Ion channels in plant signaling

Plant ion channel activities are rapidly modulated in response to several e nvironmental and endogenous stimuli such as light, pathogen attack and phyt ohormones. Electrophysiological as well as pharmacological studies provide strong evidence that ion channels are essential for the induction of specif ic cellular responses, implicating their tight linkage to signal transducti on cascades. Ion channels propagate signals by modulating the membrane pote ntial or by directly affecting cellular ion composition. In addition, they may also be effecters at the end of signaling cascades, as examplified by i on channels which determine the solute content of stomatal guard cells. Pla nt channels are themselves subject to regulation by a variety of cellular f actors, including calcium, pH and cyclic nucleotides. In addition, they app ear to be regulated by (de)-phosphorylation events as well as by direct int eractions with cytoskeletal and other cellular proteins. This review summar izes current knowledge on the role of ion channels in plant signaling.