Progress and challenges for abiotic stress proteomics of crop plants

Plants are continually challenged to recognize and respond to adverse changes in their environment to avoid detrimental effects on growth and development. Understanding the mechanisms that crop plants employ to resist and tolerate abiotic stress is of considerable interest for designing agriculture breeding strategies to ensure sustainable productivity. The application of proteomics technologies to advance our knowledge in crop plant abiotic stress tolerance has increased dramatically in the past few years as evidenced by the large amount of publications in this area. This is attributed to advances in various technology platforms associated with MS‐based techniques as well as the accessibility of proteomics units to a wider plant research community. This review summarizes the work which has been reported for major crop plants and evaluates the findings in context of the approaches that are widely employed with the aim to encourage broadening the strategies used to increase coverage of the proteome     

蛋白质组学在植物逆境胁迫研究中的进展

蛋白质组学是后基因组时代研究的热点领域之一,自从蛋白质组这个概念被提出以来,其研究一直受到广泛关注,其研究技术也有了极大地进步。植物时刻都面临各种非生物胁迫,包括干旱、冷、盐、金属等,在长期进化过程中,植物形成独特的机制来响应逆境,然而目前对于植物如何适应逆境的分子机制尚未完全阐明。因此蛋白质组学作为一种强有力的研究技术手段,将为研究植物响应胁迫的分子机制提供理论支撑。介绍了蛋白质组学的产生背景、研究技术手段及植物在各种胁迫条件下的蛋白质组学研究、植物亚细胞器的蛋白质组学研究状况,同时对植物蛋白质组学的发展前景进行了展望。     

Comparative physiological,ultrastructural and proteomic analyses reveal sexual differences in the responses of Populus cathayana under drought stress

Drought is a major abiotic stress, limiting the survival and growth of young plants. However, little is known about sex‐dependent responses to drought at the proteome level. In this study, we carried out investigations on comparative proteomics, combined with physiological and organelle structure analyses, in males and females of Populus cathayana Rehd. Three‐month‐old poplar cuttings were treated at 30% of field capacity and at 100% field capacity as a control in a greenhouse for 40 days. Drought greatly inhibited plant growth, damaged the photosynthetic system and destructed the structures of chloroplasts, mitochondria and cellular membranes. However, males suffered less from the adverse effects of drought than did females. Using 2‐DE, 563 spots were detected, of which 64 spots displayed significant drought effect and 44 spots displayed a significant sex by drought interaction effect. The results suggest that the different responses to drought stress detected between the sexes have a close relationship to the changes in the expression of sex‐dependent proteins, including, e.g. photosynthesis‐related proteins, homeostasis‐related proteins and stress response proteins. These proteins could contribute to a physiological advantage under drought, giving potential clues for understanding sexual differences in the performance of plants in different environments.     

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.     

Proteomics Reveals New Salt Responsive Proteins Associated with Rice Plasma Membrane

The signaling processes in plants that initiate cellular responses to biotic and abiotic factors are believed to be located in the plasma membrane (PM). A better understanding of the PM proteome response to environmental stresses might lead to new strategies for improving stress-tolerant crops. A sub-cellular proteomics approach was applied to monitor changes in abundance of PM-associated protein in response to salinity, a key abiotic stress affecting rice productivity worldwide. Proteome was extracted from a root plasma-membrane-rich fraction of a rice salt tolerant variety, IR651, grown under saline and normal conditions. Comparative two-dimensional electrophoresis revealed that 24 proteins were differentially expressed in response to salt stress. From these, eight proteins were identified by mass spectrometry analysis. Most of the proteins identified are likely to be PM-associated and are known to be involved in several important mechanisms of plant adaptation to salt stress. These include regulation of PM pumps and channels, membrane structure, oxidative stress defense, signal transduction, protein folding, and the methyl cycle. To investigate the correlation between mRNA and protein level in response to salinity, we performed quantitative Real-Time PCR analysis of three genes that were salt responsive at the protein level, including 1,4-Benzoquinone reductase, a putative remorin and a hypersensitive induced response protein. No concordance was detected between the changes in levels of gene and protein expression. Our results indicate that the proteomics approach is suitable for expression analysis of membrane associated proteins under salt stress.     

植物响应非生物胁迫的磷酸化修饰组学研究进展

植物具有固着生活的特点,高温、低温、干旱和盐等生境中常见的非生物胁迫会严重影响植物的生长发育。蛋白质磷酸化是植物应对非生物胁迫的重要机制,主要通过蛋白质的磷酸化和去磷酸化修饰来调控植物细胞对外界胁迫的应激反应,在植物细胞快速传递胁迫信号并激活对胁迫环境的形态、生理和分子水平适应机制的过程中起重要作用。该文主要介绍了植物磷酸化蛋白质的富集、检测和鉴定技术,并对近年来国内外有关植物响应高温、低温、干旱、淹水、盐、养分亏缺和元素毒害等非生物胁迫的磷酸化修饰蛋白组学研究进展进行综述。     

Proteomic analysis of β-aminobutyric acid priming and abscisic acid – induction of drought resistance in crabapple (Malus pumila): effect on general metabolism, the phenylpropanoid pathway and cell wall enzymes

In a variety of herbaceous, model and crop plants, DL- β -aminobutyric acid (BABA), has been shown to enhance both biotic and abiotic stress resistance by potentiating rather than inducing resistance responses but studies in woody plants are lacking. In the present study, two-dimensional difference in-gel electrophoresis (DIGE) was used to quantify differences in protein abundance in leaf tissue from BABA-treated, abscisic acid (ABA)-treated and untreated (control) plants during a 10 d drought stress. ABA-treated seedlings were most resistant to water loss followed by BABA-treated seedlings and then untreated seedlings. Although some similarity was observed in the proteome of ABA- and BABA-treated seedlings, a dramatic shift in the proteome occurred earlier in ABA-treated seedlings. Some proteins showed almost identical patterns of increase or decrease in abundance in both BABA- and ABA-treated seedlings, supporting the concept that BABA-induced abiotic stress resistance in plants is achieved by potentiating an ABA-regulated pathway. Some proteins, however, were induced or suppressed only in BABA-primed plants, indicating that BABA may also mediate resistance via some ABA-independent pathways. Based on the putative function of the identified proteins, we propose that changes in cell wall enzymes and a suppression of lignin biosynthesis may play a specific role in BABA-primed drought resistance.     

