Histone Deacetylase GiSRT2 Negatively Regulates Flavonoid Biosynthesis in Glycyrrhiza inflata .

Batalin is a medicinal licorice species that has been widely used by humans for centuries. Licochalcone A (LCA) is a characteristic flavonoid that accumulates in roots with high economical value. However, the biosynthetic pathway and regulatory network of its accumulation remain largely unknown. Here we found that a histone deacetylase (HDAC) inhibitor nicotinamide (NIC) could enhance the accumulation of LCA and total flavonoids in seedlings. , a NIC-targeted HDAC was functionally analyzed and its RNAi transgenic hairy roots accumulated much more LCA and total flavonoids than its OE lines and the controls, indicating a negative regulatory role of in the accumulation of LCA and total flavonoids. Co-analysis of transcriptome and metabolome of RNAi- lines revealed potential mechanisms in this process. An -methyltransferase gene, was up-regulated in RNAi- lines and the encoded enzyme catalyzed an intermediate step in LCA biosynthesis pathway. Transgenic hairy roots of proved that is required for LCA accumulation. Together, this work highlights the critical role of in the regulation of flavonoid biosynthesis and identifies as a candidate gene for the biosynthesis of LCA with synthetic biology approaches.