Complex molecular mechanisms determine fitness of plants to biotic and abiotic stresses

The mode of growth and development of plants does not allow them to change their habitat upon stress imposition. Through the course of evolution, plants have acquired complex molecular pathways to deal with abiotic and biotic factors to ensure their survival. The changing climatic conditions have led to unprecedented weather patterns resulting in increased crop losses. Similarly, the spread of pathogens in an era of increasing international trade has resulted in introduction and adaptation of these pathogens to new areas and cause frequent epidemics. There is an increasing need to understand the molecular mechanisms underlying stress responses in plants and envision ways to develop new crop varieties with improved features.

     

植物营养元素胁迫相关microRNA研究进展

营养元素以多种方式参与植物光合作用、呼吸作用、能量代谢和信号转导等生理和代谢过程，是植物生长发育、产量和品质的重要物质基础。MicroRNAs（miRNAs）是一类存在于真核生物体中的内源性非编码单链RNA，在植物适应营养元素胁迫过程中发挥着重要作用。综述了近年来miRNA参与调控磷、硫、氮、钾等营养元素胁迫的研究进展，并对今后miRNA在植物营养元素胁迫领域的研究作出了展望，以期为利用miRNA进行营养元素高效利用分子育种提供新的思路。     

cDNA-AFLP技术及其在植物基因表达研究中的应用

cDNA-AFLP技术是一种新的研究基因表达的技术,具有重复性好、稳定、可靠的特点,可对生物体转录组进行全面、系统的分析,广泛应用于基因表达特性研究、植物遗传标记分析和分离植物基因等方面.近年来随着技术的不断进步,设备的不断改进,许多新的研究方法不断的产生,该技术取得了迅速的发展.本文就cDNA-AFLP技术的原理、技术特点及其在植物基因表达研究中的应用进行了综述.     

Macroevolutionary and macroecological approaches to understanding the evolution of stress tolerance in plants

Environmental stress response in plants has been studied using a wide range of approaches, from lab-based investigation of biochemistry and genetics, to glasshouse studies of physiology and growth rates, to field-based trials and ecological surveys. It is also possible to investigate the evolution of environmental stress responses using macroevolutionary and macroecological analyses, analysing data from many different species, providing a new perspective on the way that environmental stress shapes the evolution and distribution of biodiversity. “Macroevoeco” approaches can produce intriguing results and new ways of looking at old problems. In this review, we focus on studies using phylogenetic analysis to illuminate macroevolutionary patterns in the evolution of environmental stress tolerance in plants. We follow a particular thread from our own research—evolution of salt tolerance—as a case study that illustrates a macroevolutionary way of thinking that opens up a range of broader questions on the evolution of environmental stress tolerances. We consider some potential future applications of macroevolutionary and macroecological analyses to understanding how diverse groups of plants evolve in response to environmental stress, which may allow better prediction of current stress tolerance and a way of predicting the capacity of species to adapt to changing environmental stresses over time.     

重金属胁迫下内生菌对宿主植物的解毒机制

采用内生菌联合植物修复是土壤重金属污染修复理论研究和应用实践的新思路。较之根际促生菌,内生菌因生存环境稳定且与植物联系更加紧密,在实际应用中具有更大价值。在重金属胁迫下,部分具有特定功能的细菌可进入植物体内成为内生菌,这些内生菌通常在重金属吸收、耐受和解毒方面具有优良的特性,而且可以协同宿主植物耐受重金属胁迫,表现在直接或间接降低植物体内重金属胁迫强度和提高植物本身对重金属的耐受性两方面。系统分析了内生菌对宿主植物的解毒机制,综述了近年来内生菌增强植物重金属耐受性的研究,展望了重金属胁迫下植物和内生菌互作机制的研究思路和方向。     

Plant salt tolerance

Soil salinity is a major abiotic stress in plant agriculture worldwide. This has led to research into salt tolerance with the aim of improving crop plants. However, salt tolerance might have much wider implications because transgenic salt-tolerant plants often also tolerate other stresses including chilling, freezing, heat and drought. Unfortunately, suitable genetic model systems have been hard to find. A recently discovered halophytic plant species, Thellungiella halophila, now promises to help in the detection of new tolerance determinants and operating pathways in a model system that is not limited to Arabidopsis traits or ecotype variations.     

