Phot Receptors Open the Stomata

Science's STKE  11 Dec 2001:
Vol. 2001, Issue 112, pp. tw453
DOI: 10.1126/stke.2001.112.tw453

Phot1 and phot2 are sensors for the blue light-stimulated responses of phototropism and chloroplast relocation, respectively. Kinoshita et al. provide genetic evidence that phot1 and phot2 function redundantly in sensing blue light for the purpose of increasing stomatal aperture to increase transpiration in response to blue light. Intact Arabidopsis double-mutant plants, but not single-mutant plants, did not increase stomatal aperture in epidermal strips, nor increase transpiration in response to blue light. Furthermore, the defect was in light sensation, based on experiments showing that the downstream H+ ATPase was present and could be activated by the fungal toxin fusicoccin and resulted in stomatal opening and H+ extrusion in wild-type and mutant plants. Thus, phot1 and phot2 now have additional roles in blue light signal transduction as the sensor for stimulating stomatal opening.

T. Kinoshita, M. Doi, N. Suetsugu, T. Kagawa, M. Wada, K.-i. Shimazaki, Phot1 and phot 2 mediate blue light regulation of stomatal opening. Nature 414, 656-660 (2001). [Online Journal]