Model plant systems in salinity and drought stress proteomics studies: a perspective on Arabidopsis and Sorghum

More than a decade after the sequencing of its genome, Arabidopsis still stands as the epitome of a model system in plant biology. Arabidopsis proteomics has also taught us great lessons on different aspects of plant growth, development and physiology. Without doubt our understanding of basic principles of plant biology would not have been this advanced if it were not for knowledge gained using Arabidopsis as a model system. However, with the projections of global climate change and rapid population growth, it is high time we evaluate the applicability of this model system in studies aimed at understanding abiotic stress tolerance and adaptation, with a particular emphasis on maintaining yield under hot and dry environmental conditions. Because of the innate nature of sorghum's tolerance to drought and moderate tolerance to salinity stresses, we believe sorghum is the next logical model system in such studies amongst cereals. In this acute view, we highlight the importance of Arabidopsis as a model system, briefly discuss its potential limitations in drought and salt stress studies, and present our views on the potential usefulness of sorghum as a model system for cereals in drought and salinity stress proteomic studies.     

Nitric oxide function in plant abiotic stress

Abiotic stress is one of the main threats affecting crop growth and production. An understanding of the molecular mechanisms that underpin plant responses against environmental insults will be crucial to help guide the rational design of crop plants to counter these challenges. A key feature during abiotic stress is the production of nitric oxide (NO), an important concentration dependent, redox‐related signalling molecule. NO can directly or indirectly interact with a wide range of targets leading to the modulation of protein function and the reprogramming of gene expression. The transfer of NO bioactivity can occur through a variety of potential mechanisms but chief among these is S‐nitrosylation, a prototypic, redox‐based, post‐translational modification. However, little is known about this pivotal molecular amendment in the regulation of abiotic stress signalling. Here, we describe the emerging knowledge concerning the function of NO and S‐nitrosylation during plant responses to abiotic stress.     

Emerging tools,concepts and ideas to track the modulator genes underlying plant drought adaptive traits: An overview

Crop vulnerability to multiple abiotic stresses is increasing at an alarming rate in the current global climate change scenario, especially drought. Crop improvement for adaptive adjustments to accomplish stress tolerance requires a comprehensive understanding of the key contributory processes. This requires the identification and careful analysis of the critical morpho-physiological plant attributes and their genetic control. In this review we try to discuss the crucial traits underlying drought tolerance and the various modes followed to understand their molecular level regulation. Plant stress biology is progressing into new dimensions and a conscious attempt has been made to traverse through the various approaches and checkpoints that would be relevant to tackle drought stress limitations for sustainable crop production.     

Identification of changes in Triticum aestivum L. leaf proteome in response to drought stress by 2D-PAGE and MALDI-TOF/TOF mass spectrometry

Drought is an abiotic stress that strongly influences plant growth, development and productivity. To gain a better understanding of the drought-stress responses at physiological and molecular level in wheat plants (Triticum aestivum cv. KTC86211), we performed a comparative physiological and proteomics analysis. Eight-day-old wheat seedlings were treated with polyethylene glycol-simulated drought stress for 0, 24, 48 and 72 h. Drought treatment resulted in alterations of morphology, increased relative electrolyte leakage and reduced length and weight on leaf and root. Stress-induced proteome changes were analyzed by two-dimensional gel electrophoresis in conjunction with MALDI-TOF/TOF. Twenty-three spots differed significantly between control and treated plants following 48 h of drought stress, with 19 upregulated, and 4 downregulated, in leaf tissues. All of the differentially expressed protein spots were identified, revealing that the majority of proteins altered by drought treatment were involved in reactive oxygen species scavenging enzymes and photosynthesis. Other proteins identified were involved in protein metabolism, cytoskeleton structure, defense response, acid metabolism and signal transduction. All proteins might contribute cooperatively to reestablish cellular homeostasis under drought stress. The present study not only provides new insights into the mechanisms of acclimation and tolerance to drought stress in wheat plants, but also provides clues for improving wheat’s drought tolerance through breeding or genetic engineering.     

Analysis of drought responsive proteins in wheat (Triticum durum) by 2D-PAGE and MALDI-TOF mass spectrometry

Drought is an abiotic stress that strongly influences plant growth, development and productivity. By proteomics study it is possible to identify the complex mechanism of water-stress response. The aim of this research was the analysis of wheat (Triticum durum) proteome changes under stress conditions by applying a severe water deficit treatment for 7 days. Stress-induced proteome changes were analyzed by two-dimensional gel electrophoresis in conjunction with matrix-assisted laser desorption ionization-time of flight mass spectrometry. Thirty-six protein spots showed a reproducible significant change between control and stressed samples. The reasonable implications in drought response of the identified proteins were discussed. Results provide new insights that can lead to a better understanding of the molecular basis of drought-sensitivity in plants. Therefore, the obtained data could suggest the development of drought resistant wheat varieties, in order to improve agricultural production in dry regions.