scholarly journals Novel regulation of transpiration by sugar signals within guard cells

2012 ◽  
Author(s):  
David Granot ◽  
Sarah M. Assmann
Keyword(s):  
Abscisic Acid ◽  
Signaling Pathway ◽  
Water Loss ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Feedback Mechanism ◽  
Limiting Factor ◽  
Aba Signaling ◽  
Sugar Sensing ◽  
New Discovery

Water is the major limiting factor in agriculture and stomata, composed of two guard cells and the pore they circumscribe, are the chief gates controlling plants’ water loss. The prevailing century old paradigm was that sugars act as an osmoticum in guard cells, contributing to the opening of the stomata. In contrast, we discovered that sugars close stomata and the closure is mediated by the sugar-sensing enzyme hexokinase (HXK) that triggers the abscisic acid (ABA)-signaling pathway within the guard cells. This new discovery suggests a sugar-sensing mechanism within guard cells that controls stomatal closure, and supports the existence of a stomatal feedback mechanism that coordinates photosynthesis with transpiration.

scholarly journals Abscisic acid-independent stomatal CO2 signal transduction pathway and convergence of CO2 and ABA signaling downstream of OST1 kinase

2018 ◽  
Vol 115 (42) ◽  
pp. E9971-E9980 ◽  
Author(s):  
Po-Kai Hsu ◽  
Yohei Takahashi ◽  
Shintaro Munemasa ◽  
Ebe Merilo ◽  
Kristiina Laanemets ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Abscisic Acid ◽  
Protein Kinase ◽  
Stomatal Closure ◽  
Signal Transduction Pathway ◽  
Guard Cells ◽  
Aba Signaling ◽  
Time Resolved ◽  
Aba Receptor ◽  
Biochemical Analyses

Stomatal pore apertures are narrowing globally due to the continuing rise in atmospheric [CO2]. CO2 elevation and the plant hormone abscisic acid (ABA) both induce rapid stomatal closure. However, the underlying signal transduction mechanisms for CO2/ABA interaction remain unclear. Two models have been considered: (i) CO2 elevation enhances ABA concentrations and/or early ABA signaling in guard cells to induce stomatal closure and (ii) CO2 signaling merges with ABA at OST1/SnRK2.6 protein kinase activation. Here we use genetics, ABA-reporter imaging, stomatal conductance, patch clamp, and biochemical analyses to investigate these models. The strong ABA biosynthesis mutants nced3/nced5 and aba2-1 remain responsive to CO2 elevation. Rapid CO2-triggered stomatal closure in PYR/RCAR ABA receptor quadruple and hextuple mutants is not disrupted but delayed. Time-resolved ABA concentration monitoring in guard cells using a FRET-based ABA-reporter, ABAleon2.15, and ABA reporter gene assays suggest that CO2 elevation does not trigger [ABA] increases in guard cells, in contrast to control ABA exposures. Moreover, CO2 activates guard cell S-type anion channels in nced3/nced5 and ABA receptor hextuple mutants. Unexpectedly, in-gel protein kinase assays show that unlike ABA, elevated CO2 does not activate OST1/SnRK2 kinases in guard cells. The present study points to a model in which rapid CO2 signal transduction leading to stomatal closure occurs via an ABA-independent pathway downstream of OST1/SnRK2.6. Basal ABA signaling and OST1/SnRK2 activity are required to facilitate the stomatal response to elevated CO2. These findings provide insights into the interaction between CO2/ABA signal transduction in light of the continuing rise in atmospheric [CO2].

scholarly journals Transcriptional Regulation of Protein Phosphatase 2C Genes to Modulate Abscisic Acid Signaling

2020 ◽  
Vol 21 (24) ◽  
pp. 9517
Author(s):  
Choonkyun Jung ◽  
Nguyen Hoai Nguyen ◽  
Jong-Joo Cheong
Keyword(s):  
Abscisic Acid ◽  
Osmotic Stress ◽  
Gene Transcription ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Stress Conditions ◽  
Physical Interaction ◽  
Aba Signaling ◽  
Negative Feedback Regulation ◽  
Pp2c Gene

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.

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

2014 ◽  
Vol 112 (2) ◽  
pp. 613-618 ◽  
Author(s):  
Pengcheng Wang ◽  
Yanyan Du ◽  
Yueh-Ju Hou ◽  
Yang Zhao ◽  
Chuan-Chih Hsu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Abscisic Acid ◽  
Protein Kinase ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Cysteine Residue ◽  
Aba Signaling ◽  
Related Protein ◽  
Abscisic Acid Signaling ◽  
Evolutionarily Conserved

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.

Phosphonamide pyrabactin analogues as abscisic acid agonists

2015 ◽  
Vol 13 (18) ◽  
pp. 5260-5264 ◽  
Author(s):  
M. Van Overtveldt ◽  
T. S. A. Heugebaert ◽  
I. Verstraeten ◽  
D. Geelen ◽  
C. V. Stevens
Keyword(s):  
Abscisic Acid ◽  
Signaling Pathway ◽  
Stomatal Closure ◽  
Aba Signaling ◽  
Germination Assay

A 4-step synthesis towards phosphonic pyrabactin analogues is presented. Via a stomatal closure and germination assay, their ability to selectively induce the ABA-signaling pathway was demonstrated.

scholarly journals Under salt stress guard cells rewire ion transport and abscisic acid (ABA) signaling

