植物激素的作用機(jī)理研究

植物激素的作用機(jī)理研究---生長(zhǎng)素、油菜素內(nèi)酯激素是植物體內(nèi)合成的一系列天然化合物，以極微量的濃度引發(fā)生理反應(yīng)，在植物的生長(zhǎng)發(fā)育等多種生理過(guò)程以及器官發(fā)育、形態(tài)建成等方面起重要調(diào)節(jié)作用，也影響農(nóng)作物的產(chǎn)量、品質(zhì)和抗性等重要性狀。第一次綠色革命、雜交稻生產(chǎn)赤霉素(GA)產(chǎn)量提高(抗倒伏)

細(xì)胞分裂素穗粒數(shù)顯著增多油菜素內(nèi)酯株型結(jié)構(gòu)，光合能力蔬菜、瓜果的產(chǎn)量、抗性油菜素內(nèi)酯株型、根

生長(zhǎng)素植物激素的定義產(chǎn)生于植物體內(nèi)的特殊部位，是植物在正常發(fā)育過(guò)程中或特殊環(huán)境條件下的代謝產(chǎn)物；能從合成部位運(yùn)輸?shù)阶饔貌课?；不是營(yíng)養(yǎng)物質(zhì)，僅以很低的濃度產(chǎn)生各種特殊的調(diào)控作用。植物激素的種類植物激素的合成部位吲哚乙酸分生組織、種子細(xì)胞分裂素根尖赤霉素生長(zhǎng)的種子脫落酸、乙烯成熟、衰老和環(huán)境條件油菜素內(nèi)酯花粉，整株水平生長(zhǎng)素脫落酸細(xì)胞分裂素促進(jìn)細(xì)胞體積擴(kuò)大乙烯赤霉素莖伸長(zhǎng)生長(zhǎng)促進(jìn)細(xì)胞分裂促進(jìn)休眠促進(jìn)果實(shí)成熟油菜素內(nèi)酯促進(jìn)細(xì)胞延伸

作用廣泛相互作用、不同信號(hào)途徑間的交叉感知、信號(hào)轉(zhuǎn)導(dǎo)生長(zhǎng)素生長(zhǎng)素的生理功能生長(zhǎng)素的信號(hào)轉(zhuǎn)導(dǎo)ABP1、TIR1的發(fā)現(xiàn)及機(jī)理miRNA和生長(zhǎng)素生長(zhǎng)素的極性運(yùn)輸吲哚乙酸(IAA)的合成部位及含量細(xì)胞迅速分裂的部位,以嫩葉、莖端的分生組織及正在成長(zhǎng)的種子為主（在未成熟時(shí)最高，隨成熟進(jìn)度而逐漸減少）。含量視植物種類、器官及生長(zhǎng)發(fā)育階段而異。植物組織游離IAAIAA酯肽合IAA燕麥營(yíng)養(yǎng)組織16569燕麥穎果4407620未測(cè)到大麥穎果(已磨)40329未測(cè)到水稻穎果17032739未測(cè)到黍穎果3663198未測(cè)到小麥穎果123511未測(cè)到玉米營(yíng)養(yǎng)組織24528未測(cè)到玉米穎果500－100071600－78800未測(cè)到大豆種子450524菜豆種子2030136豌豆?fàn)I養(yǎng)組織35543豌豆種子93未測(cè)到202椰子胚乳液0905未測(cè)到蕎麥種子4012725向日葵種子30110未測(cè)到禾谷類豆科其他游離及結(jié)合態(tài)IAA在不同植物種類和部位的含量AuxinTryptophan-dependantbiosynthesisTryptophan-independentbiosynthesisPolartransportConjugationSignalingTropismsCelldivisionRootinitiationApicaldominanceLeafsenescenceFruitsettingandgrowthFloweringVasculardevelopmentFertilityChenetal.,2006Linetal.,2005生理作用多種激素的相互作用

赤霉素、乙烯、油菜素內(nèi)酯DifferentialeffectsofvariousauxinmoleculesIAA2,4-DNAAIBA10nM100nM100nM10mMWoodwardetal.,2005A,EandH:wildtype.B,C,FandG:ask1-1mutant,strongASK1-Line3,ASK1-Line14,ASK1-Line3.D:WTandstrongASK1RNAiline.IandQ(left):WTJtoM:ask1NtoP:ASKRNAilineQ(right)toT:ASK11

