ABSTRACT
Optimal growth and differentiation of plants require coordinated regulation of cellular and intercellular processes and their continuous adaptation to the variable environment. Efficient mechanisms evolved during plant evolution for sensing the environment, for translation of these data into biological information, for transfer of this information within the organism, and for initiation of appropriate reactions. These processes of biological signal transduction comprise the perception of endogenous and environmental signals, the generation of endogenous cellular and systemic signals, and their transmission to the appropriate response targets. Receptor proteins of the plasma membrane or the cytoplasm specifically bind and thereby recognize the signals and either alone or in concert with other proteins initiate cellular signaling processes. Intracellular mediators form the basis of complex cellular signaling networks that are responsible for signal transmission, integration, and evaluation and response activation. Although plants lack an equivalent of the circulating bloodstream, the responses can include the production and secretion of systemic signals that are transported throughout the plant and are recognized by receptors of target cells.
