Hiroshi Maeda - Exploiting Evolutionary Diversification of Primary Metabolic Enzymes

Plants synthesize numerous natural products that are critical for plant adaptation and human health. In contrast to well-documented diversification of specialized metabolic enzymes, little is known about the evolution of primary metabolic enzymes that provide precursors to downstream specialized metabolic pathways. Combining evolutionary biochemistry, structure-function, and molecular genetic analyses, we recently uncovered lineage-specific diversification of the biosynthetic pathway of L-tyrosine (Tyr)—an aromatic amino acid required for synthesis of proteins and numerous plant natural products (e.g. vitamin E, dopamine, morphine). Unlike Arabidopsis thaliana having a tightly regulated plastidic Tyr pathway, legumes have an additional cytosolic pathway to synthesize Tyr. Independently, de-regulated Tyr biosynthetic enzymes evolved in the order Caryophyllales (e.g. beet, cactus), which subsequently facilitated the evolution of diverse specialized metabolic pathways derived from Tyr, including betalain pigment biosynthesis. Introduction of these natural enzyme variants or underlying mutations in heterologous plant hosts resulted in elevated accumulation of Tyr. These transgenic lines can now serve as chemical production platforms, on which various Tyr-derived natural product pathways can be reconstructed. I will discuss how primary and specialized metabolic pathways evolved coordinately in a macroevolutionary scale and how primary metabolic diversity can be exploited for rationale plant metabolic engineering and synthetic biology.

Contact Info: maeda2@wisc.edu(link sends e-mail)

Website: https://botany.wisc.edu/staff/maeda-hiroshi-a/