Overexpression of Df4CL1 from Dryopteris fragrans Enhances Flavonoids and Lignin Production in Transgenic Tobacco

Dryopteris fragrans (L.) Schott is a fern in the family Dryopteridaceae that shows a good curative efficacy against several skin diseases, such as psoriasis and athlete’s foot. One of the substances that are effective is a flavonoid. The enzyme 4-Coumaric acid coenzyme A ligase (4CL) plays a key role in the phenylpropanoid metabolism pathway, which controls the metabolic direction of phenylpropanoids and is associated with the synthesis of flavonoids and lignin. In this paper, we examined the role of 4CL1 gene of D. fragrans (Df4CL1) by transferring it to the model plant tobacco. Then its gene function was analyzed through tissue expression, determination of protein and enzyme activity, and assessment of flavonoids and lignin production. The analysis showed that overexpression of Df4CL1 in the transgenic tobacco (TT) had higher protein content, 4CL activity, and content of flavonoids and lignin compared with wild type tobacco (WT). The tissue expression of Df4CL1 in TT was positively correlated with the content of flavonoids and lignin. Therefore, we conclude that Df4CL1 was associated with both flavonoids and lignin biosynthesis by controlling the relative abundance of flavonoids and lignin during normal development.