Plants can adapt extremely quickly to changes in their environment. Hormones, chemical messengers that are activated in direct response to light and temperature stimuli help them achieve this. Plant steroid hormones similar to human sex hormones play a key role here. Online on August 19, 2014 in Nature Communications, scientists describe a new signaling mode for the brassinosteroid class of hormones. Plants are superior to humans and animals in a number of ways. They have an impressive ability to regenerate, which enables them to regrow entire organs. After being struck by lightning, for example, a tree can grow back its entire crown. But there is one major downside to life as a plant: They are quite literally rooted to the habitats in which they live and therefore completely at the mercy of the elements. In response to this dilemma, plants have developed mechanisms that enable them to rapidly adapt their growth and development to changes. Plant hormones are important enablers of this flexibility. Brassinosteroids play a key role here. These hormones have an effect at the lowest concentrations; they regulate cell elongation and division and are active throughout the entire life cycle of a plant. A team of researchers from Technische Universität München (TUM) and the University of Vienna have now mapped a new signaling mode for brassinosteroids. When brassinosteroids bind to a receptor on a cell wall, they trigger a multi-level cascade of reactions that regulates the activity of the CESTA (CES) transcription factor. Transcription factors bind to the DNA in a cell's nucleus and are capable of activating genes that change the protein composition in the cell.Login Or Register To Read Full Story