植物生理與分子生物學：Mechanisms of Cellular Polar Growth in Plant

1MechanismsofCellularPolarGrowthinPlant《植物生理與分子生物學》 PlantPhysiologyandMolecularBiology第四篇：生長發(fā)育 GrowthandDevelopment2《植物生理與分子生物學》 PlantPhysiologyandMolecularBiology第四篇：生長發(fā)育 GrowthandDevelopmentphysiology?

1.thebranchofbiologydealingwiththefunctionsandactivitiesoflivingorganismsandtheirparts,includingallphysicalandchemicalprocesses.2.theorganicprocessesorfunctionsinanorganismorinanyofitsparts.biology?

1.thescienceoflifeorlivingmatterinallitsformsandphenomena,esp.withreferencetoorigin,growth,reproduction,structure,andbehavior.2.thelivingorganismsofaregion:thebiologyofPennsylvania.3.thebiologicalphenomenacharacteristicofanorganismoragroupoforganisms:thebiologyofaworm.3《植物生理與分子生物學》 PlantPhysiologyandMolecularBiology第四篇：生長發(fā)育

Growth

andDevelopmentdevelopmentTheactofdeveloping.Thenaturalprogressionfromaprevious,simpler,orembryonicstagetoalater,morecomplex,oradultstage.Apurelybiologicalunfoldingofeventsinvolvedinanorganismchanginggraduallyfromasimpletoamorecomplexlevel.Patternformation.growthTheprocessofgrowing.Thenaturalprogressionfromaprevious,simpler,orembryonicstagetoalater,morecomplex,oradultstage.Anincrease,asinsize,number,value,orstrength;extensionorexpansion.4Theevolutionarystagesthatascientificdisciplineevolvesthrough,andthetypeofscientiststhataremostproductiveateachstage.Stage1.IntroducenewobjectsandphenomenaassubjectmatterforanewscientificdisciplineStage2.Developatoolboxofmethods&techniquesforthenewdisciplineStage3.GeneratemostofthespecificknowledgeandhighestnumberoforiginalresearchpublicationStage4.MaintainandpassonscientificknowledgegeneratedIsaacNewton,AntoineLavoisier,FrancisCrick,DmitryMendeleyevNobelPrizeWork,ingenuity&inventivenessre-describetheirsubjectmatterinthelanguagedevelopedatthesecondevolutionarystageandthiscreatesnewinsights,newanswersandnewquestions.Theleadersinthefieldtendtobetheneatest,mosthardworkinganddetailoriented.writeholisticcomprehensivereviewsandtextbook,coordinatingandhelpingtofocusfutureresearch.MechanismsofCellularPolarGrowthinPlantPollenTubeasanExample5Keywords:tipgrowth;signaltransduction;actincytoskeleton;smallGTPase;receptorkinase;phospholipids;Calciumions;axon;fungalhyphae;roothair;ROS6Imagefrom7CellGrowth

CellDivision

CellDeathIllustrationfromDiscoverScience,Scott,Foresman,&Co.,19938Howdoesacellgrow?非極性生長Non-polargrowth極性生長Polargrowth9PolarorNon-polar?LeafepidermalcellsRootcells8-cellembryoPolarityiseverywhere.Pollentube10Acellcangrow25cminlengthwithin24hours?50μm5000-foldoforiginalcelldiameter11MaizePollenTube12Whatispollen?AllergenTheWorldThemalegametophyteSporophyte(2N)Gametophytes(1N)MeiosisFertilizationLifeCycleofaFloweringPlant13Whatispollentube?StigmaStyleOvaryPistilHydrationGerminationPollentubegrowthMaturepollenGerminatedpollenPollenTransmittingtractAcarrierofspermcellsessentialforplantreproduction.14Howfastdoesapollentubegrow?Maizepollentubeinvivo: 10mm/hr 2500nm/sLilypollentubeinculture: 1mm/hr 250nm/sTomatopollentubeinvivo: 1.5mm/hr 400nm/sTomatopollentubeinvitro(PEGmedium)0.2mm/hr 60nm/sRoothair 0.1mm/hr 10-40nm/sXenopusneuronaxon 0.1mm/hr 20nm/stipgrowth15Whypollentubesgrowsofast?16TipGrowingCells花粉管神經(jīng)軸突根毛菌絲植物動物真菌17FeaturesofTipGrowth極端的極性生長快速的線性生長感受外界信號，調(diào)整生長方向頂端生長18Howapollentubefindsitswaythoughdifferentpistiltissuestotheovule?19TheMechanismofTipGrowthofPollenTube20ThebasicprocessofcelltipgrowthTargetedexocytosis21Theunderlyingsystemforcelltipgrowth22Theregulationnetworkofsignalingpathwayscalcium,phospholipids,smallGTPases,reactiveoxygenspecies(ROS),proteinkinases23IntercellularCommunicationPollentube-pistilinteractionPollentubeguidance24AbriefsummaryThebasicprocessofpollentubetipgrowth:targetedexocytosisThebasiccomponents:actindynamics,Ca2+gradient,membranetrafficking,cellwallTheregulatingnetworkofsignalingpathways:calcium,phospholipids,smallGTPases,reactiveoxygenspecies(ROS),proteinkinases,etcCell-cellcommunication:pollentube-pistilinteractionandpollentubeguidance25Howpollentubesgrow?

