Overexpression of Multiple Dehydrin Genes Enhances Tolerance to Freezing Stress in Arabidopsis

To elucidate the contribution of dehydrins (DHNs) to freezing stress tolerance in Arabidopsis, transgenic plants overexpressing multiple DHN genes were generated. Chimeric double constructs for expression of RAB18 and COR47 (pTP9) or LTI29 and LTI30 (pTP10) were made by fusing the coding sequences of the respective DHN genes to the cauliflower mosaic virus 35S promoter. Overexpression of the chimeric genes in Arabidopsis resulted in accumulation of the corresponding dehydrins to levels similar or higher than in cold-acclimated wild-type plants. Transgenic plants exhibited lower LT50 values and improved survival when exposed to freezing stress compared to the control plants. Post-embedding immuno electron microscopy of high-pressure frozen, freeze-substituted samples revealed partial intracellular translocation from cytosol to the vicinity of the membranes of the acidic dehydrin LTI29 during cold acclimation in transgenic plants. This study provides evidence that dehydrins contribute to freezing stress tolerance in plants and suggests that this could be partly due to their protective effect on membranes.     

植物耐盐相关基因：SOS基因家族研究进展

土壤盐渍化是影响农业生产和生态环境的一个非常重要的非生物胁迫因素,也是现代生物科学迫切需要解决的问题。利用拟南芥研究植物耐盐相关基因成为该领域的研究热点。几年来,该领域研究成果斐然。本文就SOS基因家族的三个耐盐基因SOS1、SOS2和SOS3的克隆、功能及相互关系作一概要的评述。 Abstract:The soil salination is a significant abiotic stress for agricultural production and ecological environment. The research on salt tolerance represents an important part for basic plant biology. Genetic analysis of salt tolerance genes in Arabidopsis has become a central issue in this research areas. In recent years, efforts from some laboratories in the world have led to some significant progresses in this field. In this paper, we will review the progress in salt tolerance genes SOS(salt overly sensitive):SOS1,SOS2 and SOS3.     

微丝骨架通过调控线粒体膜透性影响拟南芥耐盐性

植物微丝参与了许多重要的细胞生理活动,与植物耐盐性有密切的联系。在微丝解聚剂Latrunculin B（LatB）存在的情况下,拟南芥会表现出盐胁迫敏感。本研究结果表明盐胁迫下LatB可增加拟南芥线粒体膜通透性转换孔（mitochondrial permeability transition pore,MPTP）开放度,导致线粒体膜电势下降和细胞色素C的释放。而加入MPTP抑制剂环孢素A（CsA）后,膜电势下降程度降低,细胞色素C释放减少,解聚微丝造成的盐敏感表型得到一定程度恢复。     

大豆耐盐机理及相关基因分子标记

大豆耐盐涉及多种生理代谢途径.耐盐大豆能够通过Cl-排除、控制Na 的吸收和转运、合成渗透调节物质、改变细胞膜膜脂组分及相关酶类的活性等多种形式来适应盐胁迫;野生大豆群体具有盐腺,从形态结构上适应盐逆境;大豆-根瘤菌共生体在盐胁迫下通过互作来提高整体的耐盐性.分子生物学技术应用于大豆耐盐研究,已获得了一些与耐盐相关基因连锁的分子标记.广泛搜集筛选大豆栽培种和野生种资源,利用分子生物学技术和基因工程提高大豆耐盐性,将成为未来大豆耐盐研究的主要内容.     

大豆耐盐机理及相关基因分子标记

大豆耐盐涉及多种生理代谢途径。耐盐大豆能够通过Cl-排除、控制Na+的吸收和转运、合成渗透调节物质、改变细胞膜膜脂组分及相关酶类的活性等多种形式来适应盐胁迫;野生大豆群体具有盐腺,从形态结构上适应盐逆境;大豆-根瘤菌共生体在盐胁迫下通过互作来提高整体的耐盐性。分子生物学技术应用于大豆耐盐研究,已获得了一些与耐盐相关基因连锁的分子标记。广泛搜集筛选大豆栽培种和野生种资源,利用分子生物学技术和基因工程提高大豆耐盐性,将成为未来大豆耐盐研究的主要内容。     

Wheat V-H+-ATPase Subunit Genes Significantly Affect Salt Tolerance in Arabidopsis thaliana

Genes for V-H⁺-ATPase subunits were identified and cloned from the salt-tolerant wheat mutant RH8706-49. Sequences of these genes are highly conserved in plants. Overexpression of these genes in Arabidopsis thaliana improved its salt tolerance, and increased the activities of V-H⁺-ATPase and Na⁺/H⁺ exchange, with the largest increase in plants carrying the c subunit of V-H⁺-ATPase. Results from quantitative RT-PCR analysis indicated that the mRNA level of each V-H⁺-ATPase subunit in the Arabidopsis increased under salt stress. Overall, our results suggest that each V-H⁺-ATPase subunit plays a key role in enhancing salt tolerance in plants.     

