植物激素脱落酸受体的研究进展

脱落酸（abscisic acid,ABA）广泛参与植物生长发育的调控和对多种环境胁迫的适应性反应。有关ABA受体的研究已经在检测受体位置、纯化ABA特异性的结合蛋白和克隆ABA受体基因方面做出了许多重要的工作。最近相继发现一种RNA结合蛋白FCA和一种编码Mg离子螯合酶（Mg-chelatase）H亚基的CHLH作为两种不同的ABA受体分别调控植物的开花时间和介导种子萌发、幼苗生长及叶片的气孔运动。本文从实验策略的角度重点分析总结了研究脱落酸受体相对有效的途径与方法,同时就有关的研究结果给予了评论和展望。     

PYR/PYL/RCAR蛋白介导植物ABA的信号转导

脱落酸(ABA)在各个植物生长发育阶段以及植物对生物与非生物胁迫的响应过程中都发挥着重要的作用。最近研究表明, 在ABA信号转导途径中有3种核心组份：ABA受体PYR/PYL/RCAR蛋白、负调控因子2C类蛋白磷酸酶(PP2C)和正调控因子SNF1相关的蛋白激酶2(SnRK2), 它们共同组成了一个双重负调控系统-- PYR/PYL/RCAR-| PP2C-| SnRK2来调控ABA信号转导及其下游反应, 且3种核心组份在植物体内的结合方式受时空和生化等因素的影响, 通过特定组合形成的ABA信号转导复合体介导特定的ABA信号反应。文章就PYR/PYL/RCAR蛋白介导的植物ABA信号识别与转导途径的分子基础及其调控机制, 以及PYR/PYL/RCAR-PP2C-SnRK2参与的ABA信号调控网络等研究进展做一概述, 并对该领域今后的研究进行了展望。     

PYR/PYL/RCAR蛋白介导植物ABA的信号转导

脱落酸(ABA)在各个植物生长发育阶段以及植物对生物与非生物胁迫的响应过程中都发挥着重要的作用。最近研究表明,在ABA信号转导途径中有3种核心组份:ABA受体PYR/PYL/RCAR蛋白、负调控因子2C类蛋白磷酸酶(PP2C)和正调控因子SNF1相关的蛋白激酶2(SnRK2),它们共同组成了一个双重负调控系统——PYR/PYL/RCAR—|PP2C—|SnRK2来调控ABA信号转导及其下游反应,且3种核心组份在植物体内的结合方式受时空和生化等因素的影响,通过特定组合形成的ABA信号转导复合体介导特定的ABA信号反应。文章就PYR/PYL/RCAR蛋白介导的植物ABA信号识别与转导途径的分子基础及其调控机制,以及PYR/PYL/RCAR—PP2C—SnRK2参与的ABA信号调控网络等研究进展做一概述,并对该领域今后的研究进行了展望。     

脱落酸的信号转导途径

脱落酸（ABA）是一种重要的植物激素,参与了种子萌发、气孔关闭及植物抗逆等多种生理过程。最新研究鉴定了ABA的三种类型受体,即FCA、CHLH和GCR2,特别是GCR2介导的信号转导（包括G蛋白偶联受体、G蛋白、相关靶酶等）研究取得重大突破,使人们对ABA的作用机制有了全面理解,从而为农业应用奠定了坚实基础。     

保卫细胞中ABA信号调控机制研究进展

脱落酸(ABA)具有调节植物快速响应逆境的重要功能。植物细胞中ABA核心信号通路由ABA受体PYR1/PYLs/ RCARs、A类碱性蛋白磷酸酶PP2Cs和Snf1相关蛋白激酶SnRK2s组成。活性氧(ROS)和Ca²⁺是保卫细胞中的重要第二信使, 调控ABA诱导的气孔关闭。该文对保卫细胞中核心ABA信号蛋白的调控以及ROS和Ca²⁺介导的ABA信号转导等最新研究成果进行综述, 旨在阐明保卫细胞中ABA信号调控机制。     

