New insights into the regulation of stomatal opening by blue light and plasma membrane H(+)-ATPase.

Uptake of CO(2), transpiration, and efflux of O(2) by plants through stomatal pores are indispensable aspects for survival, not only in terrestrial plants but other organisms as well. Stomatal opening is mediated by many environmental and endogenous signals, of which blue light is known to be the most effective signal. Recent investigations have revealed that blue light-induced stomatal opening, mediated by phototropins, is driven by activation of the plasma membrane H(+)-ATPase in guard cells. Moreover, blue light induces activation of H(+)-ATPase via phosphorylation of a penultimate threonine (Thr) in H(+)-ATPase and subsequent binding of the 14-3-3 protein to the phosphorylated H(+)-ATPase. These advances provide novel insights into the blue light-signaling pathway in plants and a regulatory mechanism of the plasma membrane H(+)-ATPase, the first transporter for transport of numerous solutes in plant cells, in response to physiological signals.