TheoldpiecesSecretoryvesicles(1965)Tip-to-basegradientofCa2+concentration(1975)Formationofcalloseplugs(1976)Theoutercellwall(pectin)andtheinnercellwall(calloseandcellulose)(1982)Cytoskeleton(1985)Cytoplsmicstreaming(before1989)26Anolddiagramofapollentubecell27Howpollentubesgrow?

ThenewprogressonthebasiccomponentsCa2+gradientActindynamicsExocytosisandendocytosisCellwallregulation28Ca2+gradientnMApollentubeloadedwithfura-2-dextranshowsaclearCa2+gradient.ApollentubemicroinjectedwithBCECF-dextranshowsanalkalineband29Ca2+andpHgradient30Ca2+

31RoleofCa2+gradientCalciumionsregulatecytoplasmicstreaming,facilitatemembranetraffickingandtheprocessofsecretion,controlcellwallassembly,participateinself-incompatibility,andinfluencetubeguidance.Calciumionsandprotonsclearlyplayamajorroleinpollentubegrowth,butwhataretheydoing?IonFluxesaroundthePollenTube3233Howpollentubesgrow?

ThenewprogressonthebasiccomponentsCa2+gradientActindynamicsExocytosisandendocytosisCellwallregulation34Actincytoskeleton35Acto-myosindrivescytoplasmicstreaming,including

thetransportofthesecretoryvesiclestothetip.36Actinpolymerizationpromotespollentubegrowththroughextensionofthecorticalactinfringe,whichservesasatracktotargetcellwallvesiclestopreferredexocytoticsites.37ActinBindingProteins383940Howpollentubesgrow?

ThenewprogressonthebasiccomponentsCa2+gradientActindynamicsExocytosisandendocytosisCellwallregulation41TwoquestionsHowdovesiclestransporttothetipafteractintransportation?Whypollentubesendocytosisatthetip?10umretrievaloftheexcesscellularmaterialsandinmembraneturnover42Theapexisthesiteofendocytosis,whileexocytosisoccursinthezoneadjacenttotheapicaldome.43Exocytosisandendocytosissites44Exocytosisandendocytosis45NewmodelOrganellemotilityinthepollentube46Regulationof

cytoplasmicstreaming4748Howpollentubesgrow?