Plant sphingolipids: structural diversity,biosynthesis, first genes and functions

In mammals and Saccharomyces cerevisiae, sphingolipids have been a subject of intensive research triggered by the interest in their structural diversity and in mammalian pathophysiology as well as in the availability of yeast mutants and suppressor strains. More recently, sphingolipids have attracted additional interest, because they are emerging as an important class of messenger molecules linked to many different cellular functions. In plants, sphingolipids show structural features differing from those found in animals and fungi, and much less is known about their biosynthesis and function. This review focuses on the sphingolipid modifications found in plants and on recent advances in the functional characterization of genes gaining new insight into plant sphingolipid biosynthesis. Recent studies indicate that plant sphingolipids may be also involved in signal transduction, membrane stability, host-pathogen interactions and stress responses.     

Programmed cell death in cell cultures

In plants most instances of programmed cell death (PCD) occur in a number of related, or neighbouring, cells in specific tissues. However, recent research with plant cell cultures has demonstrated that PCD can be induced in single cells. The uniformity, accessibility and reduced complexity of cell cultures make them ideal research tools to investigate the regulation of PCD in plants. PCD has now been induced in cell cultures from a wide range of species including many of the so-called model species. We will discuss the establishment of cell cultures, the fractionation of single cells and isolation of protoplasts, and consider the characteristic features of PCD in cultured cells. We will review the wide range of methods to induce cell death in cell cultures ranging from abiotic stress, absence of survival signals, manipulation of signal pathway intermediates, through the induction of defence-related PCD and developmentally induced cell death.     

Function and evolution of grana

Chloroplasts are descended from cyanobacteria, and they retain many features of the cyanobacterial photosynthetic apparatus. However, land-plant chloroplasts have a strikingly different thylakoid membrane organization to that of cyanobacteria. Usually the two photosystems are laterally segregated; Photosystem II is concentrated in complex stacked-membrane structures known as grana. The function of grana has long been debated. Recent studies on membrane organization in chloroplasts, cyanobacteria and purple bacteria now offer a new perspective. I argue that grana allow the presence of a large light-harvesting antenna for Photosystem II, without excessively restricting electron transport. Other organisms solve this problem in different ways. Land plants evolved from macroalgae that were adapted to high light conditions; they evolved grana as a new solution to the problem of efficient photosynthesis in shade.     

Plant responses to environmental stress.

Considerable progress is being made in identifying genes that are important for tolerance to abiotic stress and in defining stress-responsive gene promoters and signal-transduction pathways. Although genetically engineered crop plants with greater resistance to environmental stress have not yet been produced, research is at a turning point where correlative changes can now be tested for effectiveness in conferring stress tolerance.     

The perception of gravity by a plant

Ever since geotropism was first studied in plants, attempts have been made to create model systems which might simulate the perception by a plant of a gravitational change. The most resilient of these models, the so-called statolith theory, has now enjoyed a run of over 75 years and demonstrates its viability by reappearing in many different forms. It has shown its value by anticipating the now well understood graviperception mechanism in the Chara rhizoid and this will be described. However, it is unlikely that many features of this relatively simple system can be translated to the higher plant. We now know precisely, at least in many primary roots, the distribution and approximate numbers of the cells that perceive gravity. There is no reason to assume that an identical system operates in shoots, since it is now clear that the fundamental hormonal bases of these two systems are different. We also know much about the ultrastructure of many geoperceptive cells, but apart from speculative models a satisfactory explanation of this very rapid and flexible system eludes us. A possible model system is proposed and ways of testing it in zero gravity are suggested.     

