Metabolic engineering of Catharanthus roseus hairy roots for terpenoid indole alkaloid production under light and dark conditions

摘要

The valuable antineoplastic alkaloids vincristine and vinblastine extracted from Catharanthus roseus have seen significant research effort towards increasing their production. Extensive work has shed light on the complex biosynthetic pathways and the strict multilevel regulation that controls metabolite levels and flux. Several enzymes in the later part of the pathway are also light-dependent and may be up- or down-regulated with light exposure. All of this complexity results in a challenging model for plant metabolic engineering. This work characterizes metabolic engineering efforts of the terpenoid indole alkaloid biosynthesis pathway within hairy root cultures of C. roseus at three locations: the indole alkaloid pathway entrance, the non-mevalon-ate/terpenoid alkaloid pathway entrance, and in the terpenoid indole alkaloid (TIA) pathway. The gene overexpression is controlled under a glucocorticoid-inducible promoter system and characterization is performed with metabolite measurements made 72 h after gene induction. The trans-genic lines were also light-adapted to investigate light-mediated regulation of the biosynthesis pathways. Results from this study reveal the levels of regulation in TIA synthesis and will guide further efforts in metabolic engineering.