scholarly journals Molecular Basis of the Activation and Dissociation of Dimeric PYL2 Receptor in Abscisic Acid Signaling

2021 ◽  
Author(s):  
Chuankai Zhao ◽  
Diwakar Shukla
Keyword(s):  
Abscisic Acid ◽  
Abiotic Stresses ◽  
Molecular Basis ◽  
Plant Responses ◽  
Biotic And Abiotic Stresses ◽  
Abscisic Acid Signaling ◽  
Aba Receptors

Phytohormone abscisic acid (ABA) is essential for plant responses to biotic and abiotic stresses. Dimeric receptors are a class of ABA receptors that are important for various ABA responses. While...

scholarly journals The Abscisic Acid Pathway Has Multifaceted Effects on the Accumulation of Bamboo mosaic virus

2014 ◽  
Vol 27 (2) ◽  
pp. 177-189 ◽  
Author(s):  
Mazen Alazem ◽  
Kuan-Yu Lin ◽  
Na-Sheng Lin
Keyword(s):  
Abscisic Acid ◽  
Mosaic Virus ◽  
Abiotic Stresses ◽  
Critical Role ◽  
Enzyme Linked Immunosorbent Assay ◽  
Plant Responses ◽  
Virus Induced Gene Silencing ◽  
Biotic And Abiotic Stresses ◽  
Acid Pathway

Accepted 29 October 2013. Abscisic acid (ABA) plays a key role in modulating plant responses to different biotic and abiotic stresses. However, the effect of ABA on virus infection is not fully understood. Here, we describe the effects of the ABA pathway on the accumulation of Bamboo mosaic virus (BaMV) and Cucumber mosaic virus (CMV) in two different hosts: Arabidopsis thaliana and Nicotiana benthamiana. We report that ABA2 plays a critical role in the accumulation of BaMV and CMV. Mutants downstream of ABA2 (aao3, abi1-1, abi3-1, and abi4-1) were susceptible to BaMV, indicating that the ABA pathway downstream of ABA2 is essential for BaMV resistance. The aba2-1 mutant decreased the accumulation of BaMV (+)RNA, (–)RNA, and coat protein, with the most dramatic effect being observed for (–)RNA. These findings were further validated by the use of virus-induced gene silencing and enzyme-linked immunosorbent assay in N. benthamiana. In addition, infecting N. benthamiana with BaMV or CMV increased ABA contents and activated the SA and ABA pathways, thereby disrupting the antagonism between these two cascades. Our findings uncover a novel role for ABA2 in supporting BaMV and CMV accumulation, distinct from the opposing role of its downstream genes.

scholarly journals Infection with an asymptomatic virus in rice results in a delayed drought response

2020 ◽  
Vol 47 (3) ◽  
pp. 239 ◽  
Author(s):  
Jaymee R. Encabo ◽  
Reena Jesusa A. Macalalad-Cabral ◽  
Jerlie Mhay K. Matres ◽  
Sapphire Charlene Thea P. Coronejo ◽  
Gilda B. Jonson ◽  
...  
Keyword(s):  
Drought Stress ◽  
Abiotic Stresses ◽  
Water Status ◽  
Drought Response ◽  
Plant Responses ◽  
Leaf Rolling ◽  
Rice Tungro Spherical Virus ◽  
Biotic And Abiotic Stresses ◽  
Rice Plants ◽  
Increased Susceptibility

Infection of viruses in plants often modifies plant responses to biotic and abiotic stresses. In the present study we examined the effects of Rice tungro spherical virus (RTSV) infection on drought response in rice. RTSV infection delayed the onset of leaf rolling by 1–2 days. During the delay in drought response, plants infected with RTSV showed higher stomatal conductance and less negative leaf water potential under drought than those of uninfected plants, indicating that RTSV-infected leaves were more hydrated. Other growth and physiological traits of plants under drought were not altered by infection with RTSV. An expression analysis of genes for drought response-related transcription factors showed that the expression of OsNAC6 and OsDREB2a was less activated by drought in RTSV-infected plants than in uninfected plants, further suggesting improved water status of the plants due to RTSV infection. RTSV accumulated more in plants under drought than in well-watered plants, indicating the increased susceptibility of rice plants to RTSV infection by drought. Collectively, these results indicated that infection with RTSV can transiently mitigate the influence of drought stress on rice plants by increasing leaf hydration, while drought increased the susceptibility of rice plants to RTSV.

scholarly journals Molecular Basis of the Activation and Dissociation of Dimeric PYL2 Receptor in Abscisic Acid Signaling

