Allantoin: Emerging Role in Plant Abiotic Stress Tolerance

Plant Molecular Biology Reporter - Allantoin is an intermediate product of purine catabolic pathway that helps in nitrogen mobilization in plants. It is ubiquitously present in the plant...     

赤霉素调节植物对非生物逆境的耐性

赤霉素（GAs）是一类重要的植物激素,调控植物生长发育的诸多方面．最近的研究表明,GA也参与对生物与非生物胁迫的响应,然而GA参与非生物胁迫响应的遗传学证据及其机制有待于进一步研究．本实验室前期研究证明,水稻EullfELONGATEDUPPERMOSTINTERNODE）通过一个新的生化途径降解体内的活性赤霉素分子,并参与调控水稻对病原菌的基础抗病性．本研究发现,euil突变体对盐胁迫能力降低,而超表达EUll基因的水稻和拟南芥耐盐性显著提高．进一步研究发现,积累高含量赤霉素的水稻euil突变体对脱落酸（ABA）的敏感性下降,而赤霉素缺失的EUll超表达转基因水稻和拟南芥均改变了对于ABA的敏感性．EUll基因的转录受逆境诱导,其功能缺失与超表达调控了逆境标志基因的表达．综上推测,GA可能是通过影响ABA的信号途径从而改变了植物对非生物胁迫的响应．     

Glutathione as an Antioxidant and Regulatory Molecule in Plants Under Abiotic Stress Conditions

The glutathione (GSH)/glutathione disulfide (GSSG) redox couple is involved in several physiologic processes in plants under both optimal and stress conditions. It participates in the maintenance of redox homeostasis in the cells. The redox state of the GSH/GSSG couple is defined by its reducing capacity and the half-cell reduction potential, and differs in the various organs, tissues, cells, and compartments, changing during the growth and development of the plants. When characterizing this redox couple, the synthesis, degradation, oxidation, and transport of GSH and its conjugation with the sulfhydryl groups of other compounds should be considered. Under optimal growth conditions, the high GSH/GSSG ratio results in a reducing environment in the cells which maintains the appropriate structure and activity of protein molecules because of the inhibition of the formation of intermolecular disulfide bridges. In response to abiotic stresses, the GSH/GSSG ratio decreases due to the oxidation of GSH during the detoxification of reactive oxygen species (ROS) and changes in its metabolism. The lower GSH/GSSG ratio activates various defense mechanisms through a redox signalling pathway, which includes several oxidants, antioxidants, and stress hormones. In addition, GSH may control gene expression and the activity of proteins through glutathionylation and thiol-disulfide conversion. This review discusses the size and redox state of the GSH pool, including their regulation, their role in redox signalling and defense processes, and the changes caused by abiotic stress.     

植物热激蛋白与作物非生物抗逆性的改良

文章就植物热激蛋白(Hsps)的种类、产生、生物学功能及其在作物抗逆性改良中的研究进展作介绍。     

Trehalose: A Key Organic Osmolyte Effectively Involved in Plant Abiotic Stress Tolerance

Trehalose is a natural non-reducing sugar that is found in the vast majority of organisms such as bacteria, yeasts, invertebrates and even in plants. Regarding its features, it is considered as a unique compound. It plays a key role as a carbon source in lower organisms and as an osmoprotectant or a stabilizing molecule in higher animals and plants. Although in plants it is present in a minor quantity, its levels rise upon exposure to abiotic stresses. Trehalose is believed to play a protective role against different abiotic stressful cues such as temperature extremes, salinity, desiccation. Moreover, it regulates water use efficiency and stomatal movement in most plants. Detectable endogenous trehalose levels are vital for sustaining growth under stressful cues. Exogenously applied trehalose in low amounts mitigates physiological and biochemical disorders induced by various abiotic stresses, delays leaf abscission and stimulates flowering in crops. External application of trehalose also up-regulates the stress responsive genes in plants exposed to environmental cues. The genetically modified plants with trehalose biosynthesis genes exhibit improved tolerance against stressful conditions. An increased level of trehalose has been observed in transgenic plants over-expressing genes of microbial trehalose biosynthesis. However, these transgenic plants display enhanced tolerance to heat, cold, salinity, and drought tolerance. Due to multiple bio-functions of this sugar, it has gained considerable ground in various fields. However, exogenous use of this bio-safe sugar would only be possible under field conditions upon adopting strategies of low-cost production of trehalose. In short, trehalose is a unique chemical that preserves vitality of plant life under harsh ecological conditions. Certainly, the new findings of this disaccharide will revolutionize a wide array of new avenues.

     

植物抗非生物胁迫microRNA研究进展

非生物胁迫是导致全球作物减产的重要因素,在植物应对非生物胁迫的生命反应中,编码蛋白的基因起到了非常重要的作用。随着研究的不断深入,发现microRNA(miRNA)在植物抗非生物胁迫中发挥着非常重要的作用。microRNA是一类非编码的RNA,长度约22~24 nt,通过作用于靶基因的mRNA进行调控。miRNA可以在植物应对多种非生物胁迫中发挥作用,如过氧化、营养缺乏、盐碱、干旱及其他机械胁迫等。我们基于目前的研究进展,着重介绍了miRNA的生物合成、作用机制,及其在多种非生物胁迫中的作用。     

植物microRNAs在植物发育和非生物胁迫响应中的作用

microRNAs(miRNAs)是一类内源的长度约为22个核苷酸的非编码小分子RNA,其通过对靶基因mRNA进行切割或翻译抑制调节mRNA的表达,在植物中起到重要的作用.主要介绍了植物miRNAs的特征、合成和作用机制,综述了miRNAs在植物生长发育和非生物胁迫响应中的作用.     

