Calcium-dependent protein kinase CPK6 positively functions in induction by yeast elicitor of stomatal closure and inhibition by yeast elicitor of light-induced stomatal opening in Arabidopsis.
Yeast elicitor (YEL) induces stomatal closure that is mediated by a Ca(2+)-dependent signaling pathway. A Ca(2+)-dependent protein kinase, CPK6, positively regulates activation of ion channels in abscisic acid and methyl jasmonate signaling, leading to stomatal closure in Arabidopsis (Arabidopsis thaliana). YEL also inhibits light-induced stomatal opening. However, it remains unknown whether CPK6 is involved in induction by YEL of stomatal closure or in inhibition by YEL of light-induced stomatal opening. In this study, we investigated the roles of CPK6 in induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening in Arabidopsis. Disruption of CPK6 gene impaired induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening. Activation by YEL of nonselective Ca(2+)-permeable cation channels was impaired in cpk6-2 guard cells, and transient elevations elicited by YEL in cytosolic-free Ca(2+) concentration were suppressed in cpk6-2 and cpk6-1 guard cells. YEL activated slow anion channels in wild-type guard cells but not in cpk6-2 or cpk6-1 and inhibited inward-rectifying K(+) channels in wild-type guard cells but not in cpk6-2 or cpk6-1. The cpk6-2 and cpk6-1 mutations inhibited YEL-induced hydrogen peroxide accumulation in guard cells and apoplast of rosette leaves but did not affect YEL-induced hydrogen peroxide production in the apoplast of rosette leaves. These results suggest that CPK6 positively functions in induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening in Arabidopsis and is a convergent point of signaling pathways for stomatal closure in response to abiotic and biotic stress.
Graduate School of Environmental and Life Science, Okayama University, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan.
Wenxiu
W
Ye
Daichi
D
Muroyama
Shintaro
S
Munemasa
Yoshimasa
Y
Nakamura
Izumi C
IC
Mori
Yoshiyuki
Y
Murata
D017360:Arabidopsis / Q000201:enzymology / Q000382:microbiology / Q000502:physiology* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D015640:Ion Channel Gating / Q000528:radiation effects; D008027:Light; D009154:Mutation / Q000235:genetics; D054046:Plant Stomata / Q000166:cytology / Q000382:microbiology / Q000502:physiology* / Q000528:radiation effects*; D011523:Protoplasts / Q000378:metabolism / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
D029681:Arabidopsis Proteins; D006861:Hydrogen Peroxide; C516787:CPK6 protein, Arabidopsis; D017871:Calcium-Calmodulin-Dependent Protein Kinases