Regulation of gibberellin and brassinosteroid biosynthesis by genetic, environmental and hormonal factors

Abstract

The biosynthesis of plant hormones involves a series of steps that converts intermediates with little or no biological activity into the active form. Usually each step is catalysed by an enzyme that is in turn encoded by a gene, referred to as a hormone synthesis gene. Mutations in these genes can give rise to synthesis mutants, which are deficient to varying extents in the hormone in question. The striking phenotypes of some of these mutants provide the most graphic evidence that plant hormones are essential factors for plant growth and development. Striking phenotypes can also be caused by mutations that impair hormone deactivation.