Recent discovery of PYR/PYL/RCAR-type abscisic acid （ABA） receptors has become one of most significant advances in plant science in the past decade. In mammals, endosomal sorting acts as an important pathway to down...Recent discovery of PYR/PYL/RCAR-type abscisic acid （ABA） receptors has become one of most significant advances in plant science in the past decade. In mammals, endosomal sorting acts as an important pathway to downregulate different types of receptors, but its role in plant hormone signaling is poorly understood. Here, we report that an ubiquitin E2-1ike protein, VPS23A, which is a key component of ESCRT-I, negatively regulates ABA signaling. VPS23A has epistatic relationship with PYR/PYL/RCAR-type ABA receptors and disruption of VPS23A enhanced the activity of key kinase OST1 in the ABA signaling pathway under ABA treatment. Moreover, VPS23A interacts with PYR1/PYLs and K63-1inked diubiquitin, and PYL4 possesses K63-1inked ubiquitinated modification in vivo. Further analysis revealed that VPS23A affects the subcellular localization of PYR 1 and the stability of PYL4. Taken together, our results suggest that VPS23A affects PYR1/ PYL4 via vacuole-mediated degradation, providing an advanced understanding of both the turnover of ABA receptors and ESCRTs in plant hormone signaling.展开更多
盐胁迫是常见的非生物胁迫因素之一并严重地影响着植物的生长发育。简述了植物在应对盐胁迫时,在胁迫信号的感知、信号的转导和传递、胁迫诱导基因的表达等方面所形成的一系列适应性的分子机制,回顾了近年来对脱落酸信号转导和其受体的...盐胁迫是常见的非生物胁迫因素之一并严重地影响着植物的生长发育。简述了植物在应对盐胁迫时,在胁迫信号的感知、信号的转导和传递、胁迫诱导基因的表达等方面所形成的一系列适应性的分子机制,回顾了近年来对脱落酸信号转导和其受体的研究。分析表明脱落酸受体PYR/PYL/RCAR(pyrabatin resistance/like-pyrabatin resistance/regularly component of ABA receptors)的发现使得ABA的信号转导通路更为清楚,使ABA与植物耐盐胁迫的关系更加明确,认为ABA在植物耐盐信号转导途径中发挥了重要的作用,与经济作物的耐盐性密切相关。展开更多
植物激素脱落酸(ABA)参与从种子萌发到植物开花、结果和衰老等多个生长发育过程。研究ABA细胞信号转导的分子机制对进一步阐明其功能具有重要的意义。通过介绍FCA(Flowering Control Locus A)、Mg离子螯合酶H亚基(ABAR/CHLH)、G蛋白偶...植物激素脱落酸(ABA)参与从种子萌发到植物开花、结果和衰老等多个生长发育过程。研究ABA细胞信号转导的分子机制对进一步阐明其功能具有重要的意义。通过介绍FCA(Flowering Control Locus A)、Mg离子螯合酶H亚基(ABAR/CHLH)、G蛋白偶联受体(GCR2)、GTG1/GTG2(GPCR-type G-Proteins1/2)和PYR1/PYL/RCAR在ABA信号传导途径中的作用模式,阐述了其能够接受ABA信号并激活相关下游组分,从而完成其生理功能。展开更多
为了了解小麦ABA受体基因TaPYL9(Pyrabactin resistance like 9)在非生物胁迫下的功能,通过同源克隆法获得小麦TaPYL9基因,对其进行生物信息学分析,并采用实时荧光定量PCR(qRT-PCR)技术检测该基因在ABA、NaCl和PEG处理下的表达情况。结...为了了解小麦ABA受体基因TaPYL9(Pyrabactin resistance like 9)在非生物胁迫下的功能,通过同源克隆法获得小麦TaPYL9基因,对其进行生物信息学分析,并采用实时荧光定量PCR(qRT-PCR)技术检测该基因在ABA、NaCl和PEG处理下的表达情况。结果表明,TaPYL9 cDNA全长1173 bp,开放阅读框618 bp,编码1个包含205个氨基酸残基的不稳定的亲水蛋白,该蛋白以α-螺旋为主,含有1个由2个α-螺旋和7个β-折叠组成的PYL螺旋手柄结构;TaPYL9蛋白与山羊草AsPYL9-like蛋白亲缘关系最近,与拟南芥AtPYL9蛋白属于同一亚族;TaPYL9蛋白和AsPYL9-like蛋白保守基序相同,与拟南芥13个PYL中的AtPYL9蛋白的保守基序相似性最高;TaPYL9在ABA、NaCl和PEG处理下总体上表达量上升。综上,TaPYL9为小麦ABA受体蛋白,对ABA敏感,可能参与小麦高盐和干旱胁迫应答的调控。展开更多
Plant hormone abscisic acid （ABA） serves as an integrator of environmental stresses such as drought to trig-ger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1,...Plant hormone abscisic acid （ABA） serves as an integrator of environmental stresses such as drought to trig-ger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1, an outward anion channel required for stomatal closure, was regulated via reversible protein phosphorylation events involving ABA signaling components, including protein phosphatase 2C members and a SnRK2-type kinase （OST1）. In this study, we reconstituted the ABA signaling pathway as a protein-protein interaction relay from the PYL/RCAR-type receptors, to the PP2C-SnRK2 phosphatase-kinase pairs, to the ion channel SLAC1. The ABA receptors interacted with and inhibited PP2C phosphatase activity against the SnRK2-type kinase, releasing active SnRK2 kinase to phosphorylate, and activate the SLAC1 channel, leading to reduced guard cell turgor and stomatal closure. Both yeast two-hybrid and bimolecular fluorescence complementation assays were used to verify the interactions among the components in the pathway. These biochemical assays demonstrated activity modifications of phosphatases and kinases by their interaction partners. The SLAC1 channel activity was used as an endpoint readout for the strength of the signaling pathway, depending on the presence of different combinations of signaling components. Further study using transgenic plants overexpressing one of the ABA receptors demonstrated that changing the relative level of interacting partners would change ABA sensitivity.展开更多
