To Gibberellins and Beyond! Insights into the Evolution of Diterpenoid Metabolism

Abstract

The requisite production of gibberellins as hormones necessary for higher plant growth and development has provided a genetic reservoir of biosynthetic genes whose duplication and divergence is thought to underlie the widespread production of more specialized diterpenoids. These natural products occur throughout the plant kingdom, although examples of such metabolism are found more broadly in fungi and bacteria as well, with a total of almost 7,000 such natural products already known. Here I present insights into the evolution of such diterpenoid natural products biosynthesis that arise from our systematic approach to biochemical investigations of such metabolism. In particular, using rice as a model system, we have significantly increased understanding of the underlying biosynthetic processes. This includes identification of all the responsible diterpene synthases and number of the cytochrome P450 mono‐oxygenases. Our investigations have further led to evidence for plasticity in these enzymes and, hence, the corresponding metabolic pathways in not only rice, but the related cereal crop plant wheat, providing insights into the facility with which more specialized metabolism can be derived from gibberellin biosynthesis.