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1、Stress Signaling in Plants 贾文锁 中国农业大学,一 “感知”和“反应” 生物生存和发展的基础,敏感植物,一般植物,Rain,Wind, and Touch-Induced Expression of Calmodulin and Calmodulin-Related Genes in ArabidopsisCell 60,357-364,1990,二,“刺激/逆境”“反应/应答”,1.形态、解剖,Cluster Roots,2.整体生理,生命周期短命菊,3.细胞生理及生化,(1) 解毒机制 (2)自由基清除 (3)区隔化机制 (4)代谢调控 (5)渗透调节 (6)保
2、水机制 (7)结构避损机制 (8)修复机制,渗透调节,脯氨酸 甜菜碱 山梨醇 海藻糖,保护酶系统与自由基清楚剂 游离的带有不成对电子的分子、原子或离子,区隔化机制,结构避损机制,功能蛋白 代谢调控蛋白 （渗透调控系统，保护酶） Lea 蛋白（Late-Embryogenesis-Abundant Protein） 通道蛋白：离子通道，水通道 热击蛋白：亲水，保护酶活 损伤修复蛋白 调节蛋白 信号蛋白 转录因子,基因,功能蛋白基因 调节蛋白基因,应答反应与伤害反应,三,信号系统与信号组分,Cellular Singling System ?,细胞信号系统,1 Receptor /Sensor 2
3、. Second Messenger 3. Protein Kinase 4. Protein Phosphatase 5. G-protein 6. Transcription Factor 7. Ubiquitination 8. Methylation,Signal Components,(1) Receptor /Sensor?,Receptor tyrosine kinase,细胞内受体,Examples of Phytohormone Recepor and Signal Transduction,ABA Receptor,BRI1 is a membrane-associated
4、 receptor that cycles between the plasma membrane and endosomal compartments. The extracellular leucine-rich repeat domain binds brassinosteroids and transduces the signal through an intracellular kinase domain. GTG1 and GTG2 are GPCR-type G proteins that bind abscisic acid. They have inherent GTPas
5、e activity but also interact with the only canonical G subunit in Arabidopsis. PYR1/RCAR1 is a soluble ABA receptor that represses PP2C phosphatases in the presence of ABA. The cytokinin receptors CRE1, AHK2 and AHK3 are plasma-membrane-associated and perceive cytokinin through their extracellular d
6、omains. Cytokinin binding triggers a phosphorylation cascade that is ultimately transmitted to response regulators in the nucleus. Like the cytokinin receptors, the known ethylene receptors are two-component regulators. All five receptors are active in the endoplasmic reticulum and transmit their si
7、gnal through a common downstream component called CTR1. TIR1 and COI1 are F-box proteins that are integral components of SCF-type E3 ligases and recognize the plant hormones auxin and jasmonic acid respectively. GID1 is a nuclear-localized receptor for gibberellins. Gibberellin binding toGID1 result
8、s in the enhanced degradation DELLA proteins,自由基信号转导,(3) Reversible Protein Phosphorylaton,(4) Transcription Factors,泛素(ubiquitin)是一种存在于大多数真核细胞中的小蛋白。它的主要功能是标记需要分解掉的蛋白质，使其被水解。当附有泛素的蛋白质移动到桶状的蛋白酶的时候，蛋白酶就会将该蛋白质水解。也可能被转移到细胞或细胞外的特定部位，也有可能导致靶蛋白的功能发生变化。泛素76个氨基酸组成，分子量大约8.5 KD,Ubiquitination,四,细胞逆境信息传递 举例介绍,盐
9、胁迫和营养胁迫离子通道的调节,Figure 12. Freezing and Drought Tolerance of the 35S:DREB1Ab and 35S:DREB1Ac Transgenic Plants.Control, 3-week-old plants growing under normal conditions; freezing stress, plants exposed to a temperature of -6C for 2 days and returned to 22C for 5 days; drought stress, water withheld
10、from plants for 2 weeks. Percentages of surviving plants and numbers of surviving plants per total number of tested plants are indicated under the photographs. wt, wild type.,History of Abscisic Acid (ABA) In 1963, abscisic acid was first identified and characterized by Frederick Addicott and his as
11、sociates. They were studying compounds responsible for the abscission of fruits (cotton). Two compounds were isolated and called abscisin I and abscisin II. Abscisin II is presently called abscisic acid (ABA)(Addicot, 1963). Two other groups at about the same time discovered the same compound. One g
12、roup headed by Philip Wareing was studying bud dormancy in woody plants. The other group led by Van Steveninck was studying abscission of flowers and fruits from lupine. Plant physiologists agreed to call the compound abscisic acid (Salisbury and Ross, 1992).,Signaling From Water Stress Sensing to A
13、BA Accumulation,五 系统逆境信息传递,Systematic Signaling in Plants or long-distance signaling, or intercellular signaling,Root To Shoot Signaling Under Water Deficit Condition,pH Signaling,Image 2. Psedu Color Ratio-images of pH indicator BCECF in sunflower stem and leaf vascular system pH indicator BCECF wa
14、s loaded into the vascular system of an individual sunflower plant and images were acquired as described in Material and Method. A, vascular system at stem base; B, vascular system at midrib of leaf blade.,Image 3. Psedu Color Ratio-images Showing the Effect of transpiration rate on leaf apoplastic
15、pH of Commelina communis L. pH indicator NERF was first loaded into intact plant through root system, then the plants were allowed to transpire for 1 h under either 35% or 85% humidity, following which fluorescence images were acquired as described in Material and Method . A and B, transpiration at
16、35% humidity; C and D, transpiration at 85 % humidity.,Image 3. Psedu Color Ratio-images Showing the Effect of transpiration rate on leaf apoplastic pH of Commelina communis L. pH indicator NERF was first loaded into intact plant through root system, then the plants were allowed to transpire for 1 h
17、 under either 35% or 85% humidity, following which fluorescence images were acquired as described in Material and Method . A and B, transpiration at 35% humidity; C and D, transpiration at 85 % humidity.,干旱条件下ABA可以作为长距离传递信号使植物产生系统抗逆性,Systematic Signaling of Large Molecular Signals,Fig. 3. New model
18、for the photoperiod response in plants. (A) The picture on the left represents the currently accepted model for Arabidopsis, in which light-activated CO overcomes the temperature-dependent inhibition from FLC and induces the expression of FT in the phloem companion cells. FT is moved to the phloem a
19、nd channelled to the apical meristem where it binds to FD and the complex is recruited into the nucleus. FTFD binds to the promoter of SOC1 and other meristematic floral integrators, changing the vegetative developmental programme to the ABC programme, eventually producing flowers. (B) The model pro
20、posed here includes that depicted in A, but also recruits similar photoperiodic mechanisms to regulate other developmental programmes and basic physiological processes. Yellow arrows represent external signals: day/night transition; circadian clock; light quality; and a metabolic signal represented by a fertilizer bottle. Black arrows indicate some of the outputs of the photoperiodic response.,一些值得深入思考的问题,“逆境应答反应” = “抗逆反应”吗? “逆境应答基因” = “抗逆基因”吗? “应答基因”中真的存在关键的基因吗? “关键的抗逆基因”一定是”逆境应答基因”吗? “逆境应答反应”的本质是什么? 是为抗逆而独立存在的吗?,功能解析3,