植物非生物胁迫诱导启动子顺式作用元件的研究方法

非生物胁迫严重影响植物生长发育,降低作物产量。植物通过各种途径忍受或抵抗非生物胁迫,主要表现是各种抗非生物胁迫基因的表达。基因表达受其上游启动子及转录因子的调控,目前对抗非生物胁迫诱导启动子顺式作用元件及转录因子的研究成为热点。本文综述了植物非生物胁迫诱导启动子顺式作用元件及转录因子的研究方法,并展望了顺式作用元件及转录因子研究的方向及前景。     

植物弱光逆境生理研究综述

弱光是目前影响设施生产的重要不利环境因素之一。本文综述了弱光对植物生长发育 和光合特性的影响及其信号转导途径,并在此基础上讨论了植物对弱光的适应途径和今后植 物弱光逆境生理的研究方向。     

The continuing search for antitumor agents from higher plants

Plant secondary metabolites and their semi-synthetic derivatives continue to play an important role in anticancer drug therapy. In this short review, selected single chemical entity antineoplastic agents from higher plants that are currently in clinical trials as cancer chemotherapy drug candidates are described. These compounds are representative of a wide structural diversity. In addition, the approaches taken toward the discovery of anticancer agents from tropical plants in the laboratory of the authors are summarized. The successful clinical utilization of cancer chemotherapeutic agents from higher plants has been evident for about half a century, and, when considered with the promising pipeline of new plant-derived compounds now in clinical trials, this augurs well for the continuation of drug discovery research efforts to elucidate additional candidate substances of this type.     

丛枝菌根（AM）与植物的抗逆性

菌根是土壤中的菌根真菌与高等植物的根系形成的一种联合体 ,是自然界中一种普遍的植物共生现象。除十字花科、莎草科、藜科等少数几个科不能或不易形成菌根外 ,大多数植物包括苔藓、蕨类、裸子植物、被子植物都能形成菌根。 AM是其中的一类 ,也是目前研究较多的一类。AM的内外生菌丝不仅增加了根系的吸收面积 ,还能分泌多种有益物质。所以 ,AM对植物养分、水分的吸收与运输 ,对植物抵抗各种胁迫是十分有益的。1　AM与植物的抗旱性随着全球干旱面积的不断增加 ,淡水资源的日益减少 ,干旱研究已受到人们极大的关注。由于菌根的特殊作用和…     

植物弱光逆境生理研究综述

弱光是目前影响设施生产的重要不利环境因素之一。本文综述了弱光对植物生长发育和光合特性的影响及其信号转导途径,并在此基础上讨论了植物对弱光的适应途径和今后植物弱光逆境生理的研究方向。     

植物低氧胁迫伤害与适应机理的研究进展

不良的通气条件导致了正常生长发育的植物生理性缺氧,低氧胁迫是高等植物主要的非生物胁迫因素之一。本文综述了低氧胁迫对植物生长、植株形态的影响,低氧胁迫对植物内部水分、养分吸收的变化,呼吸代谢途径的变化、激素代谢的变化,氧化系统的变化的影响,以及低氧胁迫过程中植物体内信号的传导、基因的表达、蛋白质的合成等,在不同层面分析了低氧胁迫对植物的伤害及植物对低氧逆境适应机理的最新研究成果。     

植物水通道蛋白的干旱应答机制研究进展

干旱胁迫是严重影响全球作物生产的非生物胁迫之一,研究植物耐旱机制已成为一个重要领域。水通道蛋白是一类特异、高效转运水及其它小分子底物的膜通道蛋白,在植物中具有丰富的亚型,参与调节植物的水分吸收和运输。近10年来,水通道蛋白在植物不同生理过程中的作用,一直受到研究人员的关注,特别是在非生物胁迫方面,而研究表明水通道蛋白在干旱胁迫下对植物的耐旱性起着至关重要的作用,能维持细胞水分稳态和调控环境胁迫快速响应。水通道蛋白在植物耐旱过程中的调控机制及功能较复杂,而关于其应答机制和不同亚型功能性研究的报道甚少。该文综述了植物水通道蛋白的分类、结构、表达调控和活性调节,分别从植物水通道蛋白响应干旱表达调控机制、水通道蛋白基因表达的时空特异性、水通道蛋白基因的表达与蛋白丰度,水通道蛋白基因的耐旱转化四个方面阐明干旱胁迫下植物水通道蛋白的表达,重点阐述其参与植物干旱胁迫应答的作用机制,并提出水通道蛋白研究的主要方向。