Abscisic acid （ABA） is a major phytohormone involved in important stress-related and developmental plant processes. Membrane-delimited ABA signal transduction plays an important role in early ABA signaling, but the ...Abscisic acid （ABA） is a major phytohormone involved in important stress-related and developmental plant processes. Membrane-delimited ABA signal transduction plays an important role in early ABA signaling, but the molecular mechanisms connecting core signaling components to the plasma membrane remain un- clear. Plants have evolved a large number of receptor-like kinases （RLKs） to modulate diverse biological processes by perceiving extracellular stimuli and activating downstream signaling responses. In this study, a putative leucine-rich repeat-RLK gene named RECEPTOR DEAD KINASE1 （AtRDK1） was identified and characterized in Arabidopsis thaliana. RDK1 promoter-GUS analysis revealed that RDK1 is expressed ubiq- uitously in the various tissues in Arabidopsis, and its expression is mainly induced by ABA. In the presence of ABA, RDKl-deficient rdkl-1 and rdkl-2 lines showed significant resistance in cotyledon greening and root growth, whereas RDKl-overexpressing lines showed enhanced sensitivity. Consistently, the expres- sion of ABA-responsive genes was significantly downregulated in rdkl mutant seedlings, which were also hypersensitive to drought stress with increased water loss. Interestingly, RDK1 was found to be an atypical kinase localized to the plasma membrane and did not require its kinase activity during ABA-mediated inhi- bition of seedling development. Accordingly, RDK1 interacted in the plasma membrane with type 2C protein phosphatase ABSClSIC ACID INSENSITIVE1 （ABI1）; this interaction was further enhanced by exogenous application of ABA, suggesting that RDKl-mediated recruitment of ABI1 onto the plasma membrane is important for ABA signaling. Taken together, these results reveal an important role for RDK1 in plant responses to abiotic stress conditions in an ABA-dependent manner.展开更多
ABA是调控植物体生长发育和响应外界应激的重要植物激素之一。近年来, ABA受体的筛选和鉴定取得了突破性进展, 为植物中ABA信号转导通路的阐明奠定了重要基础。该文主要综述了ABA-binding protein/H subunit of Mg-chelatase (ABAR/CHLH...ABA是调控植物体生长发育和响应外界应激的重要植物激素之一。近年来, ABA受体的筛选和鉴定取得了突破性进展, 为植物中ABA信号转导通路的阐明奠定了重要基础。该文主要综述了ABA-binding protein/H subunit of Mg-chelatase (ABAR/CHLH)、G protein-coupled receptor 2 (GCR2)、GPCR-type G protein 1/2 (GTG1/2)和pyrabactin resistant/PYR-like/regulatory component of ABA (PYR/PYL/RCAR)被报道为ABA受体的研究历程, 重点介绍了以ABAR/CHLH和PYR/PYL/RCAR为受体的ABA信号转导通路模型的构建, 旨在为ABA受体及其信号转导通路的相关研究提供参考。展开更多
文摘Recent discovery of PYR/PYL/RCAR-type abscisic acid （ABA） receptors has become one of most significant advances in plant science in the past decade. In mammals, endosomal sorting acts as an important pathway to downregulate different types of receptors, but its role in plant hormone signaling is poorly understood. Here, we report that an ubiquitin E2-1ike protein, VPS23A, which is a key component of ESCRT-I, negatively regulates ABA signaling. VPS23A has epistatic relationship with PYR/PYL/RCAR-type ABA receptors and disruption of VPS23A enhanced the activity of key kinase OST1 in the ABA signaling pathway under ABA treatment. Moreover, VPS23A interacts with PYR1/PYLs and K63-1inked diubiquitin, and PYL4 possesses K63-1inked ubiquitinated modification in vivo. Further analysis revealed that VPS23A affects the subcellular localization of PYR 1 and the stability of PYL4. Taken together, our results suggest that VPS23A affects PYR1/ PYL4 via vacuole-mediated degradation, providing an advanced understanding of both the turnover of ABA receptors and ESCRTs in plant hormone signaling.