基于等温滴定微量热技术的玉米脱落酸受体检测体系

脱落酸(ABA)是响应逆境胁迫及调控植物生长发育的重要激素,其受体的发现以及在不同植物中的比较研究具有重要的理论与实际意义。等温滴定微量热技术(ITC)是鉴定和筛选ABA受体的重要技术之一,该方法对受体蛋白的纯度和生物活性要求较高。该文探讨了超声波破碎条件对受体蛋白得率以及ABA和受体蛋白浓度对二者亲和力的影响。结果表明,通过超声波破碎获得的原核表达玉米(Zea mays)ABA受体蛋白Zm PYL1含量高,蛋白质图谱条带清晰。超声波破碎适宜的条件为:菌悬液浓度100 mg·m L–1,破碎总时长15分钟,单次破碎时长为3秒,间歇时长10秒;ITC检测结果发现,(±)-ABA与玉米受体Zm PYL1的结合反应为吸热过程,推测该受体蛋白Zm PYL1为二聚体,4 mmol·L–1(±)-ABA与0.1 mmol·L–1受体蛋白Zm PYL1反应结合效果较好,反应的解离常数Kd值为72.46μmol·L–1。研究结果为筛选和鉴定植物ABA受体奠定了重要技术基础。     

脱落酸对植物抗逆性影响的研究进展

脱落酸（ABA）是一种重要的植物激素,受到生物胁迫和非生物胁迫的调控,在植物对胁迫环境抗逆性中发挥重要作用。综述了近些年来国内外有关ABA生理功能抗逆性研究的一些最新进展,重点介绍ABA在植物干旱、高盐、低温、病虫害等逆境胁迫反应中起重要作用,在植物保护和农林业生产中的应用有重要意义。     

泛素化修饰调控脱落酸介导的信号途径

泛素化修饰是一种重要的蛋白质翻译后修饰,通过调节蛋白的活性和稳定性等影响其功能的发挥,在真核生物的生命过程中具有非常重要的作用。泛素化修饰通过精细地调控植物激素脱落酸(abscisic acid, ABA)的合成和信号转导过程的关键因子,影响植物对ABA的响应,参与植物生长发育过程及对干旱、盐和冷胁迫等不良环境的应答。本文概述了植物中泛素化修饰的相关组分(包括泛素连接酶E3、泛素结合酶E2、26S蛋白酶体)和内膜运输相关蛋白,以及这些蛋白调控ABA合成和信号转导过程的最新研究进展,提出该研究领域需要解决的新问题,以期为相关领域的科研人员进一步了解翻译后修饰如何调控激素信号的转导途径提供参考。     

植物脱落酸PYR/PYL/RCAR受体

脱落酸(abscisic acid,ABA)对植物生长发育、生物与非生物胁迫的应答具有重要作用。近年研究发现ABA在植物体中引起的信号通路源于其受体的参与,以ABA受体及ABA信号通路为基础的研究成为新的研究热点。本文简略介绍了ABA受体的研究进展概况,重点介绍细胞内ABA受体PYR/PYL/RCAR蛋白对ABA信号感知和下游转导的研究进展,最后总结了PYR/PYL/RCAR介导的ABA信号通路。     

脱落酸（ABA） 受体的研究进展

植物激素脱落酸(ABA)在植物对逆境适应及种子发育过程中具有重要的生理功能。尽管ABA作用的分子机制还不清楚,ABA受体还未得到鉴定,但近年来对ABA结合蛋白的研究取得了可喜的进展,已在多种植物中证明存在与ABA有高亲和力的结合蛋白。ABA的识别到底发生在胞外还是胞内,近几年随着微注射技术的应用,也得到不少实验证据。ABA信号的转导途径,特别是位于下游区域参与信号传递的物质的研究取得重大进展,其中以ABA调节气孔保卫细胞开关的信号传递成为研究这一领域的模式体系。     

