Plant salt tolerance and Na^+ sensing and transport

Salinity is a global challenge to agricultural production. Understanding Na^+ sensing and transport in plants under salt stress will be of benefit for breeding robustly salt-tolerant crop species. In this review, first, possible salt stress sensor candidates and the root meristem zone as a tissue harboring salt stress-sensing components are proposed. Then,the importance of Na^+ exclusion and vacuolar Na^+ sequestration in plant overall salt tolerance is highlighted. Other Na^+ regulation processes, including xylem Na^+ loading and unloading, phloem Na^+ recirculation, and Na^+ secretion, are discussed and summarized.Along with a summary of Na^+ transporters and channels, the molecular regulation of Na^+ transporters and channels in response to salt stress is discussed. Finally, some largely neglected issues in plant salt stress tolerance, including Na^+ concentration in cytosol and the role of Na^+ as a nutrient, are reviewed and discussed.

Advanced Backcross QTL Analysis for the Whole Plant Growth Duration Salt Tolerance in Rice(Oryza sativa L.)

Salinity is a major factor limiting rice yield in coastal areas of Asia. To facilitate breeding salt tolerant rice varieties, the wholeplant growth duration salt tolerance（ST） was genetically dissected by phenotyping two sets of BC2F5 introgression lines（ILs） for four yield traits under severe natural salt stress and non-stress filed conditions using SSR markers and the methods of advanced backcross QTL（AB-QTL） analysis and selective introgression. Many QTLs affecting four yield traits under salt stress and nonstress conditions were identified, most（〉90%） of which were clustered in 13 genomic regions of the rice genome and involved in complex epistasis. Most QTLs affecting yield traits were differentially expressed under salt stress and non-stress conditions. Our results suggested that genetics complementarily provides an adequate explanation for the hidden genetic diversity for ST observed in both IL populations. Some promising Huanghuazhan（HHZ） ILs with favorable donor alleles at multiple QTLs and significantly improved yield traits under salt stress and non-stress conditions were identified, providing excellent materials and relevant genetic information for improving rice ST by marker-assisted selection（MAS） or genome selection.

Genetic Engineering Peanut for Higher Drought- and Salt-Tolerance

Peanut (Arachis hypogaea L.) is one of the major oilseed crops, mainly grown in tropical and sub-tropical regions of the world. It is also rich in proteins, vitamins and ions, therefore it constitutes an important portion of food nutrition for people in these regions. The production of peanut is being threatened by the changing environments as the major peanut producing counties such as China, India, and USA are facing severe water shortage for peanut irrigation. The yield and quality of peanut are negatively affected by drought and salinity. Making peanut more droughtand salt-tolerant will likely sustain peanut production in countries where water shortage or saline soil are already problems. Efforts were made to genetically engineer peanut for higher tolerance to drought and salt. Analysis of these transgenic peanut plants indicated that the agronomic traits such as peanut yields were the same between wild-type and transgenic peanut plants under normal growth conditions, yet the yields of transgenic peanut plants were much higher than wild-type peanut plant under reduced irrigation conditions. Other traits such as protein content and fatty acid compositions in the seeds of transgenic peanut plants were not altered under both normal and drought conditions, indicating that the genetic manipulation of peanut for stress tolerance did not affect chemical compositions of peanut seeds in transgenic peanut plants, only increased seed yields under stress conditions.

