Flavonols and flavanones are important bioactive compounds with multiple pharmacological activities and health benefits.Transcriptional activation of flavonol and flavanone biosynthesis has been studied extensively,wh...Flavonols and flavanones are important bioactive compounds with multiple pharmacological activities and health benefits.Transcriptional activation of flavonol and flavanone biosynthesis has been studied extensively,while little is known about the negative regulators.CRISPR/Cas9 gene-editing technology,with the advantage of precise genetic modification,is a desirable tool for breeding biofortified materials and exploring potential molecular mechanisms.In this study,a transcriptional repressor,Sl MYB32,was characterized in tomato fruit.Phenotype and metabolomic analyses confirmed that knockout of Sl MYB32 resulted in increased accumulation of flavonols and flavanones,especially about 1 mg g^(-1)FW of quercetin 3-O-rutinoside(rutin).Transcriptome analysis indicated that expression of key genes Sl PAL6,Sl4CL3 and Sl4CL4 as well as five candidate Sl UGTs were significantly up-regulated in slmyb32 mutants.Dual-luciferase and EMSA assays indicated Sl MYB32 could bind to and repress promoter activities of Sl PAL6 and Sl4CL3.Expression of 27 transcription factors belonging to 12 families was significantly changed in slmyb32 mutants,among which two Sl MYBs,two Sl NACs,two Sl AP2s and one Sl WRKY were clustered with known flavonoid regulators.Our results provide new insights into improving bioactive compounds in fruit and understanding negative regulatory mechanisms in flavonol and flavanone biosynthesis.展开更多
基金supported by the National Natural Science Foundation of China(32372667)。
文摘Flavonols and flavanones are important bioactive compounds with multiple pharmacological activities and health benefits.Transcriptional activation of flavonol and flavanone biosynthesis has been studied extensively,while little is known about the negative regulators.CRISPR/Cas9 gene-editing technology,with the advantage of precise genetic modification,is a desirable tool for breeding biofortified materials and exploring potential molecular mechanisms.In this study,a transcriptional repressor,Sl MYB32,was characterized in tomato fruit.Phenotype and metabolomic analyses confirmed that knockout of Sl MYB32 resulted in increased accumulation of flavonols and flavanones,especially about 1 mg g^(-1)FW of quercetin 3-O-rutinoside(rutin).Transcriptome analysis indicated that expression of key genes Sl PAL6,Sl4CL3 and Sl4CL4 as well as five candidate Sl UGTs were significantly up-regulated in slmyb32 mutants.Dual-luciferase and EMSA assays indicated Sl MYB32 could bind to and repress promoter activities of Sl PAL6 and Sl4CL3.Expression of 27 transcription factors belonging to 12 families was significantly changed in slmyb32 mutants,among which two Sl MYBs,two Sl NACs,two Sl AP2s and one Sl WRKY were clustered with known flavonoid regulators.Our results provide new insights into improving bioactive compounds in fruit and understanding negative regulatory mechanisms in flavonol and flavanone biosynthesis.