文摘盐胁迫是常见的非生物胁迫因素之一并严重地影响着植物的生长发育。简述了植物在应对盐胁迫时,在胁迫信号的感知、信号的转导和传递、胁迫诱导基因的表达等方面所形成的一系列适应性的分子机制,回顾了近年来对脱落酸信号转导和其受体的研究。分析表明脱落酸受体PYR/PYL/RCAR(pyrabatin resistance/like-pyrabatin resistance/regularly component of ABA receptors)的发现使得ABA的信号转导通路更为清楚,使ABA与植物耐盐胁迫的关系更加明确,认为ABA在植物耐盐信号转导途径中发挥了重要的作用,与经济作物的耐盐性密切相关。
文摘植物激素脱落酸(ABA)参与从种子萌发到植物开花、结果和衰老等多个生长发育过程。研究ABA细胞信号转导的分子机制对进一步阐明其功能具有重要的意义。通过介绍FCA(Flowering Control Locus A)、Mg离子螯合酶H亚基(ABAR/CHLH)、G蛋白偶联受体(GCR2)、GTG1/GTG2(GPCR-type G-Proteins1/2)和PYR1/PYL/RCAR在ABA信号传导途径中的作用模式,阐述了其能够接受ABA信号并激活相关下游组分,从而完成其生理功能。
基金a grant from the Biogreen21 Program (PJ008222) Rural Development Administration and the Research Foundation of Korea (NFR) grant funded by the Korea government (No.2011-0007600)，the US National Science Foundation and Korean WCU Program of National Research Foundation (to S.L.).No conflict of interest declared
文摘Plant hormone abscisic acid （ABA） serves as an integrator of environmental stresses such as drought to trig-ger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1, an outward anion channel required for stomatal closure, was regulated via reversible protein phosphorylation events involving ABA signaling components, including protein phosphatase 2C members and a SnRK2-type kinase （OST1）. In this study, we reconstituted the ABA signaling pathway as a protein-protein interaction relay from the PYL/RCAR-type receptors, to the PP2C-SnRK2 phosphatase-kinase pairs, to the ion channel SLAC1. The ABA receptors interacted with and inhibited PP2C phosphatase activity against the SnRK2-type kinase, releasing active SnRK2 kinase to phosphorylate, and activate the SLAC1 channel, leading to reduced guard cell turgor and stomatal closure. Both yeast two-hybrid and bimolecular fluorescence complementation assays were used to verify the interactions among the components in the pathway. These biochemical assays demonstrated activity modifications of phosphatases and kinases by their interaction partners. The SLAC1 channel activity was used as an endpoint readout for the strength of the signaling pathway, depending on the presence of different combinations of signaling components. Further study using transgenic plants overexpressing one of the ABA receptors demonstrated that changing the relative level of interacting partners would change ABA sensitivity.
文摘Abscisic acid （ABA） is a major phytohormone involved in important stress-related and developmental plant processes. Membrane-delimited ABA signal transduction plays an important role in early ABA signaling, but the molecular mechanisms connecting core signaling components to the plasma membrane remain un- clear. Plants have evolved a large number of receptor-like kinases （RLKs） to modulate diverse biological processes by perceiving extracellular stimuli and activating downstream signaling responses. In this study, a putative leucine-rich repeat-RLK gene named RECEPTOR DEAD KINASE1 （AtRDK1） was identified and characterized in Arabidopsis thaliana. RDK1 promoter-GUS analysis revealed that RDK1 is expressed ubiq- uitously in the various tissues in Arabidopsis, and its expression is mainly induced by ABA. In the presence of ABA, RDKl-deficient rdkl-1 and rdkl-2 lines showed significant resistance in cotyledon greening and root growth, whereas RDKl-overexpressing lines showed enhanced sensitivity. Consistently, the expres- sion of ABA-responsive genes was significantly downregulated in rdkl mutant seedlings, which were also hypersensitive to drought stress with increased water loss. Interestingly, RDK1 was found to be an atypical kinase localized to the plasma membrane and did not require its kinase activity during ABA-mediated inhi- bition of seedling development. Accordingly, RDK1 interacted in the plasma membrane with type 2C protein phosphatase ABSClSIC ACID INSENSITIVE1 （ABI1）; this interaction was further enhanced by exogenous application of ABA, suggesting that RDKl-mediated recruitment of ABI1 onto the plasma membrane is important for ABA signaling. Taken together, these results reveal an important role for RDK1 in plant responses to abiotic stress conditions in an ABA-dependent manner.
文摘ABA是调控植物体生长发育和响应外界应激的重要植物激素之一。近年来, ABA受体的筛选和鉴定取得了突破性进展, 为植物中ABA信号转导通路的阐明奠定了重要基础。该文主要综述了ABA-binding protein/H subunit of Mg-chelatase (ABAR/CHLH)、G protein-coupled receptor 2 (GCR2)、GPCR-type G protein 1/2 (GTG1/2)和pyrabactin resistant/PYR-like/regulatory component of ABA (PYR/PYL/RCAR)被报道为ABA受体的研究历程, 重点介绍了以ABAR/CHLH和PYR/PYL/RCAR为受体的ABA信号转导通路模型的构建, 旨在为ABA受体及其信号转导通路的相关研究提供参考。
