Uncovering the Role of Hydroxycinnamoyl Transferase in Boosting Chlorogenic Acid Accumulation in Cells under Methyl Jasmonate Elicitation.

Chlorogenic acids (CGAs) are bioactive compounds widely used in the food, pharmaceutical, and cosmetic industries. is an important economic crop, and its suspension cells are rich in CGAs. However, little is known about the biosynthesis and regulation of CGAs in cells. This study first elucidated the regulatory mechanism of CGA biosynthesis in methyl jasmonate (MeJA)-treated cells and the role of the MeJA-responsive () gene in enhancing their CGA accumulation. Firstly, temporal changes in intracellular metabolites showed that MeJA increased the intracellular CGA content up to 1.61-fold to 100.23 mg·g. Meanwhile, 31 primary metabolites showed significant differences, with 6 precursors related to increasing CGA biosynthesis. Secondly, the transcriptome data revealed 3637 new genes previously unannotated in the genome and 3653 differentially expressed genes. The genes involved in the plant signaling pathway and the biosynthesis of CGAs and their precursors showed a general up-regulation, especially the gene family, which ultimately promoted CGA biosynthesis. Thirdly, the expression of a newly annotated and MeJA-responsive gene (, CtNewGene_3476) was demonstrated to be positively correlated with CGA accumulation in the cells, and transient overexpression of enhanced CGA accumulation in tobacco. Finally, in vitro catalysis kinetics and molecular docking simulations revealed the ability and mechanism of the HCT protein to bind to various substrates and catalyze the formation of four hydroxycinnamic esters, including CGAs. These findings strengthened our understanding of the regulatory mechanism of CGA biosynthesis, thereby providing theoretical support for the efficient production of CGAs.