Keyword(s):

Transcription Factor ◽

Phenolic Acids ◽

Phenolic Acid ◽

Biosynthetic Pathway ◽

Salvia Miltiorrhiza ◽

Loss Of Function ◽

Bioactive Components ◽

Jaz Proteins ◽

E Box ◽

Inducible Genes

Abstract Salvia miltiorrhiza Bunge, which contains tanshinones and phenolic acids as major classes of bioactive components, is one of the most widely used herbs in traditional Chinese medicine. Production of tanshinones and phenolic acids is enhanced by methyl jasmonate (MeJA). Transcription factor MYC2 is the switch of jasmontes signaling in plants. Here, we focused on two novel JA-inducible genes in S. miltiorrhiza, designated as SmMYC2a and SmMYC2b, which were localized in the nucleus. SmMYC2a and SmMYC2b were also discovered to interact with SmJAZ1 and SmJAZ2, implying that the two MYC2s might function as direct targets of JAZ proteins. Ectopic RNA interference (RNAi)-mediated knockdown experiments suggested that SmMYC2a/b affected multiple genes in tanshinone and phenolic acid biosynthetic pathway. Besides, the accumulation of tanshinones and phenolic acids was impaired by the loss of function in SmMYC2a/b. Meanwhile, SmMYC2a could bind with an E-box motif within SmHCT6 and SmCYP98A14 promoters, while SmMYC2b bound with an E-box motif within SmCYP98A14 promoter, through which the regulation of phenolic acid biosynthetic pathway might achieve. Together, these results suggest that SmMYC2a and SmMYC2b are JAZ-interacting transcription factors that positively regulate the biosynthesis of tanshinones and Sal B with similar but irreplaceable effects.

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Faculty Opinions recommendation of bHLH transcription factor Olig1 is required to repair demyelinated lesions in the CNS.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1023116.264810 ◽

2005 ◽

Author(s):

Magdalena Goetz

Keyword(s):

Transcription Factor ◽

Bhlh Transcription Factor

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Faculty Opinions recommendation of Mutation of a bHLH transcription factor allowed almond domestication.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.735980063.793561372 ◽

2019 ◽

Author(s):

François Parcy

Keyword(s):

Transcription Factor ◽

Bhlh Transcription Factor

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Conserved and non-conserved functions of the rice homologs of the Arabidopsis trichome initiation-regulating MBW complex proteins

BMC Plant Biology ◽

10.1186/s12870-021-03035-0 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Kaijie Zheng ◽

Xutong Wang ◽

Yating Wang ◽

Shucai Wang

Keyword(s):

Transcription Factor ◽

Anthocyanin Biosynthesis ◽

Transcriptional Activator ◽

Myb Transcription Factor ◽

Bhlh Transcription Factor ◽

Seed Color ◽

Transcription Activator ◽

Root Hair Formation ◽

Protoplast Transfection ◽

Mbw Complex

Abstract Background Trichome initiation in Arabidopsis is regulated by a MYB-bHLH-WD40 (MBW) transcriptional activator complex formed by the R2R3 MYB transcription factor GLABRA1 (GL1), MYB23 or MYB82, the bHLH transcription factor GLABRA3 (GL3), ENHANCER OF GLABRA3 (EGL3) or TRANSPARENT TESTA8 (TT8), and the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1). However, the functions of the rice homologs of the MBW complex proteins remained uncharacterized. Results Based on amino acid sequence identity and similarity, and protein interaction prediction, we identified OsGL1s, OsGL3s and OsTTG1s as rice homologs of the MBW complex proteins. By using protoplast transfection, we show that OsGL1D, OsGL1E, OsGL3B and OsTTG1A were predominantly localized in the nucleus, OsGL3B functions as a transcriptional activator and is able to interact with GL1 and TTG1. By using yeast two-hybrid and protoplast transfection assays, we show that OsGL3B is able to interact with OsGL1E and OsTTG1A, and OsGL1E and OsTTG1A are also able to interact with GL3. On the other hand, we found that OsGL1D functions as a transcription activator, and it can interact with GL3 but not OsGL3B. Furthermore, our results show that expression of OsTTG1A in the ttg1 mutant restored the phenotypes including alternations in trichome and root hair formation, seed color, mucilage production and anthocyanin biosynthesis, indicating that OsTTG1A and TTG1 may have similar functions. Conclusion These results suggest that the rice homologs of the Arabidopsis MBW complex proteins are able to form MBW complexes, but may have conserved and non-conserved functions.

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