2021 article

Molecular and Biochemical Characterization of Two 4-Coumarate: Coa Ligase Genes in Tea Plant (Camellia Sinensis)

Li, M., Guo, L., Wang, Y., Li, Y., Jiang, X., Liu, Y., … Xia, T. (2021, September 21).

By: M. Li n, L. Guo*, Y. Wang*, Y. Li*, X. Jiang*, Y. Liu*, D. Xie n, L. Gao*, T. Xia*

Source: ORCID
Added: September 22, 2021

Abstract Tea is rich in flavonoids benefiting human health. Lignin is essential for tea plant growth. Both flavonoids and lignin defend plants from stresses. The biosynthesis of lignin and flavonoids shares a key intermediate, p-coumaroyl-CoA, which is formed from p-coumaric acid catalyzed by p-coumaric acid: CoA ligase (4CL). Herein, we reported two 4CL paralogs from tea plant, Cs4CL1 and Cs4CL2 , which were a member of class I and II, respectively. Cs4CL1 was mainly expressed in roots and stems, while Cs4CL2 was mainly expressed in leaves. The promoter of Cs4CL1 had AC, light and stress-inducible (LSI), and meristem-specific elements, while that of Cs4CL2 had AC and LSI elements only. Moreover, the promoter of Cs4CL1 had two more stress-inducible elements than Cs4CL2 had and the two promoters had six different light-inducible elements. These features suggested their differences in their responses to environmental conditions. Three stress treatments indicated that the expression of Cs4CL1 was sensitive to mechanical wounding, while the expression of Cs4CL2 was UV-B-inducible. Enzymatic assay showed that both recombinant Cs4CL1 and Cs4CL2 transformed p-coumaric acid, ferulic acid and caffeic acid to their corresponding CoA ethers. Kinetic analysis indicated that the recombinant Cs4CL1 preferred to catalyze caffeic acid, while the recombinant Cs4CL2 favored to catalyze p-coumaric acid. The overexpression of both Cs4CL1 and Cs4CL2 increased the levels of chlorogenic acid and total lignin in transgenic tobacco seedlings. In addition, the overexpression of Cs4CL2 increased the levels of three flavonoid compounds. These findings indicate the differences of Cs4CL1 and Cs4CL2 in the phenylpropanoid metabolism.