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| 青杨(Populus cathayana Rehd.)不同种群对干旱胁迫的生理响应及差异蛋白质组学研究 | |
| 其他题名 | Physiological Responses and Comparative Proteomic Analyses of Two Contrasting Populus cathayana Rehd. Populations to Drought Stress |
| 肖向文 | |
| 出版年 | 2008 |
| 学位类型 | 博士 |
| 导师 | 李春阳 |
| 学位授予单位 | 中国科学院成都生物研究所 |
| 中文摘要 | 干旱是世界上发生最为普遍、影响最为严重的环境胁迫因子之一，它在很大程度上限制了农作物的产量。植物的抗旱机理十分复杂，是不同的生理生化机制共同作用的结果。蛋白质组学研究在植物逆境分子机理研究中发挥着越来越重要的作用。杨树具有适应性强、生长快和丰产等特性，不仅具有重要的经济价值和生态价值，也是森林植物的模式树种。本论文以青杨(Populus cathayana Rehd.)为模式植物，选择汉源和乐都两个不同的生态气候种群(分别代表湿润气候种群和干旱气候种群)作为研究材料，采用植物生态、生理生化以及蛋白质组学等方法，研究青杨对干旱胁迫的生理响应以及蛋白质组表达差异，研究成果可为我国干旱半干旱地区营造人工林、防止沙漠化提供理论依据，也为进一步研究抗旱相关基因的功能以及利用基因工程育种技术提高杨树抗旱性提供了一定的线索。主要研究结果如下：\n 1. 青杨不同种群对逐步干旱胁迫的生理响应差异\n 两个种群的生长及生理性状均受到逐步干旱胁迫的影响，这些适应性的变化取决于干旱的时间进程以及干旱的强度，干旱胁迫显著降低了两个青杨种群(干旱种群和湿润种群)生长量和生长速率，杨树通过植物形态结构的调整，有效减少了水分散失。干旱显著提高了类胡萝卜素含量和Car/Chl比值，随着干旱程度的逐步加剧，脯氨酸含量持续增加，而可溶糖含量在干旱初期显著提高，但并不会随着干旱的持续而进一步积累，SOD、POD等抗氧化系统也随着干旱加剧而被激活。两个青杨种群对干旱响应的群体差异也十分显著，与湿润种群相比，干旱种群有更低的生长量和生长速率，但是拥有更强的保护系统，比如更高的类胡萝卜素含量和Car/Chl比值、更高的脯氨酸积累以及更有效的抗氧化酶保护系统，这些使得干旱种群杨树比湿润种群杨树对干旱有更好的耐性。\n 2. 青杨不同种群对逐步干旱胁迫响应的差异蛋白质组学研究\n 经过长期干旱适应后，差异蛋白质组学方法鉴定了15个干旱响应蛋白，这些蛋白的功能涉及转录调节、光合与能量代谢、分子伴侣功能、植物次生代谢、细胞内物质运输以及植物胁迫防卫响应等。其中，苯丙氨酸解氨酶(PAL)在两个种群均上调，暗示次生代谢的调节在杨树长期干旱适应过程中具有重要意义。两个种群中都有一些分子伴侣/HSP大量积累，其中3个sHSP在两个种群中均出现积累，这些HSP类蛋白对于胁迫耐受性具有重要作用。与湿润种群相比，干旱种群在次生代谢方面以及光合方面都具有更强的调节作用。\n 3. 青杨不同种群对持续严重干旱胁迫的生理响应差异及差异蛋白质组学研究\n 用蛋白质组差异表达与生理指标分析相结合的方法研究研究了青杨两个种群对严重干旱胁迫的响应机理，发现了59个差异表达的蛋白，MALDI-TOF质谱分析最终鉴定了40个差异蛋白。这些干旱响应蛋白的功能涉及几个方面：基因表达调控、光合作用与碳代谢、细胞骨架、次生代谢、分子伴侣/热激蛋白(HSPs)、ROS清除(氧化还原平衡)以及植物防卫反应等。虽然两个种群对干旱胁迫的生理响应是类似的，比如生长受抑制、光合下降、细胞膜受到伤害、渗透物质积累等，蛋白质组分析却显示出它们的蛋白表达谱存在明显差别。在生理和蛋白质组方面，种群和干旱之间均存在显著的互作效应。研究结果表明青杨的耐旱机制涉及脯氨酸、可溶糖等渗透物质的积累，以及一些抗旱相关蛋白的诱导有关，例如HSPs、抗氧化酶等，植物次生代谢的调节也在杨树的干旱适应过程中发挥了重要作用。与湿润种群相比，干旱种群表现出了更强的干旱适应能力，它具有更强的抗氧化酶系统，因而能更好地控制ROS的过量产生，减少ROS对光合器官的损害，在干旱下仍能维持较高的光合作用。 |
| 英文摘要 | Drought is one of the most important abiotic stress factors that limit plant growth and ecosystem productivity worldwide. Acclimation of plant to water deficit is the results of many different physiological and biochemical mechanisms. Poplars (Populus spp.) are fast-growing forest tree species and an important component of ecosystem. In this study, two contrasting populations of Populus cathayana Rehd. were used as model plants to investigate the adaptability to drought stress and differences between populations from dry and wet climate regions. Our results can provide theoretical evidence for the afforestation and prevention of desertification in the arid and semi-arid areas, and also can supply some useful clues for improving drought tolerance through genetic engineering or breeding through selection and utilization of existing forest genetic resources. The results are as follows:\n 1. The differences in the physiological responses of two contrasting P. cathayana populations to a progressive drought stress\n The growth, and the morphological and physiological properties of the two poplar populations were affected by water availability and these adaptative responses to drought stress depended on the time course and intensity of water deficit. Drought significantly inhibited plant growth and increased carotenoid contents and Car/Chl, and accumulated free proline and soluble sugar with the drought prolonged. In addition, antioxidant system including SOD and POD was also activated by drought stress. On the other hand, population differences in response to gradually increasing drought stress were also detected. Compared with the wet climate population, the dry climate population