Phot1 and phot2 mediate blue light-induced transient increases in cytosolic Ca2+ differently in Arabidopsis leaves.

ABSTRACT: Phototropins (phot1 and phot2) are blue light (BL) receptors that mediate phototropism, chloroplast movements, and stomatal opening in Arabidopsis thaliana. Physiological studies have suggested that Ca2+ in the cytoplasm plays a pivotal role in these BL-induced responses. A phot1-mediated increase in cytosolic Ca2+ was reported in deetiolated seedlings of A. thaliana; however, the contribution of phot2 remains unknown. We examined a BL-induced transient increase in cytosolic free Ca2+ in leaves of transgenic A. thaliana of WT plants, phot1 and phot2 mutants, and phot1 phot2 double mutants expressing the Ca2+-sensitive luminescent protein aequorin. phot1 and phot2 had different photosensitivities: phot1 increased cytosolic Ca2+ at lower fluence rates (0.1-50 micromol x m-2 x s-1) and phot2

SUBMITTER: Harada A 

PROVIDER: S-EPMC166272 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature