Abstract
We present the engineering of lignan biosynthesis in Forsythia koreana cell suspension cultures for the development of an efficient production method of beneficial lignans. A suspension cell culture prepared from leaves of Forsythia produced lignans, mainly pinoresinol and matairesinol glucosides, at levels comparable to that obtained from the leaves. To increase the pinoresinol content in Forsythia, we generated a transgenic cell line overexpressing an RNA interference (RNAi) construct of a pinoresinol/lariciresinol reductase, PLR (PLR-RNAi). Down-regulation of PLR expression led to a complete loss of matairesinol and an accumulation of approximately 20-fold pinoresinol in its glucoside form in comparison with the non-transformant. Moreover, the Forsythia transgenic cells co-expressing PLR-RNAi and CYP81Q1, which is a cytochrome P450 enzyme responsible for the biosynthesis of sesamin from pinoresinol, exhibited production of sesamin as well as accumulation of pinoresinol glucoside. These data suggest Forsythia cell suspension to be a promising tool for the engineering of lignan production.