had lower shoot height and relative growth rate, but exhibited more efficient photoprotective systems such as carotenoid content, proline content and antioxidant system, as affected by drought stress than the wet climate population. Our data confirmed that the population from dry climate was more tolerant to progressive drought than the population from wet climate. \n 2. Comparative proteomic analyses on the responses of P. to the progressive drought stress\n A comparative proteomic method was used to investigate the adaptative responses of the two contrasting populations to the progressive drought stress. A total of 15 drought-responsive proteins were identified, whose functions are involved in regulation of transcription and translation, photosynthesis and carbon metabolism, secondary metabolism, HSPs/chaperones, cellular trasport and defense response. PAL was upregulated in both populations, which suggests its important roles in the adaptation to drought stress. Many HSPs were upregulated under drought, some of which were accumulated in both populations. The results indicate that HSPs play an important role in poplars’acclimation to drought stress. Compared with the wet climate population, the dry climate population possessed stronger regulation in secondary metabolism and photosynthetical aspects. Differences in regulation of drought-responsive proteins between the two populations may be one reason of different tolerance between populations. \n 3. Physiological and proteomic responses of the two contrasting P. cathayana populations to severe drought stress \n An integrated physiological and comparative proteomic analysis was used to investigate the responses of the two contrasting populations to severe drought stress. Drought stress significantly inhibited plant growth, decreased the relative water content (RWC), net photosynthetic rate and stomatal conductance of leaves, increased the relative electrolyte leakage and malondialdehyde (MDA) content, and, at the same time, accumulated soluble sugars and free proline in both populations tested. The population from the dry climate region exhibited stronger tolerance to drought stress compared with the wet climate population. A total of 59 spots showed defferential regulation under drought in the two populations. MALDI-TOF MS analysis resulted in the identification of 40 drought-responsive proteins. The functional categories of the identified proteins include the regulation of transcription and translation, photosynthesis and carbon metabolism, cytoskeleton, secondary metabolism, HSPs/chaperones, redox homeostasis/detoxification (ROS scavenging) and defense response. The interaction effects of the population and drought on the physiological traits and protein patterns were significant. The results suggest that poplars may tolerate drought stress by accumulating proline, sugars and several proteins related to drought-stress tolerance, such as HSPs and ROS scavenging enzymes. Regulation of secondary metabolism may also play important roles in poplars’ tolerance and acclimation to drought. |
| 中文关键词 | 青杨 ; 干旱胁迫 ; 差异蛋白质组学 ; 生态生理响应 ; 种群差异 |
| 英文关键词 | Populus cathayana Rehd drought stress comparative proteomics ecophysiological responses population differences |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 植物学 |
| 来源机构 | 中国科学院成都生物研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286627 |
| 推荐引用方式 GB/T 7714 | 肖向文. 青杨(Populus cathayana Rehd.)不同种群对干旱胁迫的生理响应及差异蛋白质组学研究[D]. 中国科学院成都生物研究所,2008. |
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