Difference in abscisic acid perception mechanisms between closure induction and opening inhibition of stomata.
Abscisic acid (ABA) induces stomatal closure and inhibits light-induced stomatal opening. The mechanisms in these two processes are not necessarily the same. It has been postulated that the ABA receptors involved in opening inhibition are different from those involved in closure induction. Here, we provide evidence that four recently identified ABA receptors (PYRABACTIN RESISTANCE1 [PYR1], PYRABACTIN RESISTANCE-LIKE1 [PYL1], PYL2, and PYL4) are not sufficient for opening inhibition in Arabidopsis (Arabidopsis thaliana). ABA-induced stomatal closure was impaired in the pyr1/pyl1/pyl2/pyl4 quadruple ABA receptor mutant. ABA inhibition of the opening of the mutant's stomata remained intact. ABA did not induce either the production of reactive oxygen species and nitric oxide or the alkalization of the cytosol in the quadruple mutant, in accordance with the closure phenotype. Whole cell patch-clamp analysis of inward-rectifying K(+) current in guard cells showed a partial inhibition by ABA, indicating that the ABA sensitivity of the mutant was not fully impaired. ABA substantially inhibited blue light-induced phosphorylation of H(+)-ATPase in guard cells in both the mutant and the wild type. On the other hand, in a knockout mutant of the SNF1-related protein kinase, srk2e, stomatal opening and closure, reactive oxygen species and nitric oxide production, cytosolic alkalization, inward-rectifying K(+) current inactivation, and H(+)-ATPase phosphorylation were not sensitive to ABA.
Graduate School of Natural Science and Technology, Okayama University, Kita-ku, Okayama 700-8530, Japan.
Ye
Y
Yin
Yuji
Y
Adachi
Wenxiu
W
Ye
Maki
M
Hayashi
Yoshimasa
Y
Nakamura
Toshinori
T
Kinoshita
Izumi C
IC
Mori
Yoshiyuki
Y
Murata
D000040:Abscisic Acid / Q000494:pharmacology*; D000468:Alkalies / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D003600:Cytosol / Q000378:metabolism; D015640:Ion Channel Gating / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D009154:Mutation / Q000235:genetics; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D054046:Plant Stomata / Q000166:cytology / Q000187:drug effects* / Q000502:physiology* / Q000528:radiation effects; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011523:Protoplasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
D000468:Alkalies; D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D000040:Abscisic Acid; D006180:Proton-Translocating ATPases