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

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.

2012 ◽  
Author(s):  
David Granot ◽  
Sarah M. Assmann

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.


Author(s):  
Agnieszka Sirko ◽  
Anna Wawrzyńska ◽  
Jerzy Brzywczy ◽  
Marzena Sieńko

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.


2017 ◽  
Author(s):  
Mingxing Tu ◽  
Xianhang Wang ◽  
Yanxun Zhu ◽  
Dejun Wang ◽  
Xuechuan Zhang ◽  
...  

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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tenghua Wang ◽  
Wenxiu Ye ◽  
Yin Wang ◽  
Maoxing Zhang ◽  
Yusuke Aihara ◽  
...  

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.


2016 ◽  
Vol 9 (1) ◽  
pp. 136-147 ◽  
Author(s):  
Marta Peirats-Llobet ◽  
Soon-Ki Han ◽  
Miguel Gonzalez-Guzman ◽  
Cheol Woong Jeong ◽  
Lesia Rodriguez ◽  
...  

2018 ◽  
Vol 115 (42) ◽  
pp. E9971-E9980 ◽  
Author(s):  
Po-Kai Hsu ◽  
Yohei Takahashi ◽  
Shintaro Munemasa ◽  
Ebe Merilo ◽  
Kristiina Laanemets ◽  
...  

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].


2020 ◽  
Vol 21 (24) ◽  
pp. 9517
Author(s):  
Choonkyun Jung ◽  
Nguyen Hoai Nguyen ◽  
Jong-Joo Cheong

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.


2021 ◽  
Vol 22 (9) ◽  
pp. 4638
Author(s):  
Agnieszka Sirko ◽  
Anna Wawrzyńska ◽  
Jerzy Brzywczy ◽  
Marzena Sieńko

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.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Wannarat Pornsiriwong ◽  
Gonzalo M Estavillo ◽  
Kai Xun Chan ◽  
Estee E Tee ◽  
Diep Ganguly ◽  
...  

Organelle-nuclear retrograde signaling regulates gene expression, but its roles in specialized cells and integration with hormonal signaling remain enigmatic. Here we show that the SAL1-PAP (3′-phosphoadenosine 5′- phosphate) retrograde pathway interacts with abscisic acid (ABA) signaling to regulate stomatal closure and seed germination in Arabidopsis. Genetically or exogenously manipulating PAP bypasses the canonical signaling components ABA Insensitive 1 (ABI1) and Open Stomata 1 (OST1); priming an alternative pathway that restores ABA-responsive gene expression, ROS bursts, ion channel function, stomatal closure and drought tolerance in ost1-2. PAP also inhibits wild type and abi1-1 seed germination by enhancing ABA sensitivity. PAP-XRN signaling interacts with ABA, ROS and Ca2+; up-regulating multiple ABA signaling components, including lowly-expressed Calcium Dependent Protein Kinases (CDPKs) capable of activating the anion channel SLAC1. Thus, PAP exhibits many secondary messenger attributes and exemplifies how retrograde signals can have broader roles in hormone signaling, allowing chloroplasts to fine-tune physiological responses.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Yuan ◽  
Jun Meng ◽  
Xiao Liang ◽  
E Yang ◽  
Xu Yang ◽  
...  

Organic molecules of biochar’s leacheates are known to increase the cold resistance of rice seedlings. Yet, it remains unclear whether the organic molecules of biochar leacheates can interact with the abscisic acid (ABA) signaling pathway associated with low temperature. This study used experiments and bioinformatics (molecular docking) to determine which of the organic molecules of biochar’s leacheates could influence the ABA signaling pathway. Specifically, we investigated whether these molecules affected ABA, a plant hormone linked to cold resistance. The contents of endogenous ABA and its precursor carotenoids were determined under low-temperature stress (10°C) and treatment with different concentrations of biochar leacheates. With increased leacheate concentrations, the endogenous ABA and carotenoid contents also increased, as did the expression of ABA- and cold-related genes. When rice seedlings were instead treated with exogenous ABA, it also affected the above-measured indexes; hence, we surmised that certain water-soluble organic molecules of biochar could exert a similar effect as ABA. We first used gas chromatography/mass spectrometry (GC/MS) to identify the organic molecules in the biochar extract, and then we used molecular docking software Autodock to show how they interact. We found that the molecule (1R, 2R, 4S)-2-(6-chloropyridin-3-yl)-7-azabicyclo(2.2.1)heptane was simplified, as Cyah could dock with the ABA receptor protein OsPYL2 in rice, which shows Cyah in biochar is probably an analog of ABA, with a similar function. Based on these results, we conclude that organic molecules of biochar’s leacheates could enter into rice plants and interact with ABA-related proteins to affect the ABA signaling pathway, thereby improving the cold stress resistance of plants.


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