ABA信号通路的起源与进化

植物激素脱落酸（abscisic acid,ABA）在植物的生长、发育和胁迫反应方面起重要的调控作用,其信号转导通路由4个核心组分共同组成一个双重负调控系统（PYR/PYL/RCAR—| PP2C—| SnRK2—ABF/AREB）,调控ABA应答反应。本文在综述和分析ABA信号通路4个核心组分的起源与进化的基础上,初步提出ABA信号通路的起源与进化路径：A类PP2C、第Ⅲ亚类SnRK2以及转录因子AREB/ABF在水生植物轮藻中已经进化产生,当陆生植物进化产生ABA受体PYR/PYL/RCAR后,即与其它3个组分形成完整的ABA信号通路。在植物进化过程中,ABA信号通路4个核心组分各家族成员的数量（亚类）呈递增趋势。     

蛋白质翻译后修饰在ABA信号转导中的作用

脱落酸(ABA)是植物生长发育和逆境适应过程中非常关键的植物激素。植物响应ABA信号转导过程由信号识别、转导及响应级联完成, 其中心转导途径由ABA受体RCAR/PYR/PYLs、磷酸酶PP2Cs、激酶SnRK2s、转录因子和离子通道蛋白构成。蛋白磷酸化、泛素化、类泛素化和氧化还原等翻译后修饰在ABA转导途径中起重要作用。该文综述了翻译后修饰在ABA信号转导中的作用。     

蛋白质翻译后修饰在ABA信号转导中的作用

脱落酸(ABA)是植物生长发育和逆境适应过程中非常关键的植物激素。植物响应ABA信号转导过程由信号识别、转导及响应级联完成, 其中心转导途径由ABA受体RCAR/PYR/PYLs、磷酸酶PP2Cs、激酶SnRK2s、转录因子和离子通道蛋白构成。蛋白磷酸化、泛素化、类泛素化和氧化还原等翻译后修饰在ABA转导途径中起重要作用。该文综述了翻译后修饰在ABA信号转导中的作用。     

Action of natural abscisic acid precursors and catabolites on abscisic acid receptor complexes

The phytohormone abscisic acid (ABA) regulates stress responses and controls numerous aspects of plant growth and development. Biosynthetic precursors and catabolites of ABA have been shown to trigger ABA responses in physiological assays, but it is not clear whether these are intrinsically active or whether they are converted into ABA in planta. In this study, we analyzed the effect of ABA precursors, conjugates, and catabolites on hormone signaling in Arabidopsis (Arabidopsis thaliana). The compounds were also tested in vitro for their ability to regulate the phosphatase moiety of ABA receptor complexes consisting of the protein phosphatase 2C ABI2 and the coreceptors RCAR1/PYL9, RCAR3/PYL8, and RCAR11/PYR1. Using mutants defective in ABA biosynthesis, we show that the physiological activity associated with ABA precursors derives predominantly from their bioconversion to ABA. The ABA glucose ester conjugate, which is the most widespread storage form of ABA, showed weak ABA-like activity in germination assays and in triggering ABA signaling in protoplasts. The ABA conjugate and precursors showed negligible activity as a regulatory ligand of the ABI2/RCAR receptor complexes. The majority of ABA catabolites were inactive in our assays. To analyze the chemically unstable 8'- and 9'-hydroxylated ABA catabolites, we used stable tetralone derivatives of these compounds, which did trigger selective ABA responses. ABA synthetic analogs exhibited differential activity as regulatory ligands of different ABA receptor complexes in vitro. The data show that ABA precursors, catabolites, and conjugates have limited intrinsic bioactivity and that both natural and synthetic ABA-related compounds can be used to probe the structural requirements of ABA ligand-receptor interactions.     

Abscisic acid receptors: multiple signal-perception sites

BACKGROUND AND AIMS: The phytohormone abscisic acid (ABA) plays a vital role in various aspects of plant growth and development and in adaptation of plants to various environmental stresses. Cell response to ABA is initiated by ABA perception with a cell receptor. Recently, three distinct ABA receptors have been identified, opening a door to uncover the initial events of ABA signal transduction. The aim of this Botanical Briefing is to present a perspective of the ABA receptors identified. SCOPE: This Briefing offers an introduction to the three ABA receptors identified and an analysis of the complexity and multiplicity of ABA receptors, and provides some viewpoints on future research.     

