Plant Hormone Signal transduction pathway 植物激素信號轉導通路

1、Plant Hormone Signal transduction pathway Talk OutlineGeneral introduction to cell signaling transduction pathways in plant.Different plant hormones and their physiological function in plants.Comparison between plant hormones and animal hormones action.Ways or approaches in studying plant hormone si

2、gnaling transduction pathways.Molecular mechanism of various plant hormone signal transduction pathways (a) ubiquitin-dependent protein degradation (negative regulator) (b) tow component system (phospho-relay). 6. Manipulation of plant growth and development with knowledge from plant hormone signal

3、transduction pathway. ex. Second green revolution. Analogy view of cell signaling transduction pathwayInput (command)KeyboardSignalperceptionEndogenous:phytohormoneExogenous:environmental cueCPU (Central Processing Unit)ChipSignal Transduction NetworkCompiling, Integration,processingOutput (performa

4、nce)PrinterSignal ResponseMorphogenesischange,Growth developmentdifferentiationVarious signaling transduction pathways in plantsCalcium (Ca+2) signaling (regulatory network)Lipid signaling transduction pathwayReactive oxygen species (ROS) signaling Nitric oxide (NO) signaling transduction pathwaySug

5、ar sensing responsive pathwayWounding-signal transduction pathway (plant-pathogen interaction)Light signaling responsive pathwayBiological oclock (circadian rhythm) regulatory pathwayDevelopment regulatory pathwaye. g. flowering (autonomous), lead, root, trichome formation root apical meristem (RAM)

6、 shoot apical meristem (SAM) formation polarity and cell cytoskeleton rearrangement Specific cell fate determination and differentiation(Xylem and phloem specification, root organization (patterning)Abiotic stress signaling pathways(salt, drought, heat, cold, metal, vernalization etc.)Plant hormone

7、signaling transduction(auxin, ethylene, cytokinin, gibberellin, abscisic acid, brasinosteroid, jasmonic acid etc.)Definition of plant hormoneThe word hormone is derived from the Greek verb meaning to excite.hormones are organic substances synthesized in one tissue and transported out where their pre

8、sence results in physiological responses ( not always true; may act at or close to synthesis site). They are required in minute amounts (10-6 to 10 -8M).3.Each hormone may result in multiple effects - the particular effect depending on a number of factors: (a) the presence of other hormones and the

9、presence of activator molecules ( calcium, sugars) (b) the amount of the hormone (dosage or concentration) (c) the sensitivity of that tissue to the hormone. (d) the condition of the plant itself is critical: what is the condition of the plant? its age? Site of action x developmental stage x concent

10、ration of hormone?Crosstalk and specificity? Chemical Structures of the Plant Hormonesplant hormones synthesis sites and their major functionsEffects of plant hormones on plant growth and developmentEmbryogenesis(Cell division, expansion, differentiation and cell death)SenescenceWhat is the differen

11、ce between plant hormones and animal hormones?Main approaches used to study plant hormone perception, signal transduction biosynthesis and responsesMolecular genetics approach hormone biosynthetic mutants vs. hormone insensitive mutants2. Biochemistry approach hormone binding protein (photo-affinity

12、 probe, affinity chromatography, immunopurification)3. Inhibitor approach kinase/phosphatase, G-protein, PKC etc inhibitors Science, 2001Dissect plant hormone signal transduction pathways by molecular genetic analysisChronological events and persons involved in identification of different hormone re

13、ceptors2007 (CHLH, GCR2)Summary of molecular components involved in plant hormone signaling transductionAuxin: TIR1: F-box protein (Ubiquitin conjugated ligase) PIN1 (pin-formed 1) Aux/IAA repressorEthylene: histidine kinase Raf-like kinase CTR1 Mitogen activated protein kinase cascadeCytokinin: pho

14、sphorelay (two-component system)4.Gibberellin: G protein and DELLA protein hexosamine (NAcGlu)5.Abscisic acid: PP2C protein, SnRK protein kinase FarnesylationBrasinosteroid: BRI1 (LRR-RLK)An overview of the ubiquitination process in plantsAnnals of Botany 99: 787-822 (2007)E1; UBA, ubiquitin activat

15、ing enzymeE2: UBC, ubiquitin conjugatingenzymeE3: ubiquitin protein ligaseRBX: ring-box proteinCUL: cullinCRL:cullin ring ligaseHECT: homologous to E6-AP COOH terminusRING: really interesting new gene protein domainSCF: SKP1-Cullin-F-boxSKP: S phase kinase associated proteinF-box: SKP/ASK interactio

16、n motif in cyclin FBiological significance of ubiquitin/proteosome system (UPS) in plantsUPS was involved in different processes of plant life, including organ initiation and embryogenesis patterning, light signalling , circadian clock regulation ,hormone production, perception and signal transducti

17、on, and in plant defence.2. The covalent attachment of ubiquitin to a substrate protein changes its fate. Notably, proteins typically tagged with a lysine48-linked polyubiquitin chain become substrates for degradation by the 26Sproteasome.Over 6 % (1,500 genes) of the predicted arabidopsis genome en

18、codes proteins involved in the UPS, and analyses of other plant genomes demonstrate a similar abundance of UPS-related genes. E1 (1); E2 (1); UEV (8); E3 (mast abundant): HECT (7); Ring (450); U-domain (61); cullin (11); F-box (700) BTB (80)Comparison between auxin and gibberellin signaling pathwayD

19、evelopment 133, 1857-1869 (2006)Crystal structure of the TIR1ASK1 complex with auxin and theIAA7 degron peptideauxin function as a molecular glue to enhanceTIR1substrate interactionsNature 446, 2007Phenotypes associated with the auxin and gibberellin receptor mutantsDevelopment 133, 1857-1869 (2006)

20、Brassinosteroid signaling pathwayDevelopment 133, 1857-1869 (2006)Phenotypes associated with the brassinosteroid, ethylene, cytokinin and abscisic acid receptor mutantsDevelopment 133, 1857-1869 (2006)Abscisic acid receptors: multiple signal-perception sitesAnnals of Botany 17, 2007FCA is a nuclear receptor for ABA controlin