植物CBL-CIPK信号系统的功能及其作用机理

由类钙调磷酸酶B蛋白CBLs及其互作蛋白激酶CIPKs组成的信号系统是植物逆境胁迫信号传导的关键调控节点,是近几年植物逆境胁迫生理与分子生物学研究领域中的重要热点之一。文章主要介绍了CBLs和CIPKs基本功能结构域、CBL-CIPK信号系统在各种生物和非生物逆境胁迫响应、营养物质吸收及植物激素应答中的生物学功能及其作用机理。     

植物蛋白激酶与作物非生物胁迫抗性的研究

干旱、盐碱、高温等非生物逆境胁迫严重影响作物生长发育、产量和品质。在遭受非生物逆境的威胁时,植物通过信号受体,可感知、转导胁迫信号,启动一系列抗逆相关基因的表达,最终缓解或抵御非生物逆境胁迫对植物造成的危害。其中,蛋白激酶和蛋白磷酸酯酶的磷酸化/去磷酸化作用在植物感受外界胁迫信号的分子传递过程中起到开关的作用。正常情况下,蛋白激酶磷酸化开启信号转导途径,启动相应的抗逆基因表达反应;当信号消失后,蛋白激酶去磷酸化将信号转导途径关闭,达到调控植物正常生长的目的。因此,蛋白激酶在调控感受胁迫信号、启动各种非生物逆境胁迫响应中起到了极其重要的作用。近年来,对植物蛋白激酶参与非生物胁迫响应的研究倍受关注。本文阐述了不同类型蛋白激酶在改良作物非生物胁迫抗性上的应用,为进一步研究提供资料。     

植物响应非生物胁迫的磷酸化修饰组学研究进展

植物具有固着生活的特点,高温、低温、干旱和盐等生境中常见的非生物胁迫会严重影响植物的生长发育。蛋白质磷酸化是植物应对非生物胁迫的重要机制,主要通过蛋白质的磷酸化和去磷酸化修饰来调控植物细胞对外界胁迫的应激反应,在植物细胞快速传递胁迫信号并激活对胁迫环境的形态、生理和分子水平适应机制的过程中起重要作用。该文主要介绍了植物磷酸化蛋白质的富集、检测和鉴定技术,并对近年来国内外有关植物响应高温、低温、干旱、淹水、盐、养分亏缺和元素毒害等非生物胁迫的磷酸化修饰蛋白组学研究进展进行综述。     

赤霉素信号在非生物胁迫中的作用及其调控机制研究进展

赤霉素(GA)能促进种子萌发和植物生长发育。近年来的研究表明赤霉素这一激素在植物响应非生物胁迫中同样发挥着重要的作用。植物通过调节GA生物合成、信号转导及其生物活性提高胁迫耐受性。综述了赤霉素在应对常见的几类非生物胁迫中所起的作用,分析了其合成、信号转导通路调控机制以及赤霉素与其他激素在响应非生物胁迫的关系。     

禾本科植物响应非生物胁迫的转录调控网络

分子和遗传研究表明,转录因子在响应非生物胁迫的基因表达调控中起着重要的作用,并且大部分转录因子在禾本科植物和拟南芥中是相同的.禾本科植物包括许多重要的农作物,对禾本科植物的转录因子进行研究,可增强重要农作物对非生物胁迫的耐受性.综述了禾本科植物响应非生物胁迫的转录调控网络,包括响应寒冷胁迫的DREB1/CBF调节子、响应脱水和高盐胁迫的DREB2调节子,ABA介导反应的ABRE及其伴侣元件、响应ABA的AREB/ABF调节子,响应脱水、高盐和寒冷胁迫的NAC调节子.     

miR398在植物逆境胁迫应答中的作用

MicroRNA (miRNA)是一类新型的调控基因表达的小分子RNA, 它作为基因表达的负调控因子, 在转录后水平调节靶基因的表达。miRNA参与调控植物的生长发育, 并在多种非生物与生物胁迫响应中发挥重要作用。miR398是第一个被报道的受氧化胁迫负调控的miRNA。它通过负调控其靶基因Cu/Zn过氧化物歧化酶(Cu/Zn-superoxide dismutase, CSD)的表达, 在多种逆境胁迫响应中扮演重要角色, 如调节铜代谢平衡, 应答重金属、蔗糖、臭氧等非生物胁迫, 以及参与应答生物胁迫等。文章综述了miR398在多种逆境胁迫响应中重要的调节作用及miR398自身的转录调控。     

表观遗传调控植物响应非生物胁迫的研究进展

植物的生长发育容易受到外界环境变化的影响。非生物胁迫发生时, 表观遗传机制对胁迫应答基因的表达调控发挥了十分重要的作用。近年来, 调控植物非生物胁迫应答的表观遗传机制研究取得了一系列重要进展, 为进一步深入解析植物响应非生物胁迫的分子机制奠定了基础。该文对DNA甲基化修饰、组蛋白修饰、染色质重塑和非编码RNA等主要表观遗传调控方式在植物响应非生物胁迫中的作用进行了简要综述。     

