Flavonols and flavanones are important bioactive compounds with pharmacological activities and health benefits. While transcriptional activation of flavonol and flavanone biosynthesis has been studied extensively, 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.
Against this backdrop, a team of researchers from China identified a transcriptional repressor, SlMYB32, in tomato fruit. They reported their results in the Journal of Integrative Agriculture .
"Phenotype and metabolomic analyses confirmed that knockout of SlMYB32 resulted in increased accumulation of flavonols and flavanones, especially about 1 mg g -1 FW of quercetin 3-O-rutinoside (rutin)," shares corresponding author, Xian Li, a professor at Zhejiang University.
The researchers found through transcriptome analysis that expression of key genes SlPAL6 , Sl4CL3 and Sl4CL4 , as well as five candidate SlUGT s, were significantly up-regulated in slmyb32 mutants. "Dual-luciferase and EMSA assays indicated SlMYB32 could bind to and repress promoter activities of SlPAL6 and Sl4CL3 ," explain Li. "Expression of 27 transcription factors belonging to 12 families was significantly changed in slmyb32 mutants, among which two SlMYBs, two SlNACs, two SlAP2s and one SlWRKY 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," adds Li.
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Contact the author: Ruining Zhang, E-mail: rnzh@zju.edu.cn; #Correspondence Xian Li, E-mail: xianli@zju.edu.cn
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Journal of Integrative Agriculture
Experimental study
Cells
CRISPR/Cas9-mediated mutagenesis of transcriptional repressor SlMYB32 improves flavonols and flavanones accumulation in tomato fruit
The authors declare that they have no conflict of interest.