2021 ◽  
Author(s):  
Sohail M. Karimi ◽  
Matthias Freund ◽  
Brittney M. Wager ◽  
Michael Knoblauch ◽  
Jörg Fromm ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Salt Stress ◽  
Ion Transport ◽  
Guard Cells ◽  
Aba Signaling

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

Genes ◽  
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.

scholarly journals Control of ABA Signaling and Crosstalk With Other Hormones by Selective Degradation of Pathway Components

2021 ◽  
Author(s):  
Agnieszka Sirko ◽  
Anna Wawrzyńska ◽  
Jerzy Brzywczy ◽  
Marzena Sieńko
Keyword(s):  
Abscisic Acid ◽  
Signaling Pathway ◽  
Plant Hormone ◽  
Aba Signaling ◽  
Degradation Mechanisms ◽  
E3 Ligases ◽  
Selective Autophagy ◽  
Selective Degradation ◽  
Different Parts

A rapid and appropriate genetic and metabolic acclimation, which is crucial for plants’ survival in a changing environment, is maintained due to the coordinated action of plant hormones and cellular degradation mechanisms influencing proteostasis. The plant hormone abscisic acid (ABA) rapidly accumulates in plants in response to environmental stress and plays a pivotal role in the reaction to various stimuli. Increasing evidence demonstrates a significant role of autophagy in controlling ABA signaling. This field has been extensively investigated and new discoveries are constantly being provided. We present updated information on the components of the ABA signaling pathway, particularly on transcription factors modified by different E3 ligases. Then, we focus on the role of selective autophagy in ABA pathway control and review novel evidence on the involvement of autophagy in different parts of the ABA signaling pathway that are important for crosstalk with other hormones, particularly cytokinins and brassinosteroids.

scholarly journals VlbZIP30 of grapevine functions in drought tolerance via the abscisic acid core signaling pathway

2017 ◽  
Author(s):  
Mingxing Tu ◽  
Xianhang Wang ◽  
Yanxun Zhu ◽  
Dejun Wang ◽  
Xuechuan Zhang ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Signaling Pathway ◽  
Growth And Development ◽  
Transgenic Arabidopsis ◽  
Dehydration Stress ◽  
Aba Signaling ◽  
Group A ◽  
Cotyledon Greening

AbstractDrought stress limits the growth and development of grapevines, thereby reducing productivity, but the mechanisms by which grapevines respond to drought stress remain largely uncharacterized. Here, we characterized a group A bZIP gene from ‘Kyoho’ grapevine, VlbZIP30, which was shown to be induced by abscisic acid (ABA) and dehydration stress. Overexpression of VlbZIP30 in transgenic Arabidopsis enhanced dehydration tolerance during seed germination, and in the seedling and adult stages. Transcriptome analysis revealed that a major proportion of ABA- and/or drought-responsive genes are transcriptionally regulated by VlbZIP30 during ABA or mannitol treatment at the cotyledon greening stage. We identified an A. thaliana G-box motif (CACGTG) and a potential grapevine G-box motif (MCACGTGK) in the promoters of the 39 selected A. thaliana genes up-regulated in the transgenic plants and in the 35 grapevine homologs, respectively. Subsequently, using two grapevine-related databases, we found that 74% and 84% (a total of 27 genes) of the detected grapevine genes were significantly up-regulated by ABA and drought stress, respectively, suggesting that these 27 genes involve in ABA or dehydration stress and may be regulated by VlbZIP30 in grapevine. We propose that VlbZIP30 functions as a positive regulator of drought-responsive signaling in the ABA core signaling pathway.HighlightVlbZIP30 positively regulate plant drought tolerance through regulated the expression of 27 grapevine candidate genes via G-box cis-element (MCACGTGK) in ABA signaling pathway.

scholarly journals Protease Inhibitor-Dependent Inhibition of Light-Induced Stomatal Opening

2021 ◽  
Vol 12 ◽  
Author(s):  
Tenghua Wang ◽  
Wenxiu Ye ◽  
Yin Wang ◽  
Maoxing Zhang ◽  
Yusuke Aihara ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Protease Inhibitor ◽  
Signaling Pathway ◽  
Stomatal Closure ◽  
Screening Method ◽  
Stomatal Opening ◽  
Matrix Metalloproteinase 2 ◽  
Aba Signaling ◽  
Bioinformatics Analyses ◽  
Chemical Screening

Stomata in the epidermis of plants play essential roles in the regulation of photosynthesis and transpiration. Stomata open in response to blue light (BL) by phosphorylation-dependent activation of the plasma membrane (PM) H+-ATPase in guard cells. Under water stress, the plant hormone abscisic acid (ABA) promotes stomatal closure via the ABA-signaling pathway to reduce water loss. We established a chemical screening method to identify compounds that affect stomatal movements in Commelina benghalensis. We performed chemical screening using a protease inhibitor (PI) library of 130 inhibitors to identify inhibitors of stomatal movement. We discovered 17 PIs that inhibited light-induced stomatal opening by more than 50%. Further analysis of the top three inhibitors (PI1, PI2, and PI3; inhibitors of ubiquitin-specific protease 1, membrane type-1 matrix metalloproteinase, and matrix metalloproteinase-2, respectively) revealed that these inhibitors suppressed BL-induced phosphorylation of the PM H+-ATPase but had no effect on the activity of phototropins or ABA-dependent responses. The results suggest that these PIs suppress BL-induced stomatal opening at least in part by inhibiting PM H+-ATPase activity but not the ABA-signaling pathway. The targets of PI1, PI2, and PI3 were predicted by bioinformatics analyses, which provided insight into factors involved in BL-induced stomatal opening.

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