转基因改良植物的胁迫耐性

干旱、盐碱和低温等逆境是严重影响栽培植物生产的非生物胁迫因素。导入外源目的的基因已发展成为改良作物对逆境胁迫耐性的新途径。现今已应用于植物胁迫改良的基因包括编码活性氧清除酶类、膜修饰酶类、胁迫诱导蛋白和渗调物质合成酶等基因。     

一种新的与渗调蛋白基因启动子结合的蛋白基因的分离

渗调蛋白基因可受多种外界环境因子的诱导表达 ,并与植物细胞的渗透调节、抗逆境及植物抗病性等重要的生理过程有着密切关系 ,通过寻找与渗调蛋白基因启动子中FA区域DNA结合的蛋白 ,克隆参与该基因表达调控的反式作用因子 ,有利于明确渗调蛋白基因在转录水平上的调控机制 ,揭示外界环境因子通过信号传导系统诱导渗调蛋白基因表达的过程 .利用近年来发展起的酵母单杂交系统 ,从适盐的烟草悬浮细胞的cDNA文库中分离到 1个可与渗调蛋基因启动子中FA片段结合的蛋白因子的基因OPBP1.核酸序列分析表明OPBP1包含有一个完整的阅读框架 ,可编码 2 77个氨基酸 ,氨基酸序列的比较分析表明该蛋白与近年来发现的一类新的DNA结合蛋白如EREBP ,AP ,ANT等具有相同的保守区 ,其中一些氨基酸完全相同 ,OPBP1与EREBP3最接近 ,同属该类新的DNA结合蛋白的第 1组 ,仅有 1个保守区 .     

植物C_2H_2型锌指蛋白的研究进展

锌指蛋白是转录因子的一种,对真核生物的生长发育及逆境胁迫的耐受能力都有着重要关系,而植物C2H2型锌指蛋白是研究较多、较为明确的一种锌指蛋白,该蛋白大部分锌指结构具有一段高度保守的氨基酸序列QALGGH,这是植物中独有的特征,且据报道该C2H2型锌指蛋白与逆境胁迫是相关的。本文主要综述了植物C2H2型锌指蛋白的分类、结构和功能,植物C2H2型锌指蛋白与DNA、RNA和蛋白质的相互作用,以及概述了与盐胁迫、低温胁迫、干旱胁迫、氧胁迫和光胁迫等逆境胁迫相关的植物C2H2型锌指蛋白,最后还对其进一步的深入研究进行了展望,这就为日后利用基因工程技术改良作物品质、提高作物的抗逆性提供了有利条件。     

植物钙感受器及其介导的逆境信号途径

钙信号是植物生长发育和逆境响应的重要调控因子, 是植物生理与逆境生物学研究领域中的热点之一。当植物细胞受到外界逆境刺激时, 其胞内会产生具有时空特异性的Ca2+信号变化, 这种变化首先被胞内钙感受器所感知并解码, 再由钙感受器互作蛋白将信号传递到下游, 从而激活下游早期响应基因的表达或相关离子通道的活性, 最终产生特异性逆境响应。植物细胞通过感知胞内钙信号的变化如何识别来自外界不同性质或不同强度的刺激, 是近几年植物生物学家所关注的科学问题。文章主要总结了近几年在植物钙感受器研究领域中的最新进展, 包括钙依赖蛋白激酶(CDPKs)、钙调素(CaMs)、类钙调素蛋白(CMLs)、类钙调磷酸酶B蛋白(CBLs)及其互作蛋白激酶(CIPKs)等的结构、功能及其介导的逆境信号途径, 并提供新的见解和展望。     

植物耐盐性的分子生物学研究进展

研究证明了植物的耐盐机制十分复杂,安与植物的小分子物质的积累,离子摄入和区域化,以及基因表达和大分子蛋白质的合成有关,如调渗蛋白、通道蛋白、晚期胚胎发生富集蛋白。同时,利用克隆技术分离到了一些盐诱导基因。现将这部分工作做一综述。     

植物耐盐的分子机理研究进展

综述了与植物耐盐性密切相关的小分子渗透物质（脯氨酸,甜菜碱,多元醇,多胺,果聚糖）,晚期胚胎发生富集蛋白（LEA）,调渗蛋白（OSM）,水通道蛋白,K^ 通道蛋白和ATPase等的合成及其相关基因的表达。     

LEA蛋白与植物抗逆性

植物受到逆境胁迫后,LEA蛋白大量表达,可以减轻逆境引起的伤害。本文对LEA蛋白的种类、特性和功能,LEA蛋白基因结构及其表达调控,以及LEA基因表达和LEA蛋白积累与植物抗逆性的关系等方面的研究进展作了简要综述。     