Screening for Sodium-Salt Tolerance at the Seedling Stage of Rice(Oryza sativa L.)Genotypes from Sudan and South Sudan

Morpho-physiological and genetic studies of salinity are important in understanding the mechanism of plant adaptation to stressful environment.Eighteen rice genotypes collected from Sudan and South Sudan,which were never tested for salt tolerance,as well as two genotypes(FL478 as tolerant check and IR29 as sensitive check)from the International Rice Research Institute(IRRI),were subjected to salinity stress at seedling stage.Test was carried out in hydroponic system applying electrical conductivity(EC)12 dS/m NaCl using randomized complete block design with three replicates.Most of the genotypes showed sensitivity to salt stress;one genotype PIPANFARY RED2 was moderately sensitive and three genotypes MASURY1,MASURY2 and FL478 were tolerant.Salinity significantly reduced leaf dry weight,shoot dry weight,root dry weigh and biomass production(biomass/plant)by 31%,42%,60%and 47%,respectively.Tolerant genotypes accumulated low amount(2.52 g/100 g dry weight(dwt))of Na^+in the root,whereas highly sensitive genotypes accumulated high amount(3.87 g/100 g dwt)of Na^+.Tolerant genotypes showed less reduction in K^+concentration than the sensitive genotypes.Therefore,they maintained lowest Na^+/K^+ratio in the shoot(1.47%)than in the root(3.69%)compared to the intolerant genotypes(7.49%and 8.49%).The genotypes that showed tolerance to salinity stress can be used as a source of resistance/tolerance in a breeding program for rice improvement in uplands areas in semi-arid condition.

Overexpression of SOS Genes Enhanced Salt Tolerance in Sweetpotato

The production of transgenic sweetpotato （cv.Xushu 18） plants exhibiting enhanced salt tolerance using salt overly sensitive （SOS） genes was achieved through Agrobacterium tumefaciens-mediated transformation.A.tumefaciens strain EHA105 harbors a binary vector pCAMBIA3301 with SOS genes （SOS1,SOS2 and SOS3） and bar gene.Selection culture was conducted using 0.3 mg L^-1 phosphinothricin （PPT）.A total of 40 plants were produced from the inoculated 170 cell aggregates via somatic embryogenesis.PCR analysis showed that 37 of the 40 regenerated plants were transgenic plants.The in vitro assay demonstrated that superoxide dismutase （SOD） and proline were significantly more accumulated and malonaldehyde （MDA） was significantly less accumulated in 21 transgenic plants than in control plants when they were exposed to 86 mmol L^-1 NaCl.Salt tolerance of these 21 plants was further evaluated with Hoagland solution containing 0,51,86,and 120 mmol L^-1 NaCl in the greenhouse.The results indicated that 6 of them had significantly better growth and rooting ability than the remaining 15 transgenic plants and control plants.Expression of SOS genes in the 6 salt-tolerant transgenic plants was demonstrated by RT-PCR analysis.This study provides an alternative approach for improving salt tolerance of sweetpotato.

特基拉芽孢杆菌Bt-RS对盐胁迫环境下香蕉幼苗生长的影响

土壤盐渍化是世界性生态环境问题,是阻碍作物生长并致使农业生产损失的潜在非生物胁迫因子之一。利用植物根际促生菌促进植物生长,提高植物耐盐性,缓解植物所受的非生物胁迫被视为1种新兴有效可行方法。本研究以实验室前期于南海岛礁根际土壤中分离到的1株特基拉芽孢杆菌(Bacillus tequilensis)Bt-RS为研究对象,利用功能培养基对其耐盐特性和耐盐促生性状进行定性定量分析,并进一步通过土壤盆栽实验评价该菌株在盐胁迫环境下对香蕉幼苗生长的影响。研究结果显示:Bt-RS菌株能够在NaCl含量为0~10%的条件下生长,能耐受多种类型盐分,具有产1-氨基环丙烷-1-羧酸(1-aminocyclopropane-1-carboxylate,ACC)脱氨酶能力;在1%~5%的NaCl浓度下能够分泌植物生长素吲哚-3-乙酸(indole-3-acetic acid,IAA),最大产量值为6.4mg/L。盆栽实验结果显示:在正常条件下,接种菌株Bt-RS的香蕉幼苗相比未接种菌株其株高、叶面积、地上部分鲜重、地下部分鲜重、地上部分干重、地下部分干重分别提高40.30%、93.00%、102.38%、81.08%、65.82%、50.50%;在200mmol/L盐胁迫环境下,接种菌株Bt-RS的香蕉幼苗与对照组相比在株高、叶面积、地上部分鲜重、地下部分鲜重、地上部分干重、地下部分干重方面分别提高20.55%、65.01%、98.14%、144.93%、87.85%、54.01%;在正常条件与盐胁迫下接种菌株均能显著提高香蕉幼苗的株高、叶面积以及生物量(P<0.05),盐胁迫环境下的实验组与正常条件下的对照组相比在株高和叶面积上均无显著差异,因此通过施用菌株Bt-RS能够有效缓解NaCl对香蕉幼苗的胁迫,促进香蕉幼苗的生长。综上结果表明,特基拉芽孢杆菌Bt-RS具有较强的耐盐性以及产IAA和ACC能力,能够促进香蕉幼苗生长并在盐胁迫环境下显著提高植物耐盐性,可为开发与利用盐渍土提供菌株资源。

