植物逆境信息传递研究进展

1、.,StressSignalinginPlants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,andTouch-InducedExpressionofCalmodulinandCalmodulin-RelatedGenesinArabidopsisCell60,357-364,1990,.,.,二,“刺激/逆境”“反应/应答”,.,1.形态、解剖,.,ClusterRoots,.,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

2、化机制(4)代谢调控(5)渗透调节(6)保水机制(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-AbundantProtein）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,.,CellularSinglingSystem?,.

3、,.,细胞信号系统,.,1Receptor/Sensor2.SecondMessenger3.ProteinKinase4.ProteinPhosphatase5.G-protein6.TranscriptionFactor7.Ubiquitination8.Methylation,SignalComponents,.,(1)Receptor/Sensor?,.,.,.,.,Receptortyrosinekinase,.,细胞内受体,.,ExamplesofPhytohormoneReceporandSignalTransduction,.,.,ABAReceptor,.,.,BRI1isa

4、membrane-associatedreceptorthatcyclesbetweentheplasmamembraneandendosomalcompartments.Theextracellularleucine-richrepeatdomainbindsbrassinosteroidsandtransducesthesignalthroughanintracellularkinasedomain.GTG1andGTG2areGPCR-typeGproteinsthatbindabscisicacid.TheyhaveinherentGTPaseactivitybutalsointera

5、ctwiththeonlycanonicalGsubunitinArabidopsis.PYR1/RCAR1isasolubleABAreceptorthatrepressesPP2CphosphatasesinthepresenceofABA.ThecytokininreceptorsCRE1,AHK2andAHK3areplasma-membrane-associatedandperceivecytokininthroughtheirextracellulardomains.Cytokininbindingtriggersaphosphorylationcascadethatisultim

6、atelytransmittedtoresponseregulatorsinthenucleus.Likethecytokininreceptors,theknownethylenereceptorsaretwo-componentregulators.AllfivereceptorsareactiveintheendoplasmicreticulumandtransmittheirsignalthroughacommondownstreamcomponentcalledCTR1.TIR1andCOI1areF-boxproteinsthatareintegralcomponentsofSCF

7、-typeE3ligasesandrecognizetheplanthormonesauxinandjasmonicacidrespectively.GID1isanuclear-localizedreceptorforgibberellins.GibberellinbindingtoGID1resultsintheenhanceddegradationDELLAproteins,.,.,自由基信号转导,.,.,(3)ReversibleProteinPhosphorylaton,.,.,.,.,(4)TranscriptionFactors,.,泛素(ubiquitin)是一种存在于大多数真

8、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8.5KD,Ubiquitination,.,.,.,四,细胞逆境信息传递举例介绍,.,盐胁迫和营养胁迫离子通道的调节,.,.,.,Figure12.FreezingandDroughtToleranceofthe35S:DREB1Aband35S:DREB1AcTransgenicPlants.Control,3-week-oldplantsgrowin

9、gundernormalconditions;freezingstress,plantsexposedtoatemperatureof-6Cfor2daysandreturnedto22Cfor5days;droughtstress,waterwithheldfromplantsfor2weeks.Percentagesofsurvivingplantsandnumbersofsurvivingplantspertotalnumberoftestedplantsareindicatedunderthephotographs.wt,wildtype.,.,HistoryofAbscisicAci

10、d(ABA)In1963,abscisicacidwasfirstidentifiedandcharacterizedbyFrederickAddicottandhisassociates.Theywerestudyingcompoundsresponsiblefortheabscissionoffruits(cotton).TwocompoundswereisolatedandcalledabscisinIandabscisinII.AbscisinIIispresentlycalledabscisicacid(ABA)(Addicot,1963).Twoothergroupsatabout

11、thesametimediscoveredthesamecompound.OnegroupheadedbyPhilipWareingwasstudyingbuddormancyinwoodyplants.TheothergroupledbyVanSteveninckwasstudyingabscissionofflowersandfruitsfromlupine.Plantphysiologistsagreedtocallthecompoundabscisicacid(SalisburyandRoss,1992).,.,.,SignalingFromWaterStressSensingtoAB

12、AAccumulation,.,五系统逆境信息传递,SystematicSignalinginPlantsorlong-distancesignaling,orintercellularsignaling,.,.,.,RootToShootSignalingUnderWaterDeficitCondition,.,.,.,.,.,pHSignaling,.,.,Image2.PseduColorRatio-imagesofpHindicatorBCECFinsunflowerstemandleafvascularsystempHindicatorBCECFwasloadedintothevas

13、cularsystemofanindividualsunflowerplantandimageswereacquiredasdescribedinMaterialandMethod.A,vascularsystematstembase;B,vascularsystematmidribofleafblade.,Image3.PseduColorRatio-imagesShowingtheEffectoftranspirationrateonleafapoplasticpHofCommelinacommunisL.pHindicatorNERFwasfirstloadedintointactpla

14、ntthroughrootsystem,thentheplantswereallowedtotranspirefor1hundereither35%or85%humidity,followingwhichfluorescenceimageswereacquiredasdescribedinMaterialandMethod.AandB,transpirationat35%humidity;CandD,transpirationat85%humidity.,.,Image3.PseduColorRatio-imagesShowingtheEffectoftranspirationrateonle

15、afapoplasticpHofCommelinacommunisL.pHindicatorNERFwasfirstloadedintointactplantthroughrootsystem,thentheplantswereallowedtotranspirefor1hundereither35%or85%humidity,followingwhichfluorescenceimageswereacquiredasdescribedinMaterialandMethod.AandB,transpirationat35%humidity;CandD,transpirationat85%hum

16、idity.,.,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,.,.,SystematicSignalingofLargeMolecularSignals,.,.,Fig.3.Newmodelforthephotoperiodresponseinplants.(A)ThepictureontheleftrepresentsthecurrentlyacceptedmodelforArabidopsis,inwhichlight-activatedCOovercomesthetemperature-dependentinhibitionfromFLCandinducestheexp

17、ressionofFTinthephloemcompanioncells.FTismovedtothephloemandchannelledtotheapicalmeristemwhereitbindstoFDandthecomplexisrecruitedintothenucleus.FTFDbindstothepromoterofSOC1andothermeristematicfloralintegrators,changingthevegetativedevelopmentalprogrammetotheABCprogramme,eventuallyproducingflowers.(B)ThemodelproposedhereincludesthatdepictedinA,butalsorecruitssimilarphotoperiodicmechanismstoregulateotherdevelopmentalprogrammesandbasicphysiologicalprocesses.Yellowarrowsrepresentexternalsignals:day/nighttra