植物抗旱耐盐基因的研究进展

近几年许多与植物抗旱耐盐相关基因被克隆和分析,同时通过转基因技术将这些基因转到植物中异源表达,能显著提高转基因植物的抗旱耐盐能力。这些基因主要包括渗透调节基因、蛋白类基因(如信号传导中的蛋白激酶基因)及转录因子等。在逆境条件下,渗透调节基因通过合成脯氨酸、甜菜碱、糖类和多胺类等渗透调节物质维持植物中的渗透平衡;蛋白激酶基因产物是细胞信号传导中的组分,这些基因能促进植物对干旱失水反应和逆境信号的传递,启动抗逆基因的表达;转录因子通过与相关基因的特异性结合来调控其表达,进而产生相关调控蛋白等物质增强植物在逆境中的生存能力。本文主要综述了这三类抗逆基因的研究现状及其生物学机理,讨论并分析这些基因在应用中尚待解决的问题,为发掘更多的抗逆性的基因资源和进一步开展分子育种工作提供参考。     

植物抗旱、耐盐基因概述

干旱和盐渍化是影响植物生长发育的重要逆境因子。逆境会诱导植物特定基因表达,以保护细胞免受逆境的危害。目前所报道的与植物抗旱、耐盐性相关的基因可分为四类：渗透保护物质生物合成的基因、编码与水分胁迫相关的功能蛋白基因、与信号传递和基因表达相关的调控基因、与细胞排毒抗氧化防御能力相关的酶基因。     

植物细胞壁伸展蛋白的功能与利用

伸展蛋白是一类富含羟脯氨酸的糖蛋白,是植物细胞壁中重要的结构蛋白。伸展蛋白家族基因广泛存在于多种植物中,参与植物细胞壁网络结构形成与修饰、植物细胞伸长、根生长发育等过程,并且影响植物机械强度、倒伏抗性和各种逆境胁迫反应。本文拟从蛋白结构、进化关系、生物学功能等方面介绍植物伸展蛋白近期研究进展,并初步提出了此类基因在农作物和能源植物遗传改良中的利用。     

Plant proteome changes under abiotic stress--contribution of proteomics studies to understanding plant stress response

Plant acclimation to stress is associated with profound changes in proteome composition. Since proteins are directly involved in plant stress response, proteomics studies can significantly contribute to unravel the possible relationships between protein abundance and plant stress acclimation. In this review, proteomics studies dealing with plant response to a broad range of abiotic stress factors--cold, heat, drought, waterlogging, salinity, ozone treatment, hypoxia and anoxia, herbicide treatments, inadequate or excessive light conditions, disbalances in mineral nutrition, enhanced concentrations of heavy metals, radioactivity and mechanical wounding are discussed. Most studies have been carried out on model plants Arabidopsis thaliana and rice due to large protein sequence databases available; however, the variety of plant species used for proteomics analyses is rapidly increasing. Protein response pathways shared by different plant species under various stress conditions (glycolytic pathway, enzymes of ascorbate-glutathione cycle, accumulation of LEA proteins) as well as pathways unique to a given stress are discussed. Results from proteomics studies are interpreted with respect to physiological factors determining plant stress response. In conclusion, examples of application of proteomics studies in search for protein markers underlying phenotypic variation in physiological parameters associated with plant stress tolerance are given.     

Functions and interaction of plant lipid signalling under abiotic stresses

Lipids are the primary form of energy storage and a major component of plasma membranes, which form the interface between the cell and the extracellular environment. Several lipids — including phosphoinositide, phosphatidic acid, sphingolipids, lysophospholipids, oxylipins, and free fatty acids — also serve as substrates for the generation of signalling molecules. Abiotic stresses, such as drought and temperature stress, are known to affect plant growth. In addition, abiotic stresses can activate certain lipid-dependent signalling pathways that control the expression of stress-responsive genes and contribute to plant stress adaptation. Many studies have focused either on the enzymatic production and metabolism of lipids, or on the mechanisms of abiotic stress response. However, there is little information regarding the roles of plant lipids in plant responses to abiotic stress. In this review, we describe the metabolism of plant lipids and discuss their involvement in plant responses to abiotic stress. As such, this review provides crucial background for further research on the interactions between plant lipids and abiotic stress.     

植物DNA甲基化变异对生物和非生物胁迫的响应机制

高等植物具有复杂的机制使其对环境的变化做出响应,这种机制是通过长期进化建立起来的.它们能够对出现的生物和非生物胁迫产生响应.在分子水平上,植物对各种胁迫的响应是受多基因表达变化调控的,包括植物激素水杨酸、脱落酸等信号途径在整合、协调植物胁迫过程中起关键作用.近年来的研究表明,在植物响应胁迫这一过程中还进行着表观遗传调控...     