Roles of Nitric Oxide in Conferring Multiple Abiotic Stress Tolerance in Plants and Crosstalk with Other Plant Growth Regulators

Journal of Plant Growth Regulation - Nitric oxide (NO) is a free-radical gasotransmitter signaling molecule associated with a varied spectrum of signal transduction pathways linked to inducing...     

Role of Glutathione Peroxidases and Peroxiredoxins in Free Radical-Induced Pathologies

Biochemistry (Moscow) - In this review, we discuss the pathogenesis of some socially significant diseases associated with the development of oxidative stress, such as atherosclerosis, diabetes, and...     

脯氨酸在植物非生物胁迫耐性形成中的作用

植物作为固着生活的有机体,经常暴露在多变且对其生长发育不利的环境条件中,这些生物或非生物的胁迫因子严重影响着植物的生长、发育、生存和分布。脯氨酸在植物抵抗逆境胁迫过程中起着重要的作用。根据国内外的最新研究进展,结合我们的研究成果,对植物体内脯氨酸的代谢途径、渗透调节、抗氧化、分子伴侣、生长发育信号和毒性等方面进行了综述,并对该研究领域作了展望。     

水杨酸与植物抗非生物胁迫

本文综述了水杨酸在诱导植物抗（耐）非生物胁迫如重金属、自氧、紫外辐射、过冷、热激、水分亏缺和盐胁迫等方面的进展,并探讨了水杨酸作用的分子、生理机制。     

Plant Rabs: Characterization,Functional Diversity,and Role in Stress Tolerance

Rab proteins form the largest family of small guanosine triphosphate (GTP)-binding proteins. The Rab family in plants is divided into eight subfamilies, Rab1, Rab2, Rab5, Rab6, Rab7, Rab8, Rab11, and Rab18. Phylogenetic analyses of amino acid sequence of Rab GTPases suggest their segregation into subfamilies on the basis of their localization and/or function in membrane trafficking. The Rab GTPases are localized to the cytosolic face of specific intracellular membranes, where they function as regulators of distinct steps in membrane-trafficking pathways. The Rab proteins show highly conserved structural features with a great functional versatility. They play an important role in regulating hormone signaling during fruit ripening and apical dominance, brassinosteroid biosynthesis, pollen and nodule development, and in response to both abiotic and biotic stresses.     

植物耐热性及热激信号转导机制研究进展

随着温室效应的加剧,全球气候变暖已经成为现代农业生产体系所面临的严峻挑战．高温灾害性气候是影响作物产量的一种主要的非生物胁迫．因此,对于农作物生产而言,研究植物耐热信号转导机制不仅有重要的科学意义,而且有现实的紧迫性．最近几年,在阐明植物耐热信号转导机制的研究方面取得了很多重要的进展,这些进展涵盖植物高温胁迫的感受机制、热激转录因子和热激蛋白的表达调控、热激转录因子结合蛋白参与耐热性调控的分子机制等几个主要的方面．热胁迫影响细胞膜系统、RNA、蛋白质的稳定性,同时改变酶的活性和细胞骨架系统．当热胁迫来临时,植物的转录组会发生显著变化,所涉及的基因大约占基因组的2％．这些高温胁迫响应基因构成了热激响应网络,是植物抵御热胁迫的第一道防线．植物的耐热性分为基础耐热性和获得性耐热性．基础耐热性是植物固有的耐热性．获得性耐热性是温和的热驯化诱导的耐热性．获得性耐热性状的形成反映了植物在自然生长环境下适应高温胁迫的生理机制．     

Induction of Abiotic Stress Tolerance by Salicylic Acid Signaling

The role of salicylic acid (SA) as a key molecule in the signal transduction pathway of biotic stress responses has already been well described. Recent studies indicate that it also participates in the signaling of abiotic stresses. The application of exogenous SA could provide protection against several types of stresses such as high or low temperature, heavy metals, and so on. Although SA may also cause oxidative stress to plants, partially through the accumulation of hydrogen peroxide, the results published so far show that the preliminary treatment of plants with low concentrations of SA might have an acclimation-like effect, causing enhanced tolerance toward most kinds of abiotic stresses due primarily to enhanced antioxidative capacity. The effect of exogenous SA depends on numerous factors such as the species and developmental stage of the plant, the mode of application, and the concentration of SA and its endogenous level in the given plant. Recent results show that not only does exogenous SA application moderate stress effects, but abiotic stress factors may also alter the endogenous SA levels in the plant cells. This review compares the roles of SA during different abiotic stresses.     

LTP在植物抗环境胁迫中的作用

脂质转移蛋(白Lipid transfer protein,LTP)是一类分泌蛋白,曾被认为是一种在体外膜间进行脂质转移的蛋白,因其作用对象很广泛,所以目前又称其为非特异性LTP(non-specific lipid transfer proteins,nsLTPs)。有很多证据表明nsLTPs可能参与多方面的植物细胞与生理生化反应,这些生物学功能包括:参与角质层的合成和胚胎的发育;适应各种胁迫环境;抗病原微生物等作用,尤其是在适应胁迫环境中,起到很大作用。介绍了nsLTPs在植物抗环境胁迫中所发挥的作用,同时对应用研究作了简单展望。