BRs在植物响应非生物胁迫中的作用

油菜素甾体(brassinosteroids,BRs)是植物界普遍存在的一类多羟基化的植物甾体激素,不仅调节植物的生长发育过程,还参与植物对生物和非生物胁迫的响应.概述了BRs的生物合成途径以及信号转导途径,重点阐述了BRs参与非生物胁迫应答的分子机制,展望了BRs未来的研究方向,为深入理解BRs介导的非生物胁迫调控网...     

Comprehensive Expression Analysis of Rice Armadillo Gene Family During Abiotic Stress and Development

Genes in the Armadillo (ARM)-repeat superfamily encode proteins with a range of developmental and physiological processes in unicellular and multicellular eukaryotes. These 42 amino acid, long tandem repeat-containing proteins have been abundantly recognized in many plant species. Previous studies have confirmed that Armadillo proteins constitute a multigene family in Arabidopsis. In this study, we performed a computational analysis in the rice genome (Oryza sativa L. subsp. japonica), and identified 158 genes of Armadillo superfamily. Phylogenetic study classified them into several arbitrary groups based on a varying number of non-conserved ARM repeats and accessory domain(s) associated with them. An in-depth analysis of gene expression through microarray and Q-PCR revealed a number of ARM proteins expressing differentially in abiotic stresses and developmental conditions, suggesting a potential roles of this superfamily in development and stress signalling. Comparative phylogenetic analysis between Arabidopsis and rice Armadillo genes revealed a high degree of evolutionary conservation between the orthologues in two plant species. The non-synonymous and synonymous substitutions per site ratios (Ka/Ks) of duplicated gene pairs indicate a purifying selection. This genome-wide identification and expression analysis provides a basis for further functional analysis of Armadillo genes under abiotic stress and reproductive developmental condition in the plant lineage.     

Environmental perception avenues: the interaction of cytokinin and environmental response pathways

Cytokinins were discovered in the 1950s by their ability to promote cell division in cultured plant cells. Recently, there have been significant breakthroughs in our understanding of the biosynthesis, metabolism, perception and signal transduction of this phytohormone. These advances, coupled with physiological and other approaches, have enabled remarkable progress to be made in our understanding of the interactions between cytokinin function and environmental inputs. In this review, we first highlight the most recent advances in our understanding of cytokinin biosynthesis, metabolism and signalling. We then discuss how various environmental signals interact with these pathways to modulate plant growth, development and physiology.     

植物蛋白激酶介导盐旱胁迫与相关激素信号传导途径的研究进展

干旱、盐渍、低温和高温等非生物胁迫严重影响植物的生长发育和作物的产量。在长期的进化过程中,植物逐渐形成了对外部刺激快速感知和主动适应的能力,其中植物体内逆境信号的传递在植物快速感知外部刺激和主动适应非生物胁迫过程中起着非常重要的作用。蛋白激酶和蛋白磷酸酶催化的蛋白质磷酸化和去磷酸化是植物体内存在的最普遍且最重要的信号转导调节方式。其中,蛋白激酶的主要作用是将ATP或GTP上的γ磷酸基团转移到特定的底物蛋白上,使蛋白磷酸化,被磷酸化的蛋白发挥相应的生理功能。近年来,利用生物技术和基因工程等手段从细胞、分子水平上研究有关蛋白激酶的抗逆机理,通过基因沉默、基因过表达等策略提高植物的抗逆性成为国内外抗逆分子生物学与分子育种学研究的热点。本文主要对植物蛋白激酶在介导非生物胁迫和激素信号通路中的作用进行综述,为进一步研究植物蛋白激酶功能提供有价值的信息。     

类受体蛋白激酶与植物非生物胁迫应答

类受体蛋白激酶(receptor-like protein kinase,RLK)是植物信号转导网络中的重要成员,参与介导生长、发育以及逆境胁迫应答等多种细胞代谢过程．在植物细胞中已发现和克隆了富含亮氨酸重复区型(LRR)、凝集素型(lectin-like)和细胞壁相联型(WAK)等不同的RLK亚家族．这些RLK能够感受多种发育和外界环境胁迫信号, 并在植物对非生物胁迫的响应过程中发挥重要的调控作用．本文结合当今国内外研究进展,简述植物RLK的典型结构域特征,详细介绍多种RLK在植物逆境信号识别与转导中发挥的作用,同时对RLK在非生物胁迫应答中的具体作用机制进行了探讨．     

玉米类受体蛋白激酶基因ZmLRRPK1的cDNA克隆与表达分析

富亮氨酸重复区的类受体蛋白激酶(LRR-RLKs)在植物对多种信号的响应中发挥作用。应用电子克隆的方法在玉米中克隆了一个LRR-RLKs类基因的全长cDNA,命名为ZmLRRPK1（GenBank接受号为EU873320）。推断的ZmLRRPK1蛋白含有594个氨基酸,分子量为66kDa,等电点pI为5.42,具有典型的LRR-RLKs结构域。半定量RT-PCR结果表明,在ABA、甘露醇和氯化钠的诱导下,ZmLRRPK1在玉米胚芽鞘中表达并在24 h内保持较高的转录水平。     