植物耐盐性机理研究进展

在盐胁迫下环境中某些植物会在发生一些变化。从生理学、生物化学、盐胁迫分子学机制的角度对植物对盐胁迫的反应研究进行了回顾,并提供了一些目前知识水平上能增加植物盐耐性的方法。解释了在盐胁迫下植物的离子吸收、相溶性物质、抗氧化酶、植物激素、光合作用等方面的变化规律,其中也有耐盐植物功能调节的研究,这有助于从多学科研究的角度评估盐胁迫的生态重要性。     

Crop responses to drought and the interpretation of adaptation

Drought is a multidimensional stress affecting plants at various levels of their organization. The effect of and plant response to drought at the whole plant and crop level is most complex because it reflects the integration of stress effects and responses at all underlying levels of organization over space and time. This review discusses some of the major aspects of crop response to drought stress which are relevant for plant breeding. Emphasis is given to whole plant aspects which are too often disregarded when conclusions are drawn from molecular studies towards the genetic improvement of crop drought resistance. Topics discussed are seedling emergence and establishment, plant phenology, leaf area, water deficit and assimilation, osmotic adjustment, the root and the formation of yield. The discussion is concluded with the interpretation of crop adaptation to drought conditions in its agronomic sense. Conclusions are drawn regarding plant breeding for drought-prone conditions.     

Plant cell organelle proteomics in response to abiotic stress

Proteomics is one of the finest molecular techniques extensively being used for the study of protein profiling of a given plant species experiencing stressed conditions. Plants respond to a stress by alteration in the pattern of protein expression, either by up-regulating of the existing protein pool or by the synthesizing novel proteins primarily associated with plants antioxidative defense mechanism. Improved protein extraction protocols and advance techniques for identification of novel proteins have been standardized in different plant species at both cellular and whole plant level for better understanding of abiotic stress sensing and intracellular stress signal transduction mechanisms. In contrast, an in-depth proteome study of subcellular organelles could generate much detail information about the intrinsic mechanism of stress response as it correlates the possible relationship between the protein abundance and plant stress tolerance. Although a wealth of reviews devoted to plant proteomics are available, review articles dedicated to plant cell organelle proteins response under abiotic stress are very scanty. In the present review, an attempt has been made to summarize all significant contributions related to abiotic stresses and their impacts on organelle proteomes for better understanding of plants abiotic stress tolerance mechanism at protein level. This review will not only provide new insights into the plants stress response mechanisms, which are necessary for future development of genetically engineered stress tolerant crop plants for the benefit of humankind, but will also highlight the importance of studying changes in protein abundance within the cell organelles in response to abiotic stress.     

The role of mycorrhizae and plant growth promoting rhizobacteria (PGPR) in improving crop productivity under stressful environments

Both biotic and abiotic stresses are major constrains to agricultural production. Under stress conditions, plant growth is affected by a number of factors such as hormonal and nutritional imbalance, ion toxicity, physiological disorders, susceptibility to diseases, etc. Plant growth under stress conditions may be enhanced by the application of microbial inoculation including plant growth promoting rhizobacteria (PGPR) and mycorrhizal fungi. These microbes can promote plant growth by regulating nutritional and hormonal balance, producing plant growth regulators, solubilizing nutrients and inducing resistance against plant pathogens. In addition to their interactions with plants, these microbes also show synergistic as well as antagonistic interactions with other microbes in the soil environment. These interactions may be vital for sustainable agriculture because they mainly depend on biological processes rather than on agrochemicals to maintain plant growth and development as well as proper soil health under stress conditions. A number of research articles can be deciphered from the literature, which shows the role of rhizobacteria and mycorrhizae alone and/or in combination in enhancing plant growth under stress conditions. However, in contrast, a few review papers are available which discuss the synergistic interactions between rhizobacteria and mycorrhizae for enhancing plant growth under normal (non-stress) or stressful environments. Biological interactions between PGPR and mycorrhizal fungi are believed to cause a cumulative effect on all rhizosphere components, and these interactions are also affected by environmental factors such as soil type, nutrition, moisture and temperature. The present review comprehensively discusses recent developments on the effectiveness of PGPR and mycorrhizal fungi for enhancing plant growth under stressful environments. The key mechanisms involved in plant stress tolerance and the effectiveness of microbial inoculation for enhancing plant growth under stress conditions have been discussed at length in this review. Growth promotion by single and dual inoculation of PGPR and mycorrhizal fungi under stress conditions have also been discussed and reviewed comprehensively.     

Environmental gradients and herbivore feeding preferences in coastal salt marshes

Current theories of plant-herbivore interactions suggest that plants may differ in palatability to herbivores as a function of abiotic stress; however, studies of these theories have produced mixed results. We compared the palatability of eight common salt marsh plants that occur across elevational and salinity stress gradients to six common leaf-chewing herbivores to determine patterns of plant palatability. The palatability of every plant species varied across gradients of abiotic stress in at least one comparison, and over half of the comparisons indicated significant differences in palatability. The direction of the preferences, however, was dependent on the plant and herbivore species studied, suggesting that different types of stress affect plants in different ways, that different plant species respond differently to stress, and that different herbivore species measure plant quality in different ways. Overall, 51% of the variation in the strength of the feeding preferences could be explained by a knowledge of the strength of the stress gradient and the type of gradient, plant and herbivore studied. This suggests that the prospects are good for a more complex, conditional theory of plant stress and herbivore feeding preferences that is based on a mechanistic understanding of plant physiology and the factors underlying herbivore feeding preferences.