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Proc Natl Acad Sci U S A. 2015 Jan 13;112(2):613-8. doi: 10.1073/pnas.1423481112. Epub 2014 Dec 30.

Nitric oxide negatively regulates abscisic acid signaling in guard cells by S-nitrosylation of OST1.

Author information

1
Department of Horticulture and Landscape Architecture and.
2
Department of Horticulture and Landscape Architecture and Department of Biology, Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Henan University, Kaifeng 475001, China; and.
3
Department of Horticulture and Landscape Architecture and Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
4
Department of Biochemistry, Purdue University, West Lafayette, IN 47907;
5
Department of Biology, Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Henan University, Kaifeng 475001, China; and.
6
Department of Horticulture and Landscape Architecture and Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China jkzhu@purdue.edu.

Abstract

The phytohormone abscisic acid (ABA) plays important roles in plant development and adaptation to environmental stress. ABA induces the production of nitric oxide (NO) in guard cells, but how NO regulates ABA signaling is not understood. Here, we show that NO negatively regulates ABA signaling in guard cells by inhibiting open stomata 1 (OST1)/sucrose nonfermenting 1 (SNF1)-related protein kinase 2.6 (SnRK2.6) through S-nitrosylation. We found that SnRK2.6 is S-nitrosylated at cysteine 137, a residue adjacent to the kinase catalytic site. Dysfunction in the S-nitrosoglutathione (GSNO) reductase (GSNOR) gene in the gsnor1-3 mutant causes NO overaccumulation in guard cells, constitutive S-nitrosylation of SnRK2.6, and impairment of ABA-induced stomatal closure. Introduction of the Cys137 to Ser mutated SnRK2.6 into the gsnor1-3/ost1-3 double-mutant partially suppressed the effect of gsnor1-3 on ABA-induced stomatal closure. A cysteine residue corresponding to Cys137 of SnRK2.6 is present in several yeast and human protein kinases and can be S-nitrosylated, suggesting that the S-nitrosylation may be an evolutionarily conserved mechanism for protein kinase regulation.

KEYWORDS:

ABA; GSNOR; NO; drought; stomata

PMID:
25550508
PMCID:
PMC4299189
DOI:
10.1073/pnas.1423481112
[Indexed for MEDLINE]
Free PMC Article

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