The Regulatory Domain of SRK2E/OST1/SnRK2.6 Interacts with ABI1 and Integrates Abscisic Acid (ABA) and Osmotic Stress Signals Controlling Stomatal Closure inArabidopsis

The plant hormone abscisic acid (ABA) triggers cellular tolerance responses to osmotic stress caused by drought and salinity. ABA controls the turgor pressure of guard cells in the plant epidermis, leading to stomatal closure to minimize water loss. However, stomatal apertures open to uptake CO2 for photosynthesis even under stress conditions. ABA modulates its signaling pathway via negative feedback regulation to maintain plant homeostasis. In the nuclei of guard cells, the clade A type 2C protein phosphatases (PP2Cs) counteract SnRK2 kinases by physical interaction, and thereby inhibit activation of the transcription factors that mediate ABA-responsive gene expression. Under osmotic stress conditions, PP2Cs bind to soluble ABA receptors to capture ABA and release active SnRK2s. Thus, PP2Cs function as a switch at the center of the ABA signaling network. ABA induces the expression of genes encoding repressors or activators of PP2C gene transcription. These regulators mediate the conversion of PP2C chromatins from a repressive to an active state for gene transcription. The stress-induced chromatin remodeling states of ABA-responsive genes could be memorized and transmitted to plant progeny; i.e., transgenerational epigenetic inheritance. This review focuses on the mechanism by which PP2C gene transcription modulates ABA signaling.

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Implications of Abscisic Acid in the Drought Stress Tolerance of Plants

Agronomy ◽

10.3390/agronomy10091323 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1323 ◽

Cited By ~ 2

Author(s):

Shahid Ali ◽

Kashif Hayat ◽

Amjad Iqbal ◽

Linan Xie

Keyword(s):

Abscisic Acid ◽

Drought Stress ◽

Stress Tolerance ◽

Signaling Pathways ◽

Environmental Changes ◽

Stomatal Closure ◽

Mitigation Strategies ◽

Stress Signals ◽

Post Transcriptional Regulation ◽

Aba Biosynthesis

Drought is a severe environmental constraint, which significantly affects plant growth, productivity, and quality. Plants have developed specific mechanisms that perceive the stress signals and respond to external environmental changes via different mitigation strategies. Abscisic acid (ABA), being one of the phytohormones, serves as an important signaling mediator for plants’ adaptive response to a variety of environmental stresses. ABA triggers many physiological processes, including bud dormancy, seed germination, stomatal closure, and transcriptional and post-transcriptional regulation of stress-responsive gene expression. The site of its biosynthesis and action must be clarified to understand the signaling network of ABA. Various studies have documented multiple sites for ABA biosynthesis, their transporter proteins in the plasma membrane, and several components of ABA-dependent signaling pathways, suggesting that the ABA response to external stresses is a complex networking mechanism. Knowing about stress signals and responses will increase our ability to enhance crop stress tolerance through the use of various advanced techniques. This review will elaborate on the ABA biosynthesis, transportation, and signaling pathways at the molecular level in response to drought stress, which will add a new insight for future studies.

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Faculty Opinions recommendation of Cytoplasmic alkalization precedes reactive oxygen species production during methyl jasmonate- and abscisic acid-induced stomatal closure.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1019111.217426 ◽

2004 ◽

Author(s):

Julian Schroeder

Keyword(s):

Reactive Oxygen Species ◽

Abscisic Acid ◽

Methyl Jasmonate ◽

Reactive Oxygen Species Production ◽

Stomatal Closure ◽

Reactive Oxygen ◽

Oxygen Species ◽

Species Production

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Faculty Opinions recommendation of Stomatal closure by fast abscisic acid signaling is mediated by the guard cell anion channel SLAH3 and the receptor RCAR1.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.10694957.11793055 ◽

2011 ◽

Author(s):

Julian Schroeder

Keyword(s):