MAPK级联及其在植物抗病防卫反应中的研究进展

促分裂原活化蛋白激酶(MAPK)级联信号转导途径参与了生物体生长发育和抗逆胁迫生理。植物MAPK级联途径一般由三个丝氨酸/苏氨酸蛋白激酶组分构成:包括MAPKKK(MEKK、MAP3K)、MAPKK(MEK)和MAPK。植物在响应外界环境刺激时,MAPKKK首先被自磷酸化激活,依次通过磷酸化激活MAPKK和MAPK,进而将外界信号在细胞内传递从而调控目标基因的表达。MAPK级联途径参与植物激素、生物胁迫、非生物胁迫等过程的信号传递,本文就MAPK级联途径在植物抗病防卫反应中的研究进展进行综述。     

水杨酸对非生物胁迫下植物抗氧化能力的影响

水杨酸(SA)在植物体内具有重要生理作用,除了参与抵抗生物胁迫信号转导外,还参与植物响应非生物胁迫。外源SA在植物应对盐碱、重金属、高低温和干旱等胁迫过程中发挥关键作用。综述了SA调控的抗氧化系统对植物响应非生物胁迫的影响,重点讨论了SA对抗氧化酶和非酶物质的诱导作用。     

Evolutionary analysis of CBL-interacting protein kinase gene family in plants

Calcineurin B-like proteins (CBLs) and CBL-interacting protein kinases (CIPKs) form the CBL-CIPK complexes, perceiving calcium signals and relaying the signals to downstream responses in plants. To further understand the CBL-CIPK signaling system, here we focused on the evolutionary analysis of CIPKs. We re-evaluated eight plant genomes and identified 146 CIPKs, providing several new CIPKs in rice and poplar. A phylogenetic tree was constructed, showing that these 146 CIPKs are grouped into intron-rich and intron-less clades. Furthermore, all the CIPKs from the non-angiosperm species were found in intron-rich clade. We identified 30 conserved protein motifs among these 146 CIPKs. Analysis of gene duplication showed that the expansion of CIPKs in both clades is partly contributed by segmental duplications, however, tandem duplicates were found only in intron-less clade. Ka/Ks ratios showed that CIPK genes have experienced purifying selective pressure. Additionally, clustering of gene expression revealed that some CIPK genes in two clades share similar expression patterns under abiotic stresses and four CIPKs in intron-less clade form a distinct cluster (i.e., different expression patterns), suggesting the complexity of CIPK gene expression under abiotic stresses. Taken together, our results provided some new insights into the evolution of CIPKs and the hint that the expansion of CIPKs in intron-less clade is adaptive to environmental stresses.     

Structure and function of the CBL–CIPK Ca2+-decoding system in plant calcium signaling

Calcium is a crucial messenger in many growth and developmental processes in plants. The central mechanism governing how plant cells perceive and respond to environmental stimuli is calcium signal transduction, a process through which cellular calcium signals are recognized, decoded, and transmitted to elicit downstream responses. In the initial decoding of calcium signals, Ca²⁺ sensor proteins that bind Ca²⁺ and activate downstream signaling components are implicated, thereby regulating specific physiological and biochemical processes. After calcineurin B-like proteins (CBLs) sense these Ca²⁺ signatures, these proteins interact selectively with CBL-interacting protein kinases (CIPKs), thereby forming CBL/CIPK complexes, which are involved in decoding calcium signals. Therefore, specificity, diversity, and complexity are the main characteristics of the CBL-CIPK signaling system. However, additional CBLs, CIPKs, and CBL/CIPK complexes remain to be identified in plants, and the specific functions of their abiotic and biotic stress signaling will need to be further dissected. Therefore, a much-needed synthesis of recent findings is important to further the study of CBL-CIPK signaling systems. Here, we review the structure of CBLs and CIPKs, discuss the current knowledge of CBL–CIPK pathways that decode calcium signals in Arabidopsis, and link plant responses to a variety of environmental stresses with specific CBL/CIPK complexes. This will provide a foundation for future research on genetically engineered resistant plants with enhanced tolerance to various environmental stresses.     

Identification and characterization of putative CIPK genes in maize

Calcium(Ca) plays a crucial role as a second messenger in intracellular signaling elicited by developmental and environmental cues. Calcineurin B-like proteins(CBLs) and their target proteins,CBL-interacting protein kinases(CIPKs) have emerged as a key Ca~(2+)-mediated signaling network in response to stresses in plants.Bioinformatic analysis was used to identify 43 putative ZmCIPK(Zea mays CIPK) genes in the genome of maize inbred line B73.Based on gene structures,these ZmCIPKs were divided into intron-...     

