植物响应冻融胁迫的机制研究 
张旭东 
学位类型博士
导师李唯奇 
2010-11
学位授予单位中国科学院研究生院
学位专业植物学
摘要低温是影响植物生长的主要逆境因子之一,不仅限制植物的地理分布,而且通过缩短植物的生长季节减少植物产量,每年给全球农作物带来数十亿美元的经济损失。自然界植物响应低温胁迫分为三个阶段:冷驯、冻、融,目前对低温胁迫分子机制的大量深入研究主要是集中在零上低温阶段,对于零下低温冻的阶段研究较少,从零下低温回升至零上温度的融这一阶段的研究更是鲜见报导。本实验室前期研究结果提示植物对冻融的响应是复杂且重要的,并非仅仅是对冻害的被动响应,也有一些关键的主动响应作用,在基因表达、信号通路和膜脂变化上都有特殊的规律,这些规律的深入研究有助于认识植物对低温胁迫的响应和提高植物的抗逆性。本文以模式植物拟南芥(Arabidopsis thaliana)及其具有优越抗逆性状的近缘种小盐芥(Thellungiella halophlia)为研究对象,在对植物抗冻性起关键作用的基因表达调控、信号传导通路和膜脂分子变化三个层次上研究了植物响应冻融胁迫的机制,得到以下五方面结果:第一,获得拟南芥在冻融胁迫中转录组水平的响应,并鉴定3个与冻融过程相关的功能基因;第二,得到冻融过程差异表达基因中高频出现的顺式元件,验证其中个别元件在冻融过程的实际结合作用,并进一步预测了可能响应冻融胁迫的新元件;第三,初步了解microRNA对拟南芥响应冻融胁迫的调控,得到36个冻融过程中可能受到microRNA调控的功能基因;第四,鉴定了植物激素Auxin对拟南芥响应冻融胁迫的负调控作用;第五,揭示了抗冻植物小盐芥在冻融胁迫中膜脂组成变化规律。
资助项目Cold stress is one of the major environmental factors that adversely influence plants growth. Cold stress not only limits plants geographic distribution, but also reduces plants yield by shortening growing season, which brought billions of dollars economic losses for global crop. In nature, responses of overwintering plants to low temperature can be divided into three distinct phases: cold acclimation (CA), freezing, and post-freezing recovery (PFR). Until now, plenty intensive study about molecular mechanism of cold stress mainly focused on the above-zero low temperature phase. However, the studies on the freezing phase below zero and the following PFR phase with temperature going up to above-zero were rare. The previous research form our lab hinted that the responses of plants to freezing and PFR were complex and important. Except for passive reflection, there were also crucial active responses during this process. Several special rules were presented at the different levels including gene expression, signal transduction and membrane lipids changes, and fully understanding these rules would be helpful for us to explore the responses of plants to low temperature and then proceed to improve the freezing resistance of plants. In the present study, the mechanisms of respond to freezing and PFR of model plant Arabidopsis thaliana and its close relative Thellungiella halophlia that with extreme tolerance to abiotic stresses were carried out, including regulation of gene expression, signal transduction pathway and membrane lipids changes three levels which were essential for the freezing resistance of plants. Ground on these work, we obtained results from the following five aspects. First, the complete picture of A. thaliana responding to freezing and PFR at transcriptome level was elaborated and three functional genes closely related to the phases were identified. Second, the cis-elements with high frequent presence in differentially expressed genes were elucidated, and the practical binding of one elements among them was experimental verified during freezing and PFR. Moreover, we predicted the new elements which would respond to freezing and PFR. Third, the regulation of freezing stress by microRNA in A. thaliana was preliminarily investigated and 36 functional genes possibly regulated by miRNA during freezing and PFR were gained. Fourth, the negative effect of phytohormone Auxin on A. thaliana subjected to freezing stress was identified. Fifth, for the freezing-resistant plant T. halophlia, the rules of membrane lipids composition changes under freezing stress were uncovered.
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16024
专题昆明植物所硕博研究生毕业学位论文
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张旭东 . 植物响应冻融胁迫的机制研究 [D]. 中国科学院研究生院,2010.
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