The pyrabactins: Small molecule agonists of the abscisic acid signaling pathway.

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A chemical genetic screen in etiolated Arabidopsis seedlings resulted in the identification of the Pyrabactins (for pyridyl aba activation). Structure-activity analysis revealed the nitrogen in the pyridyl moiety to be important for inhibitory effects of the Pyrabactins on germination and hypocotyl cell expansion. Since many known germination inhibitors affect the GA or ABA pathways, we tested the hypothesis that the Pyrabactins may act through these pathways using mutants. Results suggest that Pyrabactin A activates the ABA signaling. Microarray experiments show that Pyrabactin A is an agonist of the seed-specific ABA pathway. A genetic approach was undertaken to identify mutants resistant to Pyrabactin A. Map-based cloning has been initiated for one of the Pyrabactin A resistant mutants, pyr1. Genetic analysis of pyr1 suggests that resistance is a dominant Mendelian trait. Results from this thesis provide the basis for developing the Pyrabactins as a tool to further delineate the ABA signaling pathway.

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Pagination87 leaves.
Number of Pages87
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Open LibraryOL19551553M
ISBN 109780494211571
OCLC/WorldCa427674202

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Keywords: abscisic acid, PYR/PYL/RCARs, pyrabactin, selectivity, molecular dynamics. Citation: Yang J-F, Yin C-Y, Wang D, Jia C-Y, Hao G-F and Yang G-F () Molecular Determinants Elucidate the Selectivity in Abscisic Acid Receptor and HAB1 Protein Interactions. Front. Chem. doi: /fchemCited by: 1.

The phytohormone abscisic acid (ABA) is the best‐known stress signaling molecule in plants. ABA protects sessile land plants from biotic and abiotic stresses.

Abstract. The plant hormone abscisic acid (ABA) regulates many key processes in plants, including seed germination and development and abiotic stress tolerance, particularly drought resistance. Understanding early events in ABA signal transduction has been a major goal of plant research.

The recent identification of the PYRABACTIN (4-bromo-N- [pyridinyl methyl]naphthalenesulfonamide) RESISTANCE (PYR)/REGULATORY Cited by:   This problem was ingeniously circumvented by a chemical genetics screen by selecting for the ability of mutagenized seeds to germinate in the presence of Pyrabactin, an agonist of ABA (Park et al., ), and independently by yeast two-hybrid screens with the well-studied ABA signaling protein ABSCISIC ACID INSENSITIVE2 (ABI2) as the bait (Ma Cited by: The plant hormone abscisic acid (ABA) regulates many key processes in plants, including seed germination and development and abiotic stress tolerance, particularly drought resistance.

Understanding early events in ABA signal transduction has been a major goal of plant research. Abscisic acid (ABA) biosynthesis, catabolism and signalling have also been a focus for chemical genetics.

ABA plays a central role in germination, seed development and vegetative stress responses. The means to alter ABA homeostasis will help decipher the genetic underpinnings of these processes and generate leads for chemical products that. Abscisic acid (ABA) is one of the “classical” plant hormones, i.e.

discovered at least 50 years ago, that regulates many aspects of plant growth and development. This chapter reviews our current understanding of ABA synthesis, metabolism, transport, and signal transduction, emphasizing knowledge gained from studies of Arabidopsis.

A combination of genetic, molecular and biochemical studies. INTRODUCTION. Abscisic acid (ABA) is an optically active C weak acid that was first identified in the early s as a growth inhibitor accumulating in abscising cotton fruit (“abscisin II”) and leaves of sycamore trees photoperiodically induced to become dormant (“dormin”) (reviewed in Addicott, ).It has since been shown to regulate many aspects of plant growth and development.

activation. The isolation of the selective ABA agonist, pyrabactin, is a notable step toward using synthetic small molecules to control the ABA signaling pathway (Park et al., ).

Of particular interest would be the identification and use of small molecule antagonists and agonists for particular PYR/PYL familymembers. Abscisic acid (ABA) is a plant hormone with important functions in stress protection and physiology.

Recently, the PYR/PYL/RCAR family of intracellular ABA receptors was identified. These receptors directly link ABA perception to a canonical ABA signaling pathway, in which ABA-bound receptors bind and inhibit type 2C phosphatases.

germinate in the presence of Pyrabactin, an agonist of ABA (Park et al., ), and independently by yeast two-hybrid screens with the well-studied ABA signaling protein ABSCISIC ACID INSENSITIVE2 (ABI2) as the bait (Ma et al., ). These two studies had converged to provide the most conclusive evidence to date for a family of 14 small proteins.

Pyrabactin resistance (PYR) 1 and its relatives belong to a family of soluble abscisic acid (ABA) receptors that inhibit type 2C protein phosphatases (PP2C) when in their agonist-stabilized conformation. Given their switch-like properties, we envisioned that mutations that stabilize their agonist-bound conformation could be used to activate signaling in vivo.

