植物耐盐性研究进展

土壤现化是影响农业生产和生态环境的严重问题,耕地的减少和淡水资源的不足将迫使人类开发和利用大面积的盐碱地、海岸带和滩涂地带,植物耐盐的机理和耐盐植物的培育研究将成为研究的热点。本文就植物的耐盐性、植物中各种渗透调节剂及植物耐盐相关基因等这十年的研究进展作一概要的评价。     

植物耐盐性研究进展

土壤盐渍化是影响农业生产和生态环境的严重问题,耕地的减少和淡水资源的不足将迫使人类开发和利用大面积的盐碱地、海岸带和滩涂地带,植物耐盐的机理和耐盐植物的培育研究将成为研究的热点。本文就植物的耐盐性、植物中各种渗透调节剂及植物耐盐相关基因等方面近十年的研究进展作一概要的评价 。     

盐生植物耐盐性研究进展

盐胁迫是植物生长最重要的非生物胁迫之一.盐生植物具有耐盐性,可以在高盐环境下正常生长.通过对近年来有关盐生植物分类、盐渍化对植物的影响和耐盐机制等方面的研究进行梳理和分析,归纳总结了影响盐生植物耐盐性的各种因素,为更好地了解和开发利用盐生植物提供理论依据.     

耐盐性植物转基因工程的研究进展

随着分子生物学的迅速发展,已经发现了一系列与植物盐胁迫相关的基因。根据这些基因产物的作用,可以分为两大类:效应分子基因和调控分子基因。根据近年来采用基因工程方法提高植物耐盐性的策略和研究进展进行了概述,同时探讨了目前还存在的一些问题。     

质膜转运蛋白及其与植物耐盐性关系研究进展

植物细胞质膜有两种主要功能：⑴溶质运输（进出细胞）,溶质运输主要由转运蛋白完成;⑵信号传导,即接收信号并引发细胞生理生化响应。盐分过多对植物的伤害主要是离子毒害。质膜转运蛋白活性环境变化能做现迅速响应。本文简要叙述了植物细胞质膜转运蛋白类型、分子特性、生理功能及其活性调节。介绍了植物细胞质膜Ｈ＾＋－ＡＴＰａｓｅ、质膜氧化还原系统、质膜离子载体和离子通道对盐胁迫的响应及其这些响应与植物耐盐性之间的关     

质膜转运蛋白及其与植物耐盐性关系研究进展

植物细胞质膜有两种主要功能：(1)溶质运输(进出细胞),溶质运输主要由转运蛋白完成;(2)信号传导,即接收信号并引发细胞生理生化响应。盐分过多对植物的伤害主要是离子毒害。质膜转运蛋白活性对环境变化能做出迅速响应。本文简要叙述了植物细胞质膜转运蛋白类型、分子特性、生理功能及其活性调节。介绍了植物细胞质膜H+_ATPase、质膜氧化还原系统、质膜离子载体和离子通道对盐胁迫的响应及其这些响应与植物耐盐性之间的关系。     

植物同源多倍体耐盐性研究进展

多倍化是高等植物进化最重要的动力之一,多倍体植物由于基因组组成以及基因表达方面的变化,通常会表现出不同的生理现象,多倍体的抗性优于其同源二倍体祖先。土壤盐碱化和次生盐渍化是影响农作物生产的重要因素,严重制约着我国农业的可持续发展。同源多倍体植物耐盐能力较强,是作物遗传改良的重要种质资源,了解其耐盐机理对培育耐盐品种具有重要意义。本文从与盐胁迫相关的耐盐性进化、生理生化水平、细胞结构和分子层面等多角度总结了植物同源多倍体盐胁迫研究进展,并以作者所在研究团队培育出的多倍体西瓜为例讨论了多倍体抗逆性研究存在的问题及未来的发展方向,以期为多倍体抗逆优势机理研究提供参考。     

植物耐盐相关基因克隆的研究进展

随着植物分子生物学快速发展,植物耐盐性研究已深入到耐盐相关基因的克隆、基因的结构分析以及基因表达特性等领域.目前,耐盐相关基因的克隆工作进行的如火如荼,有很多植物的耐盐基因已经被克隆,这些已克隆的耐盐相关基因涉及盐胁迫信号传导、基因表达的调控因子、渗透调节物质、胚胎发育晚期丰富蛋白LEA(Late-embryogensiS-abundant)等,本文就盐胁迫涉及的信号传导基因、基因表达调控因子等的克隆研究进展作一简要概述.     

