Regulon-guided Discovery of Defensive Secondary Metabolism in Arabidopsis
B. BARCO (1), N. Clay (1) (1) Yale University, U.S.A.

Plant secondary metabolites are crucial in defending plant hosts against microbial pathogens, and secondary metabolite biosynthetic genes represent a significant portion of the plant genome. Arabidopsis thaliana is a model for plant secondary metabolism, with many of its major inducible and constitutively expressed compounds derived from tryptophan (Trp). As most enzymes involved in eukaryotic secondary metabolite biosynthesis are not physically clustered, we previously applied transcriptomics approaches to uncover a novel class of Trp-derived compounds involved in defense. To further increase our efficacy in these methods, we are utilizing an organization common to many secondary metabolic pathways known as the regulon, whereby small numbers of transcription factors activate numerous biosynthetic genes and metabolites. Focusing on two classes of known transcriptional metabolic activators, we discovered that these candidates (1) have wider regulatory functions than were previously known for Trp-derived pathways and (2) that other classes of biosynthetic genes and compounds may also be upregulated. These findings show that regulon-based organization can expand through duplication and neofunctionalization in much the same manner as biosynthetic enzymes. This transcription factor-based approach has the potential to accelerate pathway discovery across stages of development or for other conditions for which there is no known elicitor.

Abstract Number: C12-5, P15-437
Session Type: Concurrent