ThenewprogressonthebasiccomponentsCa2+gradientActindynamicsExocytosisandendocytosisCellwallregulation49Tiphasnoinnerwall(calloseandcellulose)50Pectin51Pectinase52PectinmethylesteraseAsinglepectinlayer,lackingcalloseorcellulose,formsthetipcellwallandprovidesthisareawithsufficientrigortomaintainthecellularintegrity,ontheonehand,andwithplasticitytoallowdirectionaltubegrowth,ontheother.Duringthetubeelongationprocess,pectinsarepolymerized,aswellasmethylesterifiedandmodifiedwithsidechainswithintheGolgiapparatus,andtransportedintheGolgi-derivedvesiclestothepollentip.Followingvesicledischarge,homogalacturonan–alinearpolymercomposedof1,4-α-Dgalacturonicacidresidues,whichrepresentthemajorcomponentofpectin–isgraduallydeesterifiedbypectinmethylesterases(PMEs).Thedeesterificationofthepolygalacturonicacidchainconvertsthemethoxylgroupsintocarboxylgroups,exposingtheacidicresidueswhichthenarecross-linkedbycalciumions,creatinganewlayerofpectin.53PlantPMEs Calloseplug:evolutionaryinnovationoffloweringplantsDAPIandanilinebluedoublestainingshowinganormalpollentubehavecallosicwallsandperiodicallyformscalloseplugsinrear,keepingallthecytosolalongwiththespermandvegetativenuclearinthefront.growingtipCallose:β-1,3Glucan(JosephH.Williams,2008,PNAS)ThepollentubesofAngiospermscanachievefertilizationwithinshortertimethanthoseofGymnosperms,correlatingwiththeappearanceofcallosicwallsandcalloseplugs.5556ThehydrodynamicsmodeloftobaccopollentubegrowthFIG1.DepositionofcellwallmaterialisnotsufficienttocausecellulargrowthAtt=0s,thegrowthmediumcontaining10%sucroseisreplacedbymediumcontaining13%sucrose.ThehydrodynamicsmodeloftobaccopollentubegrowthFIG1.DepositionofcellwallmaterialisnotsufficienttocausecellulargrowthAtt=0s,thegrowthmediumcontaining10%sucroseisreplacedbymediumcontaining13%sucrose.62TheregulatingnetworkofsignalingpathwayssmallGTPasesphospholipidsreactiveoxygenspecies(ROS)proteinkinases,etc63TheregulatingnetworkofsignalingpathwayssmallGTPasesphospholipidsreactiveoxygenspecies(ROS)proteinkinases,etc64TheregulatingnetworkofsignalingpathwayssmallGTPases:smallguaninenucleotidebindingproteins–molecularswitchinsignaling65TheregulatingnetworkofsignalingpathwayssmallGTPases:ROPandRabphospholipidsreactiveoxygenspecies(ROS)proteinkinases,etc66ControlthePolarityofPollenTubeTipGrowthbyaRop/RacGTPaseWTCA-AtROP1GFP-AtROP1Ox-AtROP1Ox-AtROP1DN-AtROP1Lietal.199967AtRac768ROPpathway69DownstreamofROPRIC4promotesF-actinassembly,whereasRIC3activatesCa2+signalingthatleadstoF-actindisassembly.70UpstreamofROPAtomatoRopGEFisapartnerproteinofpollenreceptorkinasesLePRK1andLePRK2,namedKPP.RopGEFsinplantshaveanuniquedomainstructure(withaconservedPRONEdomain)InputGSTGST-CD1GST-CD235SMetT7-KPPPull-DowneGFP3h3h10mm10mm3h3h10mm10mmKPP-eGFP71MechanismofpollenreceptorkinaseregulatingRopGEFinArabidopsisthaliana72ROPpathwaylinkstoreceptorkinases73TheregulatingnetworkofsignalingpathwayssmallGTPases:ROPandRabphospholipidsreactiveoxygenspecies(ROS)proteinkinases,etc74Rab2GTPaseRegulatesVesicleTraffickingbetweentheEndoplasmicReticulumandtheGolgiBodies75Regulatevesiculartransport76TheregulatingnetworkofsignalingpathwayssmallGTPases:ROP/RacandRabphospholipids

reactiveoxygenspecies(ROS)proteinkinases,etc77PhospholipidsPIP2IP3+DAGPLCPADAGkinasePLD78PLC79PhospholipidspathwaylinktoRop8081PIP2,IP3,andphosphatidicacid8283848586TheregulatingnetworkofsignalingpathwayssmallGTPases:ROP/RacandRabphospholipidsreactiveoxygenspecies(ROS)proteinkinases,etc87Tip-localizedROSPMNADPHoxidaseO2O2-NADPHNADP+H+

NADP+,H+

HomologofmammalianneutrophilNADPHOxidasegp91phox,88TheregulatingnetworkofsignalingpathwayssmallGTPases:ROP/RacandRabphospholipidsreactiveoxygenspecies(ROS)proteinkinases,etcAGCKinases8990MultipleExtracellularSignalsChemocyanin(amemberoftheplantacyaninproteinfamilyofunknownfunction)andSCA(stigma/stylarcysteine-richadhesin)inLilyLTP(lipidtransferprotein)intobaccoLAT52,LeSTIG1,LeSHYintomatoTTSAGPintobaccoGABAinArabidopsisNitricoxide(NO)inLilyeATPinArabidopsisLUREs(synergidcells)inToreniafournieriLipids(cis-unsaturatedtriacylglycerides)intobacco91NitricOxideExtracellularATPandNO92Chemocyanin,asmallbasicproteinfromthelilystigma,inducespollentubechemotropism93PNASDecember23,2003vol.100no.2616125–16130GABA94Defensin-likepolypeptideLUREsarepollentubeattractantssecretedfromsynergidcells95PollentubesgravitatetowardLURE1protein(left,fluorescentgreen)expressedbysynergidcellsaroundT.fournieri’sembryosac(right).藍翅蝴蝶草Nature.2009Mar19;458(7236):357-6197Nogeneralconsensushasyetemergedofaunive