1-磷酸甘露醇脱氢酶基因转化水稻的研究

PCR和 Southern blotting检测表明 ,来自大肠杆菌的 mtl D基因已通过农杆菌介导整合进水稻基因组。mtl D基因在 T1代出现分离 ,T2 代出现纯系。在 0 .75% Na Cl胁迫下 ,7个转基因 T3 代株系都能检测到 mtl D酶活性 ,与对照相比细胞膜的相对电导率和大分子渗漏值明显降低。部分转基因株系能在 1 .0 % Na Cl浓度下正常生长 ,而对照在 0 .5% Na Cl浓度下已不能存活。通过有性杂交途径实现了 mtl D和 gut D两个基因的聚合 ,部分杂交后代株系能在 1 .2 5% Na Cl胁迫下正常生长结实。

细菌mtl-D基因的克隆及在转基因八里庄杨中的表达

运用ＰＣＲ方法克隆了大肠杆菌１－磷酸甘露醇脱氢酶（ｍｔｌ－Ｄ）基因，序列分析表明与已发表序列相比，除第 ４１６位密码子由 ＡＡＡ代替 ＣＡＴ、相应的氨基酸由 Ｌｙｓ代替 Ｈｉｓ外，其他部分均相同。该基因插入植物双元载体中，经土壤农杆菌介导导入八里庄杨［１］，经卡那霉素筛选后再经盐胁迫筛选获得一批较高耐盐性的转化植株，在附加 ０.６％ＮａＣｌ的培养基中生长良好，而对照在附加 ０．４％ ＮａＣｌ的培养基中不能存活。对转化植株进行的 ＰＣＲ检测、Ｎｏｒｔｈｅｒｎ杂交，说明外源基因已整合到染色体上并且有转录。

植物色素在24-表油菜素内酯调节油菜耐盐性中的作用(英文)

为了探索24-表油菜素内酯(24-EBL)对盐胁迫下油菜生长的调节效应和植物色素在油菜耐盐性中的作用,采用盆栽实验,在盐胁迫下外源喷施1 000、10、0.1、0.001nmol.L-1 24-EBL处理油菜幼苗,测定植株的生物量、电解质渗漏率(ELP)、净光合速率(Pn)、光合色素、酚类、类黄酮、花青素含量以及抗氧化能力(T-AOC)。结果显示:(1)24-EBL可显著缓解盐胁迫对油菜幼苗的氧化伤害,提高盐渍下油菜幼苗Pn和光合色素含量,并以0.1nmol.L-1 24-EBL(EBL3)对生长的调控效应最佳。(2)盐胁迫下,植株不同部位叶片的β-胡萝卜素(β-Car)和叶黄素(Lut)含量均显著下降,EBL3处理可显著提高其上部叶的β-Car含量,以及上部和中部叶的Lut含量;EBL3处理可显著提高盐胁迫下油菜所有叶片和叶柄的酚类含量,以及叶柄中类黄酮含量;EBL3处理可显著提高盐胁迫下油菜幼苗所有器官的花青素含量。(3)EBL3仅能够诱导上部叶和中部叶类胡萝卜素(Car)提取液的抗氧化能力(T-AOC)提高,但可诱导植株所有器官的酚类提取液的T-AOC提高。(4)不同部位的叶片Car、β-Car和Lut含量均与其Car提取液的T-AOC呈极显著正相关;而上部叶的总酚和花青素含量、中部叶和叶柄的花青素含量及茎秆中总酚、类黄酮和花青素含量与各自的酚类提取液的T-AOC呈极显著正相关。研究表明,外源喷施适宜浓度的24-EBL能够显著促进盐渍条件下油菜幼苗的光合能力,提高其抗氧化能力,从而增强其对盐渍胁迫的适应性,而光合色素和花青素水平被24-EBL诱导上升在油菜幼苗抗氧化过程中起着重要的作用。

