Gibberellin metabolism: new insights revealed by the genes

The identification of most of the genes involved in the metabolic pathways for gibberellin hormones has helped us to understand these pathways and the ir regulation. Many of these enzymes are multifunctional and therefore fewe r enzymes than might be expected are required to synthesize the various gib berellin structures. However, several of the enzymes are encoded by multipl e genes that are regulated differently, adding unexpected genetic complexit y. Several endogenous and environmental factors modify the expression of gi bberellin biosynthesis genes, including developmental stage, hormonal statu s and light. A future challenge will be to dissect the complex, interacting pathways that mediate the regulation of gibberellin metabolism.