Development of a Human Antibody Cocktail that Deploys Multiple Functions to Confer Pan-Ebolavirus Protection

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拟南芥AtUNE12基因的耐盐功能初探

bHLH转录因子家族成员在植物生长发育、生理代谢及非生物胁迫响应过程中起重要作用。本研究选取拟南芥抗逆相关bHLH转录因子家族中AtUNE12基因为研究对象,对其进行耐盐功能初探。首先构建AtUNE12基因的植物过表达载体（pROKⅡ-AtUNE12）,通过农杆菌介导的浸花法转化拟南芥,利用qRT-PCR技术检测获得T₃代AtUNE12过表达转基因植株。在盐胁迫下,分析过表达AtUNE12与野生型拟南芥长势、根长及鲜重;比较过表达AtUNE12与野生型植株的电解质渗透率、失水率、MDA含量、POD与SOD活性及H₂O₂含量,鉴定AtUNE12基因是否具有耐盐能力。结果表明：过表达AtUNE12基因降低了拟南芥植株的失水率、电解质渗透率及MDA含量,保护细胞膜结构的完整性;增强了POD与SOD活性,降低了拟南芥植株内的H₂O₂含量,进而增强拟南芥植株的ROS清除能力,从而提高拟南芥的耐盐能力。     

过量表达大叶补血草LgNHX1基因对拟南芥耐盐性的影响

利用植物表达载体pCAMBIA1301和农杆菌GV3101将LgNHX1(全长1 656 bp)基因在拟南芥中过量表达.在含30 mg/L潮霉素的培养基上筛选获得LgNHX1的纯合转化子,并对其进行了分子鉴定和耐盐性分析.结果显示,经PCR和RT-PCR鉴定,野生型植株(对照)没有出现扩增条带,而转基因株系有相应的扩增条带,表明LgNHX1的确已经整合到拟南芥的基因组中,并已正常转录.在不同盐浓度处理下,转基因株系生长情况好于野生型对照;转基因植株地上部分和根的干重、鲜重相对高于野生型对照,但差异没有达到显著水平;当盐浓度达到150-200 mmol/L时,两个特基因株系的Na+含量显著高于野生型,K+含量极显著高于野生型.以上结果表明,过量表达LgNHX1基因可能增强了拟南芥将Na+区隔化至液泡的能力,提高了转基因拟南芥的耐盐能力.     

Brassinosteroids Confer Tolerance to Salt Stress in Eucalyptus urophylla Plants Enhancing Homeostasis,Antioxidant Metabolism and Leaf Anatomy

Journal of Plant Growth Regulation - The sodium ion (Na+) is potentially toxic to plants because it can cause K+/Na+ imbalances, oxidative stress and negatively affect growth. Brassinosteroids...     

植物耐盐相关基因克隆与转化研究进展

土地盐渍化是农作物产量降低的一个重要因素。从盐分对植物的伤害、植物耐盐的机理、耐盐相关基因的克隆及转耐盐基因植物等方面论述了植物的耐盐机理及转耐盐基因植物的研究现状,分析了耐盐性状的复杂性,并对前景进行了展望。     

新疆短命植物小拟南芥耐盐性的初步研究

利用种子萌发及石蜡切片等方法对新疆短命植物小拟南芥(Arabidopsis pumila)在盐胁迫下种子的萌发率及植株生长发育的变化进行了研究,结果显示:(1)盐胁迫对小拟南芥种子萌发具有抑制作用,当去除盐分后,部分种子能够重新萌发.(2)盐分影响幼苗的形态及内部结构,低盐(50 mmol/L)时,幼苗基生叶较大且数量增加;叶中栅栏组织细胞大,排列舒展;根中导管数量明显增多,植株生长健壮而旺盛;而较高盐(150 mmol/L)时,叶片变小增厚,色深绿,底部叶变黄白色,叶中栅栏组织细胞窄小,排列紧密;根中导管数急剧下降,植株生长受到明显抑制.(3)盐胁迫对成株期植株的高度、花序轴长、角果数等性状都有显著影响,但在NaCl浓度达500 mmol/L时,植株仍然存活且有一定的结实率,显示此时的耐盐性比萌发期和幼苗期有显著提高.研究表明,小拟南芥从幼苗至成株期耐盐性逐渐增强,该特征与其对自然生存环境的适应相关.     