Transformation of the salttolerant gene of Avicennia marina into tobacco plants and cultivation of salt-tolerant lines

Salt-tolerant gene, CSRG1, which was isolated from a kind of salt-tolerant mangroves, Avicennia marina, constructed the transgenic plasmid, pGAM189/CSRG1. CSRG1, GUS, Kmr and Hyg^r could be transferred into tobacco genome by the ameliorated leaf discs method of agro-bacterium-mediate transformation. Thirteen stable resistant lines were obtained when fifty transgenic explants were selected through 50 mg/L hygromycin and 150 mg/L kanamycin. Assessments of PCR amplification, Southern blot analysis and GUS histochemical staining showed that CSRG1 has been integrated into the genome of the eleven transgenic lines (frequency of transformation was 22%). Northern bolt analysis revealed that CSRG1 had expressed in transgenic lines. The assessments of salt-tolerant ability and photosyn-thetic rates indicated that the survival rate of the transgenic lines is 80%—90% and the transgenic lines could increase by 30%—40% in plant height, even when they were cultivated in MS medium containing 2% NaCl and the total seawater (salinity 24). It is supposed that the special physiologic metabolic pathway formed by the products of CSRG1 can really endow the tobacco plants with the high salt-tolerant ability, not only to Na^+ stress, but also to the comprehensive stress of various ions.

Insights into plant salt stress signaling and tolerance

Soil salinization is an essential environmental stressor,threatening agricultural yield and ecological security worldwide.Saline soils accumulate excessive soluble salts which are detrimental to most plants by limiting plant growth and productivity.It is of great necessity for plants to efficiently deal with the adverse effects caused by salt stress for survival and successful reproduction.Multiple determinants of salt tolerance have been identified in plants,and the cellular and physiological mechanisms of plant salt response and adaption have been intensely characterized.Plants respond to salt stress signals and rapidly initiate signaling pathways to re-establish cellular homeostasis with adjusted growth and cellular metabolism.This review summarizes the advances in salt stress perception,signaling,and response in plants.A better under-standing of plant salt resistance will contribute to improving crop performance under saline conditions using multiple engineering approaches.The rhizosphere microbiome-mediated plant salt tolerance as well as chemical priming for enhanced plant salt resistance are also discussed in this review.

