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。     

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。     

脱落酸信号转导研究进展

对脱落酸受体、脱落酸调控基因表达、脱落酸信号调节分子以及保卫细胞中脱落酸信号调控的最新研究进展进行了综述.     

植物激素脱落酸受体及其信号转导途径研究进展

脱落酸是广泛存在于植物体的多功能激素,通过与体内受体及随后的复杂信号网络互作进而调节植物生长发育、抵御环境胁迫。脱落酸受体的筛选和鉴定一直备受关注,并已取得较大突破,其信号转导机制也再次成为人们研究的热点。对脱落酸受体的鉴定以及介导的信号转导途径方面最新进展进行了综述并展望,以期对相关研究领域提供参考。     

脱落酸应答基因的结构,表达调控及信号转导

许多脱落酸应答的基因已被克隆,并已研究了一些基因的调控。其启动子有G－box和ABARE顺式元件。ABARE与Leuzippier（亮氨酸拉链蛋白）互相作用,ABA与某些基因产物结合以及蛋白质磷酸化在基因表达调控中起重要作用。ABA涉及的信号转导是多途径或单途径的。文中讨论了ABA应答基因的结构、表达调控及信号转导的研究方向。     

始于质体/叶绿体的ABA信号通路

该文全面评述了植物激素脱落酸（ABA）受体的研究进展概况,重点介绍细胞内ABA受体ABAR/镁螯合酶H亚基CHLH对ABA信号感知和向下游转导的研究进展,总结了ABAR介导的、起始于质体/叶绿体的ABA信号通路。ABAR是一个跨越叶绿体被膜的蛋白质,其N-端和C-端暴露在细胞质中;ABAR在细胞质一侧的C-端部分与一组WRKY转录因子（WRKY18、WRKY40、WRKY60）相互作用。WRKY18、WRKY40和WRKY60是一组转录抑制因子。它们互相协作,抑制下游重要的ABA信号调节子基因（如ABI4、ABI5、ABF4和MYB2等）的表达,从而负调节ABA信号通路。WRKY40是其中的核心调节子,WRKY18协助加强WRKY40对ABA信号的负调节。ABAR与ABA信号分子结合后,可以刺激WRKY40从细胞核转移至细胞质,促进ABAR与WRKY40的相互作用;进而激发一种未知因子（或信号系统）,阻遏WRKY40的表达,从而解除WRKY40对ABA响应基因转录的抑制,最终实现ABA的生理效应。这些发现描述了一个从信号原初识别到下游基因表达的新的ABA信号通路。论文最后对未来该领域的研究方向进行了讨论。     

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。     

塔里木河下游干旱胁迫下的胡杨生理特点分析

本运用塔里木河下游地下水位变化资料和塔里木河下游主要植物胡杨脯氨酸和脱落酸(ABA)的分析实验数据,结合野外调查,对地下水位变化与胡杨体内脯氨酸和脱落酸积累的关系进行了分析。研究表明,在塔里木河下游,塔里木河下游胡杨体内的脯氨酸和脱落酸含量与地下水位变化密切相关．以胡杨为主的天然植物受干旱胁迫程度愈大,退化愈严重,而反映在胡杨体内脯氨酸和脱落酸含量上．则随着地下水位的下降、水分胁迫程度的增加呈现出明显增加态势。在不同地下水位埋深条件下,胡杨体内脯氨酸和脱落酸累积过程的变化和差异表达了胡杨受干旱的程度;塔里木河下游胡杨的生长发育已受到严重的十旱胁迫。     

不同籼稻品种的矮生性与内源ABA水平及其结合蛋白的关系

试验研究了内源脱落酸及其结合蛋白与含有不同矮秆主基因的籼稻矮生性状的关系。结果表明：籼稻的矮生性也受内源ＡＢＡ及其结合蛋白协同调控。矮秆品种幼苗内源ＡＢＡ及其幼芽膜上ＡＢＡ结合蛋白水平显著高于离秆品种,且含有强矮化效应的ｓｄ－ｇ基因的新桂矮、双矮的内源ＡＢＡ及其结合蛋白水平又明显高于含ｓｄ－１半矮秆基因的广场矮。外源ＡＢＡ能显著抑制籼稻幼苗伸长,苗高下降率与ＡＢＡ结合蛋白水平有一定的关系,且矮秆品     