Increased Drought Tolerance through the Suppression of ESKMO1 Gene and Overexpression of CBF-Related Genes in Arabidopsis

Improved drought tolerance is always a highly desired trait for agricultural plants. Significantly increased drought tolerance in Arabidopsis thaliana (Columbia-0) has been achieved in our work through the suppression of ESKMO1 (ESK1) gene expression with small-interfering RNA (siRNA) and overexpression of CBF genes with constitutive gene expression. ESK1 has been identified as a gene linked to normal development of the plant vascular system, which is assumed directly related to plant drought response. By using siRNA that specifically targets ESK1, the gene expression has been reduced and drought tolerance of the plant has been enhanced dramatically in the work. However, the plant response to external abscisic acid application has not been changed. ICE1, CBF1, and CBF3 are genes involved in a well-characterized plant stress response pathway, overexpression of them in the plant has demonstrated capable to increase drought tolerance. By overexpression of these genes combining together with suppression of ESK1 gene, the significant increase of plant drought tolerance has been achieved in comparison to single gene manipulation, although the effect is not in an additive way. Accompanying the increase of drought tolerance via suppression of ESK1 gene expression, the negative effect has been observed in seeds yield of transgenic plants in normal watering conditions comparing with wide type plant.     

过量表达柳树两个SVP1s基因提高拟南芥抗盐胁迫能力

在拟南芥、水稻等草本植物中,人们对位于液泡膜上质子泵焦磷酸酶（VPase）进行了较为深入的研究,其通过水解焦磷酸释放的能量将H+从细胞质泵入液泡中,从而驱动Na+、K+等的运输,避免了细胞质中因过量的Na+、K+造成的伤害,保护了细胞的正常功能．但是木本植物如柳树中的VP1基因（SVP1)的功能尚未见报道．本研究检测了两个SVP1s同源基因在柳树L0911不同的组织（器官）中以及昼夜条件（以叶片为代表组织）下的表达模式,同时,分析了过量表达SVP1s拟南芥T3转基因株系的耐盐特性. 结果表明：SVP1.1在韧皮部中表达最高,而SVP1.2在韧皮部和新生枝条是其在根部的4～5倍;叶片中两个SVP1s在白天稳定表达,18∶00后逐渐下降,在黑暗条件下,随着暗处理时间的延长SVP1.2增幅较大;在盐胁迫条件下,SVP1s转基因拟南芥T3株系种子萌发率,叶片中与活性氧清除相关的酶,如SOD、POD和CAT等活性的诱导强度高于野生型对照;SVP1.1转基因株系叶片膜质氧化程度（MDA）低于野生型和35S:SVP1.2株系. 通过本研究显示,在拟南芥中过量表达柳树SVP1.1s提高了拟南芥的耐盐能力,揭示了木本植物中VP1基因同样具备保护细胞,使细胞耐受高盐胁迫的功能,同时也为选育优良耐盐树木品种提供了理论依据．     

Identification of Listeria monocytogenes Genes Involved in Salt and Alkaline-pH Tolerance

The capacity of Listeria monocytogenes to tolerate salt and alkaline stresses is of particular importance, as this pathogen is often exposed to such environments during food processing and food preservation. We screened a library of Tn917-lacZ insertional mutants in order to identify genes involved in salt and/or alkaline tolerance. We isolated six mutants sensitive to salt stress and 12 mutants sensitive to salt and alkaline stresses. The position of the insertion of the transposon was located in 15 of these mutants. In six mutants the transposon was inserted in intergenic regions, and in nine mutants it was inserted in genes. Most of the genes have unknown functions, but sequence comparisons indicated that they encode putative transporters.     

过表达水稻OsAQP增强转基因拟南芥耐盐性

水稻OsAQP是实验室前期从cDNA文库中筛选的功能未知的水通道蛋白质编码基因。本文采用DNA重组技术构建其植物过表达载体,并对拟南芥进行了遗传转化,筛选获得转基因拟南芥。采用50、100、125和150 mmol/L梯度盐胁迫处理,结果显示,转基因拟南芥的发芽率、根长以及鲜重分别比对照至少高17%、40.8%和14.29%,且差异达到显著水平（P<0.05）。在正常条件下,转基因植株叶片中抗坏血酸过氧化物酶(APX)活性显著高于WT;经300 mmol/L NaCl处理,转基因拟南芥叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、APX酶活性均升高,与处理前相比分别提高7.37倍、30.87倍和1.77倍,且与WT的酶活性差异达到显著水平（P<0.05）;丙二醛(MDA)含量也在处理后上升,但在转基因植株中的含量低于WT,分别是WT的0.74倍、0.68倍和0.62倍,差异同样达到显著水平（P<0.05）。本研究提示,OsAQP过表达不仅能够促进拟南芥种子萌发和根系生长,而且在盐胁迫下通过提高拟南芥内源抗氧化酶活性、降低膜脂过氧化程度,增强了转基因植株对一定程度盐胁迫的耐受性。