植物ABA受体及其介导的信号转导通路

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 Mgchelatase (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 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。     

The putative glutamate receptor 1.1 (AtGLR1.1) in Arabidopsis thaliana regulates abscisic acid biosynthesis and signaling to control development and water loss

The involvement of the putative glutamate receptor 1.1 (AtGLR1.1) gene in the regulation of abscisic acid (ABA) biosynthesis and signaling was investigated in Arabidopsis. Seeds from AtGLR1.1-deficient (antiAtGLR1.1) lines had increased sensitivity to exogenous ABA with regard to the effect of the hormone on the inhibition of seed germination and root growth. Seed germination, which was inhibited by an animal ionotropic glutamate receptor antagonist, 6,7-dinitroquinoxaline-2,3-[1H,4H]-dione, was restored by co-incubation with an inhibitor of ABA biosynthesis, fluridone. These results confirm that germination in antiAtGLR1.1 lines was inhibited by increased ABA. When antiAtGLR1.1 and WT seeds were co-incubated in fluridone and exogenous ABA, the antiAtGLR1.1 seeds were more sensitive to ABA. In addition, the antiAtGLR1.1 lines exhibited altered expression of ABA biosynthetic (ABA) and signaling (ABI) genes, when compared with WT. Combining the physiological and molecular results suggest that ABA biosynthesis and signaling in antiAtGLR1.1 lines are altered. ABA levels in leaves of antiAtGLR1.1 lines are higher than those in WT. In addition, the antiAtGLR1.1 lines had reduced stomatal apertures, and exhibited enhanced drought tolerance due to deceased water loss compared with WT lines. The results from these experiments imply that ABA biosynthesis and signaling can be regulated through AtGLR1.1 to trigger pre- and post-germination arrest and changes in whole plant responses to water stress. Combined with our earlier results, these findings suggest that AtGLR1.1 integrates and regulates the different aspects of C, N and water balance that are required for normal plant growth and development.     

The root of ABA action in environmental stress response

The growth and development of plants are influenced by the integration of diverse endogenous and environmental signals. Acting as a mediator of extrinsic signals, the stress hormone, abscisic acid (ABA), has been shown to regulate many aspects of plant development in response to unfavourable environmental stresses, allowing the plant to cope and survive in adverse conditions, such as drought, low or high temperature, or high salinity. Here, we summarize recent evidence on the roles of ABA in environmental stress responses in the Arabidopsis root; and on how ABA crosstalks with other phytohormones to modulate root development and growth in Arabidopsis. We also review literature findings showing that, in response to environmental stresses, ABA affects the root system architecture in other plant species, such as rice.     

AtRAE1 is involved in degradation of ABA receptor RCAR1 and negatively regulates ABA signalling in Arabidopsis

The phytohormone abscisic acid (ABA) plays an important role in regulating plant growth, development, and adaption to various environmental stresses. Regulatory components of ABA receptors (RCARs, also known as PYR/PYLs) sense ABA and initiate ABA signalling through inhibiting the activities of protein phosphatase 2C in Arabidopsis. However, the way in which ABA receptors are regulated is not well known. A DWD protein AtRAE1 (for RNA export factor 1 in Arabidopsis), which may act as a substrate receptor of CUL4–DDB1 E3 ligase, is an interacting partner of RCAR1/PYL9. The physical interaction between RCAR1 and AtRAE1 is confirmed in vitro and in vivo. Overexpression of AtRAE1 in Arabidopsis causes reduced sensitivity of plants to ABA, whereas suppression of AtRAE1 causes increased sensitivity to ABA. Analysis of protein stability demonstrates that RCAR1 is ubiquitinated and degraded in plant cells and AtRAE1 regulates the degradation speed of RCAR1. Our findings indicate that AtRAE1 likely participates in ABA signalling through regulating the degradation of ABA receptor RCAR1.