植物ABA-H2O2介导的气孔关闭

本文综述了脱落酸作为根源信号物质经由木质部被传递到叶片,经重新分配再与脱落酸受体结合,然后刺激气孔开放因子,调节烟酰胺腺嘌呤二核苷酸磷酸氧化酶等关键酶活性产生过氧化氢,过氧化氢可使胞质碱化并刺激钙离子通道使钙离子内流,活化阴离子通道使阴离子外流,最终导致气孔关闭的一系列过程。该过程涉及到的因子包括：脱落酸受体、气孔开放因子、磷脂酰环己六醇、分裂原激活蛋白激酶、烟酰胺腺嘌呤二核苷酸磷酸氧化酶、Ca^（2＋）、pH、一氧化氮等。     

Stress-induced abscisic acid transients and stimulus-response-coupling

Loss of cell turgor and distortion of the plasma membrane occur as a result of dehydration and precede the stress-induced bulk increase in concentration of tissue abscisic acid. The latter has been correlated with induction of stress-related gene expression. However, several different stresses may trigger the same coupling mechanism. Thus, at least three signalling pathways have been proposed: abscisic acid-requiring, abscisic acid-responsive, and mechanosensory. In this paper, the role and contribution of stress-induced abscisic acid transients is examined in an attempt to explain apparent abscisic acid-dependent and -independent stimulus-response-coupling. Early, intermediate, and late response stages are defined within the stress-induced abscisic acid transient and at least four signalling mechanisms are identified. These include, early and late intracellular modulation of gene expression through depression and/or negative regulation, rapid membrane-initiated calcium release and ion channel activation, and late (slow) hormone-receptor induction of gene expression. An assessment of these proposed ABA signalling mechanisms in terms of AABA-dependent and -independent stimulus-response-coupling strongly suggests that rapid responses may not be a prerequisite for slow responses and that the receptor proteins involved have different steric requirements, i.e., they are tissue- and/or cell-specific.     

脱落酸信号转导研究进展

脱落酸（ABA）对植物生长发育和适应环境胁迫等多方面有重要的调节作用,其信号转导机制非常引人注目,近年来这方面研究进展很快,本文利用现有文献,对脱落酶不敏感和超敏感性突变体,脱落酸的结合位点与受体,ABA信号转涉及的细胞第二信使（Ca^2 ,磷酸肌醇,cADPR,阴离子通道与H^ ), 蛋白质可逆磷酸化以及ABA诱导基因表达所必需的顺序作用元件（cis-acting elenment)和反式作用因子（trans-acting factor)等几方面的最新研究进展作了介绍。     

Identification of jasmonic acid in Mimosa pudica and its inhibitory effect on auxin- and light-induced opening of the pulvinules

Jasmonic acid was identified from Mimosa pudica L. plants by mass spectrometry, high performance liquid chromatography and thin layer chromatography. Effects of authentic jasmonic acid on pulvinule movement and transpiration of the pinnae were compared with those of abscisic acid. Jasmonic acid and abscisic acid each at 10⁻⁵ M inhibited both auxin- and light-induced opening of the pulvinules. A closure-inducing activity of jasmonic acid at 10⁻⁴ M was greater than that of abscisic acid at 10⁻⁴ M. Pinnae transpiration was reduced by 10⁻⁵ M abscisic acid but not by 10⁻⁴ M jasmonic acid.     