2019 ◽  
Author(s):  
Chuankai Zhao ◽  
Diwakar Shukla
Keyword(s):  
Free Energy ◽  
Abscisic Acid ◽  
Critical Role ◽  
Water Molecules ◽  
Plant Responses ◽  
Free Energy Barrier ◽  
Conformational Plasticity ◽  
Dynamics Simulations ◽  
Key Aspects ◽  
Aba Receptors

Phytohormone abscisic acid (ABA) is essential for plant responses to biotic and abiotic stresses. Dimeric receptors are a class of ABA receptors that are important for various ABA responses. While extensive experimental and computational studies have investigated these receptors, it remains not fully understood how ABA leads to their activation and dissociation for interaction with downstream phosphatase. It also remains unknown how networks of water molecules present in the binding site affect ABA perception despite its critical role in protein-ligand binding. Here, we study the activation and the homodimeric association processes of PYL2 receptor as well as its heterodimeric association with the phosphatase HAB1 using molecular dynamics simulations. Free energy landscapes from ~223 μs simulations show that dimerization substantially constrains PYL2 conformational plasticity and stabilizes inactive state, resulting in lower ABA affinity. Using hydration site analysis to characterize receptor solvation thermodynamics, we show that the displacement and reorganization of water molecules upon ABA binding contribute to binding affinity via gain of entropy and enthalpy, respectively. The penalty for expelling water molecules into the bulk causes the free energy barrier to binding (~4-5 kcal/mol). Finally, we establish the thermodynamic model for competitive binding between homodimeric PYL2 association and heterodimeric PYL2-HAB1 association in the absence and presence of ABA. Our results suggest that the binding of ABA destabilizes PYL2 complex and further stabilizes PYL2-HAB1 association, thereby promoting PYL2 dissociation. Overall, this study explains several key aspects on activation of dimeric ABA receptors, which provide new avenues for selective regulation of these receptors.

scholarly journals Initiation and amplification of SnRK2 activation in abscisic acid signaling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhen Lin ◽  
Yuan Li ◽  
Yubei Wang ◽  
Xiaolei Liu ◽  
Liang Ma ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Higher Plants ◽  
Plant Responses ◽  
Activation Loop ◽  
Aba Signaling ◽  
Kinase Activation ◽  
Abscisic Acid Signaling ◽  
Aba Receptor ◽  
Amplification Mechanism

AbstractThe phytohormone abscisic acid (ABA) is crucial for plant responses to environmental challenges. The SNF1-regulated protein kinase 2s (SnRK2s) are key components in ABA-receptor coupled core signaling, and are rapidly phosphorylated and activated by ABA. Recent studies have suggested that Raf-like protein kinases (RAFs) participate in ABA-triggered SnRK2 activation. In vitro kinase assays also suggest the existence of autophosphorylation of SnRK2s. Thus, how SnRK2 kinases are quickly activated during ABA signaling still needs to be clarified. Here, we show that both B2 and B3 RAFs directly phosphorylate SnRK2.6 in the kinase activation loop. This transphosphorylation by RAFs is essential for SnRK2 activation. The activated SnRK2s then intermolecularly trans-phosphorylate other SnRK2s that are not yet activated to amplify the response. High-order Arabidopsis mutants lacking multiple B2 and B3 RAFs show ABA hyposensitivity. Our findings reveal a unique initiation and amplification mechanism of SnRK2 activation in ABA signaling in higher plants.

scholarly journals Phytochrome B regulates reactive oxygen signaling during abiotic and biotic stress in plants

2021 ◽  
Author(s):  
Yosef Fichman ◽  
Haiyan Xiong ◽  
Soham Sengupta ◽  
Rajeev K Azad ◽  
Julian M Hibberd ◽  
...  
Keyword(s):  
Abiotic Stresses ◽  
Light Stress ◽  
Reactive Oxygen ◽  
Plant Responses ◽  
Ros Production ◽  
Phytochrome B ◽  
Biotic And Abiotic Stresses ◽  
Regulatory Module ◽  
Plant Acclimation ◽  
Life On Earth