渗透胁迫调节的转基因表达对植物抗旱耐盐性的影响

干旱和盐渍是影响植物生长和农作物产量的最重要的环境因子,本文综述了近年来通过超量表达低分子量化合物和渗透肋迫保护蛋白等获得抗旱耐盐转基因植物的报道,旨在系统阐述转基因表达对植物抗旱耐盐性的影响。     

一氧化氮与植物耐盐性

盐胁迫是制约植物生长发育的主要环境因子之一,信号分子一氧化氮（NO）参与调节植物的耐盐性,本文介绍近年来NO合成及其与植物耐盐性关系的研究进展,并讨论了NO可能的作用机制。     

Construction and characterization of mutated LEA peptides in Escherichia coli to develop an efficient protein expression system

To develop an efficient protein expression system, we designed a late embryogenesis abundant (LEA) peptide by mutating the LEA peptide constructed in our previous study (LEA‐I). The peptide is based on the repeating units of an 11mer motif characteristic of LEA proteins from Polypedilum vanderplanki larvae. In the amino acid sequence of the 13mer LEA peptide, glycine at the 6th and 12th positions was replaced with other amino acids via point mutations. Glutamic acid, lysine, leucine, and asparagine in the LEA peptide at the 6th and 12th positions increased green fluorescence protein (GFP) expression. The GFP expression of the mutated LEA peptide was 1.5 to 2.0 times higher than that without LEA peptide. In contrast, the serine‐containing mutated LEA peptide has low GFP expression levels. We hypothesize that the position of amino acids and the nature of amino acid in LEA peptide are important for our coexpression system. These data suggest that the size, structure, and charge of amino acids in the LEA peptide improve the protection and expression of the target protein. The amino acid balance also plays an important role in the expression of the target protein.     

丹参DHN1基因的克隆与序列分析

丹参(Salvia miltiorrhiza Bge．)是一种重要的药用植物。以组织培养2～13w的丹参幼苗为材料,构建丹参cDNA库并进行大规模EST序列分析,所得序列经NCBI的BLAST工具分析,克隆号为rsmsxl-009377的序列与晚期胚胎丰富(Late Embryogenesis Abundant)基因家族Ⅱ中的成员有较高的同源性。根据其5’单向测序的结果设计引物“5'-GTGCGTAGACACATCGGTTC-3'”继续向3’测序,得到一个全长969bp的序列,序列分析发现该序列包含一个长690bp的开放阅读框(ORF),编码229个氨基酸,与NCBI注册的脱水素家族基因具有较高的同源性,且含有ⅡLEA蛋白的特征序列,表明本基因可能是一种新的脱水素基因,命名为DHN1,并住GENEBANK上进行了注册,序列号为：AY695932。     

棉花Lea蛋白D-113基因启动子的克隆及序列分析

为研究植物Lea(late embryogenesis abundant）蛋白基因启动子在种子中的特异性表达,通过PCR扩增,从棉花（Gossypium hirsutum cv.Coker312）中克隆了Lea蛋白基因家庭中D-113基因上游1024bp的调控序列。DNA序列分析结果表明,该片段与已报道的Lea蛋白基因同一家庭该基因的对应序列同源性达90%以上。将将启动子序列与GUS基因融合,构建成表达载体后,通过基因抢轰击导入到经ABA诱导处理的棉花胚性愈伤组织和油菜种子以及棉花的根、茎、叶中,组织化学分析结果表明,D-113基因启动子在胚中特异性表达。     

玉米胚胎发生后期丰富蛋白基因的启动子克隆与功能验证

该研究在生物信息学分析的基础上,克隆玉米胚胎发生后期丰富蛋白基因(MGL3)的启动子序列(pMGL3),进行非生物逆境应答元件分析以及实时定量PCR验证其非生物逆境胁迫响应特性,构建了pMGL3启动子驱动报告基因(GUS)表达载体,基因枪法转化玉米愈伤组织,通过GUS染色验证pMGL3启动子在非生物逆境胁迫下的驱动活性。再根据启动子序列分析结果,去除不同的顺式作用元件,构建不同长度pMGL3启动子驱动报告基因GUS表达载体,农杆菌介导法转化烟草叶盘,以确定pMGL3启动子的最短活性序列。结果显示:pMGL3启动子长1 554bp,存在多种与非生物逆境胁迫应答相关的调控元件,在干旱、高盐、低温胁迫及脱落酸、乙烯诱导下驱动MGL3基因增量表达,用以驱动GUS基因转化玉米愈伤组织,在高渗、高盐、低温胁迫及脱落酸诱导下具有驱动活性,且截短至325bp仍可保持驱动活性。研究表明,pMGL3启动子的确有非生物逆境诱导启动活性,进一步验证其作用机理后可运用于玉米抗逆转基因研究。     

Evaluation of the Protective Activities of a Late Embryogenesis Abundant (LEA) Related Protein,Cor15am,during Various Stresses in Vitro

Arabidopsis Cor15am is a late embryogenesis abundant (LEA) related protein that has been shown to exhibit cryoprotective activity in vitro. In this study, we further investigated the mechanisms by which Cor15am protects substrates from inactivation. Although Cor15am did not exhibit refolding activity, it showed protective activity against various stresses in vitro. This might be attributable to the activity of Cor15am in attenuating the aggregation of the substrates. Our data indicate that Cor15am functions as a protectant against various stresses by preventing protein aggregation.     

