Polyphenols are the main active components of the anti-inflammatory compounds in dandelion,and chlorogenic acid(CGA)is one of the primary polyphenols.However,the molecular mechanism underlying the transcriptional regu...Polyphenols are the main active components of the anti-inflammatory compounds in dandelion,and chlorogenic acid(CGA)is one of the primary polyphenols.However,the molecular mechanism underlying the transcriptional regulation of CGA biosynthesis remains unclear.Hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase(HQT2)is the last rate-limiting enzyme in chlorogenic acid biosynthesis in Taraxacum antungense.Therefore,using the TaHQT2 gene promoter as a probe,a yeast one-hybrid library was performed,and a basic helix-loop-helix(bHLH)transcription factor,TabHLH1,was identified that shared substantial homology with Gynura bicolor DC bHLH1.The TabHLH1 transcript was highly induced by salt stress,and the TabHLH1 protein was localized in the nucleus.CGA and luteolin concentrations in TabHLH1-overexpression transgenic lines were significantly higher than those in the wild type,while CGA and luteolin concentrations in TabHLH1-RNA interference(RNAi)transgenic lines were significantly lower.Quantitative real-time polymerase chain reaction demonstrated that overexpression and RNAi of TabHLH1 in T.antungense significantly affected CGA and luteolin concentrations by upregulating or downregulating CGA and luteolin biosynthesis pathway genes,especially TaHQT2,4-coumarate-CoA ligase(Ta4CL),chalcone isomerase(TaCHI),and flavonoid-3′-hydroxylase(TaF3′H).Dual-luciferase,yeast one-hybrid,and electrophoretic mobility shift assays indicated that TabHLH1 directly bound to the bHLH-binding motifs of proTaHQT2 and proTa4CL.This study suggests that TabHLH1 participates in the regulatory network of CGA and luteolin biosynthesis in T.antungense and might be useful for metabolic engineering to promote plant polyphenol biosynthesis.展开更多
基金This work was supported by the Zhejiang Provincial Ten Thousand Program for Leading Talents of Science and Technology Innovation[2018R52050]the National Natural Science Fund of China[Grant numbers:82073963,81522049,81703636,31571735,31270007]+1 种基金the Zhejiang Provincial Program for the Cultivation of High-Level Innovative Health Talents,the Research Project of Zhejiang Chinese Medical University(2021JKZDZC06)the Opening Project of Zhejiang Provincial Preponderant and Characteristic Subject of Key University(Traditional Chinese Pharmacology),Zhejiang Chinese Medical University[ZYAOXZD2019006]。
文摘Polyphenols are the main active components of the anti-inflammatory compounds in dandelion,and chlorogenic acid(CGA)is one of the primary polyphenols.However,the molecular mechanism underlying the transcriptional regulation of CGA biosynthesis remains unclear.Hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase(HQT2)is the last rate-limiting enzyme in chlorogenic acid biosynthesis in Taraxacum antungense.Therefore,using the TaHQT2 gene promoter as a probe,a yeast one-hybrid library was performed,and a basic helix-loop-helix(bHLH)transcription factor,TabHLH1,was identified that shared substantial homology with Gynura bicolor DC bHLH1.The TabHLH1 transcript was highly induced by salt stress,and the TabHLH1 protein was localized in the nucleus.CGA and luteolin concentrations in TabHLH1-overexpression transgenic lines were significantly higher than those in the wild type,while CGA and luteolin concentrations in TabHLH1-RNA interference(RNAi)transgenic lines were significantly lower.Quantitative real-time polymerase chain reaction demonstrated that overexpression and RNAi of TabHLH1 in T.antungense significantly affected CGA and luteolin concentrations by upregulating or downregulating CGA and luteolin biosynthesis pathway genes,especially TaHQT2,4-coumarate-CoA ligase(Ta4CL),chalcone isomerase(TaCHI),and flavonoid-3′-hydroxylase(TaF3′H).Dual-luciferase,yeast one-hybrid,and electrophoretic mobility shift assays indicated that TabHLH1 directly bound to the bHLH-binding motifs of proTaHQT2 and proTa4CL.This study suggests that TabHLH1 participates in the regulatory network of CGA and luteolin biosynthesis in T.antungense and might be useful for metabolic engineering to promote plant polyphenol biosynthesis.