Abscisic Acid ◽

Guard Cell ◽

Stomatal Closure ◽

Anion Channel ◽

Abscisic Acid Signaling

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Faculty Opinions recommendation of The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.11003957.11944056 ◽

2011 ◽

Author(s):

Tapio Palva

Keyword(s):

Abscisic Acid ◽

Osmotic Stress ◽

Stress Tolerance ◽

Plant Cuticle ◽

Acid Biosynthesis ◽

Abscisic Acid Biosynthesis ◽

Stress Regulation ◽

Osmotic Stress Tolerance

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Faculty Opinions recommendation of The cytosolic/nuclear HSC70 and HSP90 molecular chaperones are important for stomatal closure and modulate abscisic acid-dependent physiological responses in Arabidopsis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13353024.14724144 ◽

2011 ◽

Author(s):

Daniel Gallie

Keyword(s):

Abscisic Acid ◽

Molecular Chaperones ◽

Physiological Responses ◽

Stomatal Closure

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Inhibition of cambial activity in Abies balsamea by internal water stress: role of abscisic acid

Canadian Journal of Botany ◽

10.1139/b75-333 ◽

1975 ◽

Vol 53 (24) ◽

pp. 3041-3050 ◽

Cited By ~ 35

Author(s):

C. H. A. Little

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Indoleacetic Acid ◽

Stomatal Closure ◽

Abies Balsamea ◽

Cambial Activity ◽

Inhibitory Effect ◽

Internal Water ◽

Endogenous Aba

In experiments with attached and detached shoots of balsam fir, Abies balsamea L., synthetic (±)abscisic acid (ABA) (1) reduced photosynthesis and transpiration by inducing stomatal closure, (2) inhibited indoleacetic acid (IAA) - induced cambial activity in photosynthesizing and non-photosynthesizing shoots, and (3) inhibited the basipetal movement of [14C]IAA. Neither gibberellic acid nor kinetin counteracted the inhibitory effect of (±)ABA on IAA-induced cambial activity. In addition it was demonstrated that increasing the internal water stress increased the level of endogenous ABA in the phloem–cambial region of bark peelings and decreased the basipetal movement of [14C]IAA through branch sections. On the basis of these findings it is proposed that internal water stress inhibits cambial activity, partly through increasing the level of ABA; the ABA acts to decrease the provision of carbohydrates and auxin that are required for cambial growth.

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Arabidopsis NPF4.6 and NPF5.1 Control Leaf Stomatal Aperture by Regulating Abscisic Acid Transport

Genes ◽

10.3390/genes12060885 ◽

2021 ◽

Vol 12 (6) ◽

pp. 885

Author(s):

Takafumi Shimizu ◽

Yuri Kanno ◽

Hiromi Suzuki ◽

Shunsuke Watanabe ◽

Mitsunori Seo

Keyword(s):

Abscisic Acid ◽

Plant Hormone ◽

Leaf Surface ◽

Stomatal Closure ◽

Guard Cells ◽

Cell Types ◽

Acid Transport ◽

Wild Type ◽

Vascular Tissues ◽

Abscisic Acid Transport

The plant hormone abscisic acid (ABA) is actively synthesized in vascular tissues and transported to guard cells to promote stomatal closure. Although several transmembrane ABA transporters have been identified, how the movement of ABA within plants is regulated is not fully understood. In this study, we determined that Arabidopsis NPF4.6, previously identified as an ABA transporter expressed in vascular tissues, is also present in guard cells and positively regulates stomatal closure in leaves. We also found that mutants defective in NPF5.1 had a higher leaf surface temperature compared to the wild type. Additionally, NPF5.1 mediated cellular ABA uptake when expressed in a heterologous yeast system. Promoter activities of NPF5.1 were detected in several leaf cell types. Taken together, these observations indicate that NPF5.1 negatively regulates stomatal closure by regulating the amount of ABA that can be transported from vascular tissues to guard cells.

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