Type 2C protein phosphatases (PP2Cs) are vitally involved in abscisic acid (ABA) signaling. Here, we show that a synthetic growth inhibitor called pyrabactin functions as a selective ABA agonist.

Pyrabactin acts through PYRABACTIN RESISTANCE 1 (PYR1), the founding member of a family of START proteins called PYR/PYLs, which are necessary for both pyrabactin and ABA signaling.

Abstract. The phytohormone abscisic acid (ABA) is the best‐known stress signaling molecule in plants. ABA protects sessile land plants from biotic and abiotic stresses. The conserved pyrabactin resistance/pyrabactin resistance‐like/regulatory component of ABA receptors (PYR/PYL/RCAR) perceives ABA and triggers a cascade of signaling events.

Pyrabactin is a synthetic chemical mimicking abscisic acid (ABA), a naturally occurring phytohormone orchestrating abiotic stress responses. ABA and pyrabactin share the same pocket in the ABA receptors but pyrabactin modulates ABA signaling differently, exhibiting both agonistic and antagonistic effects.

The core ABA receptor signalling cascade is comprised of the PYL ABA receptors, PP2Cs and SnRK2s (Figure 1). In the absence of ABA, PP2Cs such as ABI1, ABI2, and HAB1 inhibit the activities of SnRK2s, thus silencing the ABA response.

During abiotic stress. The phytohormone abscisic acid (ABA) plays a crucial role in adaptive responses to environmental stresses, such as drought and high salinity, as well as in plant development, such as seed maturation and dormancy.

PYR/PYL/RCAR has been identified as a bona fide ABA receptor (ABAR) that constitutes the core regulatory component of ABA signaling networks in plants.

Pyrabactin is an efficient agonist for the PYR1 receptor and a weaker agonist for PYL1. In contrast, pyrabactin functions predominantly as antagonist (mixed antagonist/weak agonist) for the PYL2 receptor by adopting a non-productive conformation in the PYL2 ligand–binding pocket.

Increasing drought and diminishing freshwater supplies have stimulated interest in developing small molecules that can be used to control transpiration. Receptors for the plant hormone abscisic acid (ABA) have emerged as key targets for this application, because ABA controls the apertures of stomata, which in turn regulate transpiration.

Here, we describe the rational design of cyanabactin, an. Abscisic acid is a plant hormone with important functions in stress protection and physiology. Recently, the PYR/PYL/RCAR family of intracellular ABA receptors was identified.

These receptors directly link ABA perception to a canonical ABA signaling pathway, in which ABA-bound receptors bind and inhibit type 2C phosphatases.

Pyrabactin is a synthetic ABA agonist that has been used to identify PYR/PYL receptors8. The chemical structure of pyrabactin (Fig. 5a) is not similar to that of (+)ABA (Fig.

2c). ABA activates all PYR/PYL receptors to inhibit PP2C, whereas pyrabactin activates several receptors, such as PYR1 and PYL1, and inhibits others, such as PYL2 8. Small molecules, functioning as agonists or antago-nists of ABA receptors, promote the discovery of ABA receptors and deepen our knowledge of the receptors’ mechanisms of action.

Pyrabactin, the first identi-fied ABA receptor-related small molecule, functions as an agonist of PYR1 and PYL1 and as a weak antag.

acid–perception mutants (fig. S2), which suggests it is an agonist of ABA signaling that inhibits ger-mination in response to environmental stress (17). Aside from ABA analogs, no synthetic agonists of this stress pathway are known. Microarray analyses of the ABA and pyrabactin responses of seeds and seedlings revealed that, in seeds, both.

Fig. Quinabactin activates multiple ABA receptors. (A) Chemical structures of ABA, pyrabactin, and quinabactin.(B) Chemical-dependent inhibition of HAB1 by ABA 50 values (nM) were determined as described in Methods using 50 nM HAB1, nM receptor, and multiple concentrations of compounds; full dose–response curves are provided in Fig.

Melcher K, Ng L-M, Zhou XE, Soon F-F, Xu Y, et al. A gate-latch-lock mechanism for signal transduction by abscisic acid receptors. Nature â 68 Merlot S, Gosti F, Guerrier D, Vavasseur A, Giraudat J. The ABI1 and ABI2 protein phosphatases 2C act in a negative feedback regulatory loop of the abscisic acid signaling pathway.

Functional redundancy widely exists in genes encoding receptors and signaling components of plant hormones, particularly the stress hormone abscisic acid (ABA).

The redundancy hinders the use of conventional genetic approach to dissecting molecular mechanisms for ABA signal. [EN] Receptor-like kinase FERONIA (FER) plays a crucial role in plant response to small molecule hormones [e.g., auxin and abscisic acid (ABA)] and peptide signals [e.g., rapid alkalinization factor (RALF)].

