The brassinosteroid signaling network-a paradigm of signal integration.

Many hormonal and environmental signals regulate common cellular and developmental processes in plants. While the molecular pathways that transduce these signals have each been studied in detail, how these pathways are wired into regulatory networks to provide the coordinated responses has remained an outstanding question. Recent studies of the brassinosteroid signaling network have revealed extensive signal integration through direct interactions between components of different signaling pathways. In particular, a circuit of interacting transcription regulators integrates many signaling pathways to enable coordinated and coherent regulation of seedling morphogenesis by hormonal and environmental signals. The recent studies support an emerging theme that complex networks of highly integrated signaling pathways underlie the high levels of developmental plasticity and environmental adaptability of plants.