Transgenic Forsythia plants expressing sesame cytochrome P450 produce beneficial lignans

Abstract

Lignans are widely distributed plant secondary metabolites that have received attention for their benefits to human health. Sesamin is a furofran lignan that is conventionally extracted from Sesamum seeds and shows anti-oxidant and anti-inflammatory activities in the human liver. Sesamin is biosynthesized by the Sesamum-specific enzyme CYP81Q1, and the natural sources of sesamin are annual plants that are at risk from climate change. In contrast, Forsythia species are widely distributed perennial woody plants that highly accumulate the precursor lignan pinoresinol. To sustainably supply sesamin, we developed a transformation method for Forsythia leaf explants and generated transgenic Forsythia plants that heterologously expressed the CYP81Q1 gene. High-performance liquid chromatography (HPLC) and LC-mass spectrometry analyses detected sesamin and its intermediate piperitol in the leaves of two independent transgenic lines of F. intermedia and F. koreana. We also detected the accumulation of sesamin and piperitol in their vegetatively propagated descendants, demonstrating the stable and efficient production of these lignans. These results indicate that CYP81Q1-transgenic Forsythia plants are promising prototypes to produce diverse lignans and provide an important strategy for the cost-effective and scalable production of lignans.

Production of beneficial lignans in heterologous host plants

“…An illustration of the heterologous production of lignans in Forsythia plants: the generation of the transgenic Forsythia plants expressing sesame CYP81Q1 gene results in the production of (+)-sesamin and its intermediate (+)-piperitol ( Figure 1B ) ( Koyama et al., 2022 ). These transgenic Forsythia plants produced (+)-sesamin and (+)-piperitol sustainably, even after repeated vegetative propagation via explants ( Koyama et al., 2022 ). Therefore, the transgenic Forsythia plants serve as prototype heterologous host plants, with the potential for mass propagation as alternative sources of (+)-sesamin and (+)-piperitol.…”