ST6-40转基因棉花株系的获得与耐盐性鉴定

棉花是世界上重要的经济作物之一,然而棉花的产量和品质经常受到盐害胁迫的影响,利用基因工程技术研发耐盐棉花品种,是解决这个问题的有效方法。ST6-40基因是通过一种功能基因挖掘方法从小盐芥中分离得到,该方法基于构建大量独立株系组成的转基因种子文库,通过高通量遗传筛选法筛选耐盐株系,得到的基因与耐盐功能直接相关。将携带有ST6-40基因的pCB2004-ST6-40重组载体通过农杆菌介导法转入陆地棉品种R15,获得转基因棉花再生株系;采用棉花生理指标测定法和直接耐盐鉴定方法对获得的转基因棉花株系进行耐盐性鉴定,转基因棉花株系T1和T2通过测定叶片游离脯氨酸含量进行鉴定,转基因棉花株系T_(3)采用盐水浇灌直接鉴定,依据盐害级数计算盐害指数进行耐盐性判定。结果表明,共进行了350个转化事件,转化率为19%,获得65个阳性T_(0)株系,其中再生植株中90%为阳性苗;经T_(1)、T_(2)、T_(3)连续3代基因组水平PCR检测及RNA水平上表达量鉴定,表明目的基因能够稳定遗传。转基因阳性植株经T_(1)、T_(2)、T_(3)耐盐性检测,获得6个耐盐性较受体对照R15显著增强的转基因纯合株系,4个转基因株系耐盐性优于耐盐对照品种中99807,表明转入ST6-40基因能有效提高棉花品种的耐盐性。

滨海盐碱湿地景观建设的基本原则--以天津光合谷湿地公园为例

滨海盐碱湿地的利用已成为近年来沿海城市生态建设的重要组成部分,但是由于在开发利用过程中没有重视其特有的立地条件,未能进行科学合理的景观设计和针对性的盐碱地植被构建,导致在景观建设过程中造成了巨大损失。本文分析了天津光合谷湿地公园前期景观建设失败的原因,探讨了滨海盐碱湿地景观建设的3条基本原则,即排盐和控盐是关键、改良土壤是基础、植物选择是重点。只有盐、土、植物的系统性、针对性设计才能建造可持续的滨海盐碱湿地公园。

海水养殖尾水人工湿地处理系统及其脱氮过程研究进展和展望

利用人工湿地处理海水养殖尾水具有很大的应用前景,其中,脱氮是人工湿地的主要任务之一。基质上栽培的植物和附着的微生物参与的氮循环是人工湿地生物脱氮的主要路径,植物和多种氮代谢菌群在人工湿地内部相互协同与制约,构成了一个复杂的氮代谢网络。海水养殖尾水的高盐度和低碳氮比(C/N)又决定了此类人工湿地独特的处理环境和生物脱氮机制。同时,人工湿地的供氧模式、水力负荷(HRT)、水力停留时间(HLR)等水力条件参数对脱氮效能也有很大影响,对这些指标进行调控和优化,可以提高湿地的整体脱氮性能。本文从海水人工湿地的构建、基质的选取、耐盐植物的筛选、氮循环相关微生物以及运行参数调控四个方面,对近年来海水养殖尾水人工湿地生物脱氮方面的研究进展进行了综述和展望,以期为深入理解海水人工湿地脱氮机制和优化运行方式提供参考。

利用盐生植物发展“盐湖农业”研究进展

由于人口增长和全球气候变暖,次生土壤盐碱化日趋严重,淡水资源缺乏,使得人类粮食和食品供给面临严峻挑战。“盐湖农业”为解决这一问题提供了一种新的思路。本文评述了盐生植物在农业上的应用国内外研究进展,重点综述了盐生植物作为食物、饲料、工业原料等方面的研究。盐生植物生长环境比较恶劣,一些盐生植物为应对逆境环境而合成出丰富的次生代谢物,这些代谢物对预防疾病和促进健康大有益处,因此近年来市场对盐生植物的需求显著增加。我国盐湖资源丰富,利用盐生植物发展盐湖农业有得天独厚的条件,具有广阔的应用前景,本文最后提出了在我国发展盐湖农业的几点建议。