Plants are essential for life on Earth converting light into chemical energy in the form of sugars. To adjust for changes in light intensity and quality, and to become as efficient as possible in harnessing light, plants utilize multiple light receptors, signaling, and acclimation mechanisms. In addition to altering plant metabolism, development and growth, light cues sensed by some photoreceptors, such as phytochromes, impact on many plant responses to biotic and abiotic stresses. Central for plant responses to different stresses are reactive oxygen species (ROS) that function as key signaling molecules. Recent studies demonstrated that respiratory burst oxidase homolog (RBOH) proteins that reside at the plasma membrane and produce ROS at the apoplast play a key role in plant responses to different biotic and abiotic stresses. Here we reveal that phytochrome B (phyB) and RBOHs function as part of a key regulatory module that controls ROS production, transcript expression, and plant acclimation to excess light stress. We further show that phyB can regulate ROS production during stress even if it is restricted to the cytosol, and that phyB, RBOHD and RBOHF co-regulate thousands of transcripts in response to light stress. Surprisingly, we found that phyB is also required for ROS accumulation in response to heat, wounding, cold, and bacterial infection. Taken together, our findings reveal that phyB plays a canonical role in plant responses to biotic and abiotic stresses, regulating ROS production, and that phyB and RBOHs function in the same pathway.

scholarly journals The single-subunit RING-type E3 ubiquitin ligase RSL1 targets PYL4 and PYR1 ABA receptors in plasma membrane to modulate abscisic acid signaling

2014 ◽  
Vol 80 (6) ◽  
pp. 1057-1071 ◽  
Author(s):  
Eduardo Bueso ◽  
Lesia Rodriguez ◽  
Laura Lorenzo-Orts ◽  
Miguel Gonzalez-Guzman ◽  
Enric Sayas ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Abscisic Acid ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Ring Type ◽  
Abscisic Acid Signaling ◽  
Single Subunit ◽  
Aba Receptors

scholarly journals Members of the abscisic acid co-receptor PP2C protein family mediate salicylic acid-abscisic acid crosstalk

2017 ◽  
Author(s):  
Murli Manohar ◽  
Dekai Wang ◽  
Patricia M. Manosalva ◽  
Hyong Woo Choi ◽  
Erich Kombrink ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Abscisic Acid ◽  
Underlying Mechanism ◽  
Protein Family ◽  
Negative Regulator ◽  
Plant Responses ◽  
Aba Signaling ◽  
Biotic Stresses ◽  
The Face ◽  
Aba Receptors

AbstractThe interplay between abscisic acid (ABA) and salicylic acid (SA) influences plant responses to various (a)biotic stresses; however, the underlying mechanism(s) for this crosstalk is largely unknown. Here we report that type 2C protein phosphatases (PP2Cs), some of which are negative regulators of ABA signaling, bind SA. SA binding suppressed the ABA-enhanced interaction between these PP2Cs and various ABA receptors belonging to the PYR/PYL/RCAR protein family. Additionally, SA suppressed ABA-enhanced degradation of PP2Cs and ABA-induced stabilization of SnRK2s. Supporting SA’s role as a negative regulator of ABA signaling, exogenous SA suppressed ABA-induced gene expression, whereas SA-deficient sid2-1 mutants displayed heightened PP2C degradation and hypersensitivity to ABA-induced suppression of seed germination. Together, these results suggest a new molecular mechanism through which SA antagonizes ABA signaling. A better understanding of the crosstalk between these hormones is important for improving the sustainability of agriculture in the face of climate change.

scholarly journals Function and Mechanism of Jasmonic Acid in Plant Responses to Abiotic and Biotic Stresses

2021 ◽  
Vol 22 (16) ◽  
pp. 8568
Author(s):  
Yun Wang ◽  
Salma Mostafa ◽  
Wen Zeng ◽  
Biao Jin
Keyword(s):  
Jasmonic Acid ◽  
Plant Hormones ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Plant Stress ◽  
Plant Responses ◽  
Biotic And Abiotic Stresses ◽  
Research Attention ◽  
Biotic Stresses ◽  
Plant Stress Responses

As sessile organisms, plants must tolerate various environmental stresses. Plant hormones play vital roles in plant responses to biotic and abiotic stresses. Among these hormones, jasmonic acid (JA) and its precursors and derivatives (jasmonates, JAs) play important roles in the mediation of plant responses and defenses to biotic and abiotic stresses and have received extensive research attention. Although some reviews of JAs are available, this review focuses on JAs in the regulation of plant stress responses, as well as JA synthesis, metabolism, and signaling pathways. We summarize recent progress in clarifying the functions and mechanisms of JAs in plant responses to abiotic stresses (drought, cold, salt, heat, and heavy metal toxicity) and biotic stresses (pathogen, insect, and herbivore). Meanwhile, the crosstalk of JA with various other plant hormones regulates the balance between plant growth and defense. Therefore, we review the crosstalk of JAs with other phytohormones, including auxin, gibberellic acid, salicylic acid, brassinosteroid, ethylene, and abscisic acid. Finally, we discuss current issues and future opportunities in research into JAs in plant stress responses.

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