Chapter One - Towards Complete Elucidation of Monoterpene Indole Alkaloid Biosynthesis Pathway: Catharanthus roseus as a Pioneer System

Abstract

Abstract The development of various plant-based engineering efforts has been facilitated by recent large-scale transcriptomic resources. In consideration of the progress in the study of monoterpene indole alkaloid (MIA) metabolism achieved in the last decade, some strategies have been developed for metabolic engineering efforts. However, unidentified biosynthetic genes in the pathway limit this potential. Catharanthus roseus is the most well-studied medicinal plant owing to its production of valuable anticancer dimeric MIAs such as vinblastine. This chapter highlights the cell-, organ-, development- and environment-specific organisation of MIA biosynthesis and describes the intra- and inter-cellular trafficking of MIAs required for their assembly within C . roseus . The combined use of cell- and organ-specific transcriptome databases of several MIA-accumulating plants is facilitating combined bioinformatic approaches to identify MIA candidate genes. Virus-induced gene silencing is being used to screen candidate genes for their involvement in MIA biosynthesis, and the function of selected genes can be identified by the expression and assay of recombinant proteins in bacterial or yeast systems. These new tools show great promise for a more rapid discovery of new genes involved in whole MIA pathways that enhance the potential of reconstituting them in heterologous microorganisms for the production of any valuable MIA.