Comprehensive structural,interaction and expression analysis of CBL and CIPK complement during abiotic stresses and development in rice

Calcium ion is involved in diverse physiological and developmental pathways. One of the important roles of calcium is a signaling messenger, which regulates signal transduction in plants. CBL (calcineurin B-like protein) is one of the calcium sensors that specifically interact with a family of serine–threonine protein kinases designated as CBL-interacting protein kinases (CIPKs). The coordination of these two gene families defines complexity of the signaling networks in several stimulus-response-coupling during various environmental stresses. In Arabidopsis, both of these gene families have been extensively studied. To understand in-depth mechanistic interplay of CBL–CIPK mediated signaling pathways, expression analysis of entire set of CBL and CIPK genes in rice genome under three abiotic stresses (salt, cold and drought) and different developmental stages (3-vegetative stages and 11-reproductive stages) were done using microarray expression data. Interestingly, expression analysis showed that rice CBLs and CIPKs are not only involved in the abiotic stress but their significant role is also speculated in the developmental processes. Chromosomal localization of rice CBL and CIPK genes reveals that only OsCBL7 and OsCBL8 shows tandem duplication among CBLs whereas CIPKs were evolved by many tandem as well as segmental duplications. Duplicated OsCIPK genes showed variable expression pattern indicating the role of gene duplication in the extension and functional diversification of CIPK gene family in rice. Arabidopsis SOS3/CBL4 related genes in rice (OsCBL4, OsCBL5, OsCBL7 and OsCBL8) were employed for interaction studies with rice and Arabidopsis CIPKs. OsCBLs and OsCIPKs are not only found structurally similar but likely to be functionally equivalent to Arabidopsis CBLs and CIPKs genes since SOS3/CBL4 related OsCBLs interact with more or less similarly to rice and Arabidopsis CIPKs and exhibited an interaction pattern comparable with Arabidopsis SOS3/CBL4.     

The Arabidopsis calcium sensor calcineurin B-like 3 inhibits the 5'-methylthioadenosine nucleosidase in a calcium-dependent manner

Calcineurin B-like (CBL) proteins represent a unique family of calcium sensors in plant cells. Sensing the calcium signals elicited by a variety of abiotic stresses, CBLs transmit the information to a group of serine/threonine protein kinases (CBL-interacting protein kinases [CIPKs]), which are currently known as the sole targets of the CBL family. Here, we report that the CBL3 member of this family has a novel interaction partner in addition to the CIPK proteins. Extensive yeast two-hybrid screenings with CBL3 as bait identified an interesting Arabidopsis (Arabidopsis thaliana) cDNA clone (named AtMTAN, for 5'-methylthioadenosine nucleosidase), which encodes a polypeptide similar to EcMTAN from Escherichia coli. Deletion analyses showed that CBL3 utilizes the different structural modules to interact with its distinct target proteins, CIPKs and AtMTAN. In vitro and in vivo analyses verified that CBL3 and AtMTAN physically associate only in the presence of Ca(2+). In addition, we empirically demonstrated that the AtMTAN protein indeed possesses the MTAN activity, which can be inhibited specifically by Ca(2+)-bound CBL3. Overall, these findings suggest that the CBL family members can relay the calcium signals in more diverse ways than previously thought. We also discuss a possible mechanism by which the CBL3-mediated calcium signaling regulates the biosynthesis of ethylene and polyamines, which are involved in plant growth and development as well as various stress responses.     

菜用大豆CIPK基因对逆境胁迫及激素的响应特征

CIPK(calcineurin B-like-interacting protein kinase)是一类丝氨酸/苏氨酸蛋白激酶,在植物响应逆境胁迫和激素信号转导中发挥重要作用。本研究利用大豆基因组数据库,在全基因组水平鉴定获得52个CIPK蛋白激酶。蛋白比对分析发现所有Gm CIPK含有高度保守特征性的N端激酶区、连接区和C端调控区。系统进化树分析发现大豆Gm CIPK与拟南芥、水稻CIPK分类一致,分为4个亚家族,且每个亚家族含有3个不同物种的成员,表明Gm CIPK基因的分化早于物种的分化。启动子分析表明,多数Gm CIPK基因的启动子区含有逆境和激素应答元件。组织表达分析发现,Gm CIPK基因呈现多样化的组织表达特性。进一步选取组织表达量相对较高的14个Gm CIPK进行荧光定量PCR分析,结果表明这些菜用大豆CIPK基因在不同程度上均受高温、干旱、高盐胁迫以及ABA、ACC、SA、Me JA激素的诱导表达。采用蛋白同源比对和蛋白互作在线数据库对拟南芥及大豆同源CIPK蛋白激酶与其他蛋白的互作关系进行了预测分析,发现17对同源CIPK与其他蛋白(激酶、磷酸酶、转录因子等)存在互作。本研究为菜用大豆CIPK基因的功能研究与利用奠定了基础。