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 transdu
3、ction 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(performance)PrinterSig
4、nal 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 pathwaySugar sensing responsive
5、 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)shoot apical meristem(SAM)forma
6、tion 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 signaling transduction(auxin,ethylene,cyt
7、okinin,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 presence results in physiological responses(not al
8、ways 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 presence of activator molecules(calcium,sugars)(b)the amo
9、unt 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 concentration of hormone?Crosstalk and specificity?Chemical Structures of the
10、 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 difference between plant hormones and animal hormones?Main approaches used to stu
11、dy plant hormone perception,signal transduction biosynthesis and responsesMolecular genetics approach hormone biosynthetic mutants vs.hormone insensitive mutants2.Biochemistry approach hormone binding protein (photo-affinity probe,affinity chromatography,immunopurification)3.Inhibitor approach kinas
12、e/phosphatase,G-protein,PKC etc inhibitors Science,2019Dissect plant hormone signal transduction pathways by molecular genetic analysisChronological events and persons involved in identification of different hormone receptors2019(CHLH,GCR2)Summary of molecular components involved in plant hormone si
13、gnaling 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:phosphorelay(two-component system)4.Gibberellin:G protein and DELLA protein hexosamine(NAcGlu)5
14、.Abscisic acid:PP2C protein,SnRK protein kinase FarnesylationBrasinosteroid:BRI1(LRR-RLK)An overview of the ubiquitination process in plantsAnnals of Botany 99:787-822(2019)E1;UBA,ubiquitin activating enzymeE2:UBC,ubiquitin conjugatingenzymeE3:ubiquitin protein ligaseRBX:ring-box proteinCUL:cullinCR
15、L: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 interaction motif in cyclin FBiological significance of ubiquitin/proteosome system(UPS)in plantsUPS was involved in differ
16、ent processes of plant life,including organ initiation and embryogenesis patterning,light signalling,circadian clock regulation,hormone production,perception and signal transduction,and in plant defence.2.The covalent attachment of ubiquitin to a substrate protein changes its fate.Notably,proteins t
17、ypically tagged with a lysine48-linked polyubiquitin chain become substrates for degradation by the 26Sproteasome.Over 6%(1,500 genes)of the predicted arabidopsis genome encodes proteins involved in the UPS,and analyses of other plant genomes demonstrate a similar abundance of UPS-related genes.E1(1
18、);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 pathwayDevelopment 133,1857-1869(2019)Crystal structure of the TIR1ASK1 complex with auxin and theIAA7 degron peptideauxin function as a molecular glue to en
19、hanceTIR1substrate interactionsNature 446,2019Phenotypes associated with the auxin and gibberellin receptor mutantsDevelopment 133,1857-1869(2019)Brassinosteroid signaling pathwayDevelopment 133,1857-1869(2019)Phenotypes associated with the brassinosteroid,ethylene,cytokinin and abscisic acid recept
20、or mutantsDevelopment 133,1857-1869(2019)Abscisic acid receptors:multiple signal-perception sitesAnnals of Botany 17,2019FCA is a nuclear receptor for ABA controling flowering.ABAR/CHLH is a plastid receptor for ABA controlling major ABA response.GCR2 is a plasma membrane receptor for ABA controllin
21、g ABA physiological response.“ABA-binding pocket”Major transcription factors and cis-regulatory elements involved in abscisic acid ABA-dependent stress responsesPhysiologia Plantarum 126:519527.2019Composition of the transmembrane phytohormone receptorsDevelopment 133,1857-1869(2019)Ethylene and cytokininsignaling pathways(two component system)Development 133,1857-1869(2019)Genetic manipulation of GAmetabolism or signal transduction pathway?(second Green Revolution?)Thanks for your attention!Thanks for your attention!