利用植物生产异源蛋白的研究进展

植物作为生产异源蛋白的生物反应器,近年来颇受关注,与复杂,昂贵的以细胞培养为基础的表达系统相比,具有安全、廉价及规模化生等特点。作者简述了利用植物生产外源蛋白的主要策略及异源基因在植物中表达的研究进展。     

Investigation on bioactive protection of LEA protein to insulin by molecular simulation

Nowadays various protein medicines are increasingly playing a key role on treatment of many diseases, while the bioactivity of such kinds of protein medicines is unstable because of their heat sensitivity. In order to explore a protective method and to explain the protective mechanism of protein medicines, the bioactive protection of the late embryogenesis abundant (LEA) protein to insulin was researched by molecular dynamics simulation. The results suggest that LEA proteins preserve the native structure of the insulin well. Compared with the desiccated insulin without any protection, the structure of insulin protected by LEA protein have smaller values, more centralised configurational space, lower free energies and structural cluster more closer to the native structure. All the above results prove that the LEA protein does protect the bioactivity of insulin during desiccation. The LEA protein is a perfect bioactive protectant for heat-sensitive protein medicines. Such LEA proteins can match the shape of insulin and form multisite binding interaction with insulin.     

Investigation on bioactive protection of the amino acids derived from LEA protein on insulin by molecular simulation

Nowadays heat-sensitive protein medicines are increasingly showing their importance in the treatment of various diseases. Their popularisation and application are meeting a great challenge because of their heat lability. In this study, human insulin as a heat-sensitive protein medicine and 66 amino acids derived from a Group 3 late embryogenesis abundant protein fragment as a complex bioactive protectant, were chosen to be investigated to determine whether these amino acids can be used to protect the insulin from denaturation due to drying. The experiments were carried out by using a replica exchange molecular dynamics (REMD) simulation and GROMACS software with Gromos96 (53a6) force field. The REMD results indicate that those amino acids can effectively prevent the reversal between hydrophilic and hydrophobic surface. Both the configurations and secondary structures of the protected insulin were preserved very well. The H-bonding and electrostatic interactions between the insulin and the protectant play key roles in the bioactive protection of insulin. These results agree well with the water replacement hypothesis. All the results prove that these amino acids are a perfect bioactive protectant for heat-sensitive protein medicines.     

Two New Group 3 LEA Genes of Wheat and Their Functional Analysis in Yeast

The group 3 late embryogenesis abundant （LEA） proteins are thought to protect cells from stresses associated with dehydration during periods of water deficit. To investigate the functions of different members of the group 3 LEA genes, we isolated and characterized two new group 3 LEA genes, namely TaLEA2 and TaLEA3, from wheat （Triticum aestivum L.） and introduced TaLEA2 and TaLEA3 into Saccharmyces cerevisiae to examine the effect of these genes on yeast cell tolerance to osmotic, salt, and cold stresses. The TaLEA2 gene encoded a protein of 211 amino acids and possessed five repeats of 11-mer amino acid motifs. The TaLEA3 gene encoded a polypeptide of 211 amino acids with nine repeated units. Overexpression of TaLEA2 and TaLEA3 improved stress tolerance in transgenic yeast cells when cultured in medium containing sorbitol, salt and-20℃ freezing treatments respectively. However, the yeast transformants with TaLEA2 seemed to be more tolerant to hyperosmotic and freezing stress than transformants with TaLEA3. This implies that a close relationship exists between function and the number of repeats of the 11- mer amino acid motif in the group 3 LEA protein.     

A Putative LEA Protein,but no Trehalose,is Present in Anhydrobiotic Bdelloid Rotifers

Some eukaryotes, including bdelloid rotifer species, are able to withstand desiccation by entering a state of suspended animation. In this ametabolic condition, known as anhydrobiosis, they can remain viable for extended periods, perhaps decades, but resume normal activities on rehydration. Anhydrobiosis is thought to require accumulation of the non-reducing disaccharides trehalose (in animals and fungi) or sucrose (in plant seeds and resurrection plants), which may protect proteins and membranes by acting as water replacement molecules and vitrifying agents. However, in clone cultures of bdelloid rotifers Philodina roseola and Adineta vaga, we were unable to detect trehalose or other disaccharides in either control or dehydrating animals, as determined by gas chromatography. Indeed, trehalose synthase genes (tps) were not detected in these rotifer genomes, suggesting that bdelloids might not have the capacity to produce trehalose under any circumstances. This is in sharp contrast to other anhydrobiotic animals such as nematodes and brine shrimp cysts, where trehalose is present during desiccation. Instead, we suggest that adaptations involving proteins might be more important than those involving small biochemicals in rotifer anhydrobiosis: on dehydration, P. roseola upregulates a hydrophilic protein related to the late embryogenesis abundant (LEA) proteins associated with desiccation tolerance in plants. Since LEA-like proteins have also been implicated in the desiccation tolerance of nematodes and micro-organisms, it seems that hydrophilic protein biosynthesis represents a common element of anhydrobiosis across several biological kingdoms.