橡胶草TkAPC10基因的鉴定及其表达模式分析

APC/C是一类泛素连接酶E3复合体,在调控细胞周期过程中发挥重要作用。为了揭示橡胶草APC/C蛋白复合体的功能,鉴定了橡胶草TkAPC10基因,并对其表达模式进行了分析,初步确定了其功能。TkAPC10基因的ORF为579 bp,编码192个氨基酸,其基因组DNA序列为1 092 bp,包含6个外显子和5个内含子。基因组分析发现,TkAPC10以单拷贝的形式存在,其启动子序列除了含有TATA-box和CAAT-box增强子元件外,还有ABA、JA、光以及逆境响应相关的顺式作用元件。系统进化关系分析发现,不同物种的APC10蛋白具有很高的同源性,TKAPC10与莴苣LsAPC10的相似性最高达到99%,而与其他菊科植物的APC10蛋白相似性也达到95%以上。进一步采用qRT-PCR技术对TKAPC10的表达模式进行分析,结果表明,该基因在细胞分裂旺盛的组织（花、叶和根）中的表达量显著高于细胞分裂活动相对缓慢的组织（花梗）。外源ABA处理后,TKAPC10基因转录水平显著下降;而MeJA和ET处理后,该基因显著上调表达。经PEG6000以及甘露醇处理后,TKAPC10表达水平显著下降;而...     

Rice Mitogen-activated Protein Kinase Gene Family and Its Role in Biotic and Abiotic Stress Response

The mitogen-activated protein kinase (MAPK) cascade is an important signaling module that transduces extracellu-lar stimuli into intracellular responses in eukaryotic organisms. An increasing body of evidence has shown that theMAPK-mediated cellular signaling is crucial to plant growth and development, as well as biotic and abiotic stressresponses. To date, a total of 17 MAPK genes have been identified from the rice genome. Expression profiling,biochemical characterization and/or functional analysis were carried out with many members of the rice MAPKgene family, especially those associated with biotic and abiotic stress responses. In this review, the phylogeneticrelationship and classification of rice MAPK genes are discussed to facilitate a simple nomenclature and standardannotation of the rice MAPK gene family. Functional data relating to biotic and abiotic stress responses are re-viewed for each MAPK group and show that despite overlapping in functionality, there is a certain level of functionalspecificity among different rice MAP kinases, The future challenges are to functionally characterize each MAPK, toidentify their downstream substrates and upstream kinases, and to genetically manipulate the MAPK signalingpathway in rice crops for the improvement of agronomically important traits.     

Reactive oxygen species mediate Na+-induced SOS1 mRNA stability in Arabidopsis

Salt Overly Sensitive 1 (SOS1), a plasma membrane Na⁺/H⁺ antiporter in Arabidopsis, is a salt tolerance determinant crucial for the maintenance of ion homeostasis in saline stress conditions. SOS1 mRNA is unstable at normal growth conditions, but its stability is substantially increased under salt stress and other ionic and dehydration stresses. In addition, H₂O₂ treatment increases the stability of SOS1 mRNA. SOS1 mRNA is inherently unstable and rapidly degraded with a half-life of approximately 10 min. Rapid decay of SOS1 mRNA requires new protein synthesis. Stress-induced SOS1 mRNA stability is mediated by reactive oxygen species (ROS). NADPH oxidase is also involved in the upregulation of SOS1 mRNA stability, presumably through the control of extracellular ROS production. The cis -element required for SOS1 mRNA instability resides in the 500-bp region within the 2.2 kb at the 3' end of the SOS1 mRNA. Furthermore, mutations in the SOS1 gene render sos1 mutants more tolerant to paraquat, a non-selective herbicide causing oxidative stress, indicating that SOS1 plays negative roles in tolerance of oxidative stress. A hypothetical model for the signaling pathway involving SOS1-mediated pH changes, NADPH oxidase activation, apoplastic ROS production and downstream signaling transduction is proposed, and the biological significance of ROS-mediated induction of SOS1 mRNA stability is discussed.     

Biotechnological implications from abscisic acid (ABA) roles in cold stress and leaf senescence as an important signal for improving plant sustainable survival under abiotic-stressed conditions

In the past few years, the signal transduction of the plant hormone abscisic acid (ABA) has been studied extensively and has revealed an unanticipated complex. ABA, characterized as an intracellular messenger, has been proven to act a critical function at the heart of a signaling network operation. It has been found that ABA plays an important role in improving plant tolerance to cold, as well as triggering leaf senescence for years. In addition, there have been many reports suggesting that the signaling pathways for leaf senescence and plant defense responses may overlap. Therefore, the objective was to review what is known about the involvement of ABA signaling in plant responses to cold stress and regulation of leaf senescence. An overview about how ABA is integrated into sugars and reactive oxygen species signaling pathways, to regulate plant cold tolerance and leaf senescence, is provided. These roles can provide important implications for biotechnologically improving plant cold tolerance.