It remains unknown how FER integrates these different signaling events in the control of cell growth and stress responses. Abscisic acid (ABA) is a plant hormone that controls a broad range of processes in plants and is most widely recognized for its involvement in plant adaptation to abiotic stress (Wasilewska et al., ).Drought or salinity lead to an elevation of the ABA stress signal via enhanced ABA biosynthesis, possible ABA release from storage forms, and reduced ABA catabolism in the plant.

The soluble receptors of abscisic acid (ABA) have been identified in Arabidopsis thaliana. The 14 proteins in this family, bearing the double name of PYRABACTIN RESISTANCE/PYRABACTIN-LIKE (PYR/PYL) or REGULATORY COMPONENTS OF ABA RECEPTOR (RCAR) (collectively referred to as PYR/PYL/RCAR), contain between and amino acids with.

We conclude that PYR/PYLs are ABA receptors functioning at the apex of a negative regulatory pathway that controls ABA signaling by inhibiting PP2Cs. Our results illustrate the power of the chemical genetic approach for sidestepping genetic redundancy.

A bscisic acid (ABA), identified in plants in the s, is a small molecule that. Abscisic acid (ABA) is a plant functions in many plant developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure.

It is especially important for plants in the response to environmental stresses, including drought, soil salinity, cold tolerance, freezing tolerance, heat stress and heavy metal ion tolerance. The phytohormone abscisic acid (ABA) regulates plant responses to abiotic stress, such as drought and high osmotic conditions.

The multitude of functionally redundant components involved in ABA signaling poses a major challenge for elucidating individual contributions to the response selectivity and sensitivity of the pathway.

Abscisic Acid: Metabolism, Transport and Signaling Da-Peng Zhang (eds.) This book provides a comprehensive review of all aspects of the molecular and cell biology of abscisic acid (ABA) metabolism, transport and signal transduction, covering our current understanding of. Abscisic Acid Signal Transduction: Function of G Protein–Coupled Receptor 1 in Arabidopsis Nancy A.

Eckardt The Plant Cell Jun16 (6) ; DOI: /tpc Receptor-like kinase FERONIA (FER) plays a crucial role in plant response to small molecule hormones [e.g., auxin and abscisic acid (ABA)] and peptide signals [e.g., rapid alkalinization factor (RALF)].

It remains unknown how FER integrates these different signaling events in the control of cell growth and stress responses. Drought stress is an important environmental factor limiting productivity of plants, especially fast growing species with high water consumption like poplar. Abscisic acid (ABA) is a phytohormone that positively regulates seed dormancy and drought resistance.

The PYR1 (Pyrabactin Resistance 1)/ PYRL (PYR-Like)/ RCAR (Regulatory Component of ABA Receptor) (PYR/PYL/RCAR). abscisic acid-activated signaling pathway: GO Biological Process involved in abscisic acid-activated signaling pathway, positive regulation of response to water deprivation, regulation of protein serine/threonine phosphatase activity: GO Cellular Component located in cytoplasm, cytosol, nucleus: GO Molecular Function.

The chemical structure of pyrabactin, C 16 H 13 BrN 2 O 2 S. This is a hypothetical model of what abscisic acid (ABA) looks like when bound to the receptor protein, PYR1. The yellow molecule is ABA and it is bound inside a pocket of PYR1.

The colored regions in PYR1 (blue red, connected by dashed lines) show parts of PYR1 that are predicted to. Until recently, identified protein targets of the ESCRT machinery in plants mainly corresponded to integral membrane proteins, such as auxin carriers, mineral nutrient transporters, or antigen and hormone receptors (reviewed in Paez Valencia et al., ; Dubeaux and Vert, ; Isono and Kalinowska, ).However, MVB trafficking and vacuolar degradation of soluble proteins have also been.

Abscisic Acid Receptors: Past, Present and FutureF Abscisic Acid Receptors: Past, Present and FutureF Guo, Jianjun; Yang, Xiaohan; Weston, David J.; Chen, Jin‐Gui Introduction Plant hormone abscisic acid (ABA) is an isoprenoid. Both the synthesis and metabolism of ABA are under tight control in response to environmental cues (Nambara and Marion‐Poll ).

This is a hypothetical model of what abscisic acid (ABA) looks like when bound to the receptor protein, PYR1. The yellow molecule is ABA and it is bound inside a pocket of PYR1.are separately exposed to limiting abscisic acid aba is a stress related signaling molecule reported in all human granulocytes 1 2 3 abscisic acid signal transduction jeffrey leung and and jerome giraudat and signaling da peng zhang eds this book provides a comprehensive review of all aspects of the.Receptor-like kinase FERONIA (FER) plays a crucial role in plant response to small molecule hormones [e.g., auxin and abscisic acid (ABA)] and peptide signals [e.g., rapid alkalinization factor (RALF)].

It remains unknown how FER integrates these different signaling events in the control of cell growth and stress responses. Under stress conditions, increased levels of ABA will inhibit cell.

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