山东省黄河三角洲水生耐盐药用植物资源调查与分析

对山东省黄河三角洲地区水生耐盐药用植物的种类、生活型及对应药材入药部位、药性、功效进行统计调查分析。共调查到野生水生耐盐药用植物299种。根据恩格勒分类系统,这些植物隶属于76科204属;生活型以草本型为主,共222种。以299种药用植物为基源的药材共338种,其中全草入药药材144种,占药材种类数的42.60%;平性药材最多,共85种;苦味药、甘味药和辛味药数量较其他药味具有明显优势;以功效分类,清热药、利水渗湿类、活血化瘀类、化痰止咳类、止血药和补虚药占优势。针对水生耐盐药用植物特点,结合该区域自然状况,提出了合理开发和综合利用的建议。

植物耐盐机制研究进展及展望

植物的生长和生产面临各种生物和非生物胁迫,其中盐胁迫严重影响植物的正常生长发育、品质和产量形成。植物在长期的演化过程中,进化出了适应盐胁迫的形态结构、生理生化反应和遗传基础。在形态结构上,耐盐植物的叶片具有蜡质层、气孔密度低于盐敏感植物,另外具有泌盐或者阻断功能的盐腺、毛状体、盐囊泡、凯氏带等结构;在生理活动调节方面,一方面耐盐植物具有高的酶促和非酶促抗氧化物质,如SOD、CAT、酚类物质等,另一方面耐盐植物具有较高的渗透调节物质含量,或者在盐胁迫下可以合成渗透调节物质,包括有机物质可溶性蛋白和糖以及无机盐离子等;在分子机理方面,SOS途径是研究得最为清晰的离子调控途径,通过SOS1、SOS2和SOS3协同作用维持细胞内Na^(+)/K^(+)平衡;此外,植物激素及碳代谢途径在植物耐盐过程中亦具有重要作用。本研究通过综述植物耐盐研究进展,探讨耐盐植物在形态结构、生理基础、遗传分子基础和转基因手段在响应盐胁迫的潜在研究重点和方向,有助于研究人员快速找到切入点,逐步完善植物的耐盐机理体系,加快耐盐植物的高效利用。

油菜素内酯调控植物耐盐机理研究进展

油菜素内酯(brassinosteroid,BR)作为新型、高效的植物激素,广泛参与植物的各种生理过程,可以缓解多种非生物胁迫。阐述了BR处理缓解盐胁迫的生物学功能,总结了拟南芥、农作物水稻以及多种园艺植物的BR信号通路,并通过介绍BR的耐盐机理,进一步分析了植物遭受盐胁迫时的应答信号转导通路,旨在为加强BR在提高植物耐盐方面的应用提供理论依据。

耐盐促生菌提高盐胁迫下植物生长的研究进展

土壤盐渍化是全世界面临的环境难题之一,严重影响作物的生长发育。而施用耐盐促生菌能够快速、高效提高植物的生长量,改善盐渍土壤的性质。介绍了耐盐促生菌的种类,从其促生机制、提高植物耐盐机制的角度出发,阐述了盐胁迫下耐盐促生菌在不同植物中的应用。今后还需加强对耐盐促生菌的筛选、载体固定化以及与土著微生物的相互作用机制方面的研究,以期为耐盐促生菌进一步的大规模使用提供参考。

AMF和PGPR单独或“跨界”互作促进植物耐盐性的研究进展

盐碱地改良和利用对拓展我国后备耕地资源及保障国家粮食安全具有重要意义。根际微生物作为植物的“第二基因组”,在提高作物抗盐碱胁迫能力,促进作物“以种适地”方面具有巨大潜力。其中,丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)和植物根际促生细菌(plant growth promoting rhizobacteria,PGPR)均为重要的根际有益微生物,能显著提高植物耐盐性。本文分别总结了AMF和PGPR提高植物抗盐能力的相关研究进展,并进一步梳理了两者协同提高植物耐盐的机制,包括提高养分效率、调节激素内稳态、提高植物诱导抗性以及调控转录因子表达等,最后提出了基于两者跨界组合的改良方向。旨在充分理解盐胁迫条件下微生物耐盐促生的作用机制,为充分挖掘微生物资源潜力和发展生物技术治理盐碱地提供重要的科学支撑。