A radioimmunoassay for abscisic acid

We have developed a radioimmunoassay (RIA) for abscisic acid (ABA) in the 0.1 ng to 2.5 ng range. Antibodies were obtained from rabbits immunized with ABA bound via its carboxyl group to bovine serum albumin. Cross-reactivity studies indicate that ABA esters are completely cross-reactive with ABA, while trans, trans abscisic acid (t-ABA) phaseic acid (PA) and dihydrophaseic acid (DPA) have much lower but significant cross-reactivities. Purification methods which reduce the levels of cross-reacting substances are described.Abbreviations RIA radioimmunoassay - DPA 4-dihydrophaseic acid - PA phaseic acid - GC gas chromatography - HPLC high performance liquid chromatography - TLC thin-layer chromatography - BSA bovine serum albumin - ABA abscisic acid - t-ABA trans, trans abscisic acid - IAA indoleacetic acid     

真菌中脱落酸的代谢及定量分析技术

综述了各种脱落酸产生真菌的生物学特征及其不同的生物合成代谢途径,并对脱落酸的定量分析技术作了简要介绍。     

The molecular genetics of seed maturation in maize

The maturation phase of seed formation involves coordinated expression of multiple developmental pathways. These processes include abscisic acid regulated responses associated with the arrest of embryo development and induction of anthocyanin synthesis in embryo and aleurone tissues. Studies of the maturation defective vivaparous mutants of maize suggest that one gene, viviparous-1 ( vpl ), regulates both of these pathways in the developing seed. Mutations at vpl reduce the sensitivity of the developing embryo to abscisic acid. In addition, Vpl is required for expression of Cl , a regulatory gene for the anthocyanin pathway. This interaction is consistent with the idea that Vpl and Cl function as part of a regulatory hierarchy controlling seed development. Molecular studies of vpl mutations which separate control of embryo arrest and anthocyanin synthesis suggest that these functions map to discrete domains in the Vpl protein. Therefore, coordinate control of diverse maturation processes may be achieved through expression of a functionally complex regulatory molecule.     

Carotenogenic and abscisic acid biosynthesizing activity in a cell-free system

Abscisic acid is considered an apocarotenoid formed by cleavage of a C-40 precursor and subsequent oxidation of xanthoxin and abscisic aldehyde. Confirmation of this reaction sequence is still awaited, and might best be achieved using a cell-free system capable of both carotenoid and abscisic acid biosynthesis. An abscisic acid biosynthesizing cell-free system, prepared from flavedo of mature orange fruits, was used to demonstrate conversion of farnesyl pyrophosphate, geranylgeranyl pyrophosphate and all-trans-β-carotene into a range of β,β-xanthophylls, xanthoxin, xanthoxin acid, 1′,4′-trans-abscisic acid diol and abscisic acid. Identification of product carotenoids was achieved by high-performance liquid chromatography and on-line spectral analysis of individual components together with co-chromatography. Putative C-15 intermediates and product abscisic acid were identified by combined capillary gas chroma-tography-mass spectrometry. Kinetic studies revealed that β-carotene, formed from either famesyl pyrophosphate or geranylgeranyl pyrophosphate, reached a maximum within 30 min of initiation of the reaction. Thereafter, β-carotene levels declined exponentially. Catabolism of substrate β-carotene into xanthophylls, putative abscisic acid precursors and product abscisic acid was restricted to the all-trans-isomer. However, when a combination of all-trans- and 9-cis-β-carotene in the ratio 1:1 was used as substrate, formation of abscisic acid and related metabolites was enhanced. Biosyn-thetically prepared [¹⁴C]-all-trans-violaxanthin, [¹⁴C]-all-trans-neoxanthin and [¹⁴C]-9′-cis-neoxanthin were used as substrates to confirm the metabolic interrelationship between carotenoids and abscisic acid. The results are consistent with 9′-cis-neoxan-thin being the immediate carotenoid precursor to ABA, which is oxidatively cleaved to produce xanthoxin. Formation of abscisic aldehyde was not observed. Rather, xanthoxin appeared to be converted to abscisic acid via xanthoxin acid and 1′,4′-trans-abscisic acid diol. An alternative pathway for abscisic acid biosynthesis is therefore proposed.