Arabidopsisauxin-relatedASKproteinZhaoetal.,1998ASK,CUL1/F-BoxadapterAuxinresistantReducedlateralrootsDwarfFloralabnormalitiesEmbryolethalAuxin-relatedSCF(Skp1-Cullin-Fboxprotein)componentsandSCF-regulatorygenesWoodwardetal.,2005PrimarystructureofproteinsinvolvedinauxinresponsesAuxin-bindingprotein1(ABP1)ABP1,firstdescribedfrommaize.ThefirstdetectionofABP1auxinbindingactivityincrudemembranepreparationsofetiolatedcoleoptiles.In1985,thebindingproteinwaspurifiedforthefirsttimeleadingtofunctionalstudiesofABP1,examinationofitscellbiologyanditsstructure.A2,4-Dmatrixwasalsousedtopurifypeachauxinbindingproteins,latershowntobemembersoftheproteinsuperfamilyknownasthegermins.Herteletal.,1972Rayetal.,1977Ray,1977Battetal.,1976Rayetal.,1977LoeblerandKlaembt,1985Ohmiyaetal.,1993Dunwelletal.,2000Cloningandexpressionoftwogenesencodingauxin-bindingproteinsfromtobacco,usingABP1cDNAclonesofmaizeandArabidopsisasprobes.PurificationschemeformaizeABP.:mainrouteforABPpurification;:alternativerouteforABPpurification;:routesforthepreparationoftheimmunoaffinitymatrices.Loebleretal.,1985;Watanabeetal.,1998TwomainstrategiesforABPisolationTheconserveddomainsofABP1Richardetal.,2003;Wooetal.,2001ABP1inorganizedcellelongationanddivisioninembryogenesisChenetal.,2001ABP1/ABP1abp1/abp1abp1/abp1ABP1/ABP1ABP1/ABP1abp1/abp1abp1/abp1abp1/abp1abp1/abp1abp1/abp1controlAnti-ABP1BY-2cellDivisionstageBY-2cellelongationstagecontrolAnti-ABP1Tianetal.,1995;Richardetal.,2003ABP1islocatedbothintheERandattheouterfaceoftheplasmamembranebuttheABP1inERdoesnotbindauxin.ABP1locatedattheplasmamembraneisinvolvedinthecontrolofearlyauxinelectrophysiologicalresponses.ABP1anddownstreamauxinresponsesCrosslinkofABP1andTIR1signalingpathwaysATPaseisrapidlystimulatedbyauxinandthereisalotofevidencethatABP1isthereceptorrelevantforthisprocess.Auxininducedde-novosynthesisofATPase.Christianetal.,2006InsensitiveresponsesRueggeretal.,1998;KepinskiandLeyser,2005TIR1,aF-boxprotein,isanauxinreceptorWTtir1InteractwithAux/IAAdomainIIpeptidesinanauxin-dependentmanner.RapidassociationanddissociationofTIR1–Aux/IAAcomplexes.ARFproteinbindsanAuxREpromoterelement.Underlow-auxinconditions,Aux/IAArepressorbindsARFviaheterodimerizationbetweenAux/IAAandARFdomainsIIIandIV.(B)AuxinpromotesAux/IAAdomainII-TIR1association,bringingtheAux/IAAproteintotheSCFTIR1complexforubiquitinationandsubsequentdestructionbythe26Sproteasome.TheactivatingARF,withaGln-rich(Q)middledomain,isthenfreedtopromoteauxin-inducedgeneexpression.WoodwardandBartel,2005Byinteractingwithspecificsubstrates,theF-boxproteinsconferspecificitytothedegradationmachinery.miRNA和auxinMechanisticandFunctionalModelsforRegulationbymiRNAsinPlantsInanimal,thesitesarein3’UTRandmultipleInplant,primarilyonlyonesitesinORF

miRNA通過(guò)調(diào)控生長(zhǎng)素作用影響生長(zhǎng)和發(fā)育

(葉、根、花發(fā)育的調(diào)控)miR165AS1/AS2MiRNAsinauxinsignaltransductionGuoetal.,

2005;Wangetal.,2005MiRNA164directsmRNAcleavageofNAC1todownregulateauxinsignalsMiRNA160-targetedARFs(ARF10,16)controlofrootcapformationSpecificationofleafpolarityviatheauxin-relatedtrans-actingsiRNApathwayTAS3targetsETTandARF4andexpressedintheadaxialdomain,andettas1ago7triplemutantsresembleas1.Garclaetal.,2006ABP1RBX1CUL1ASK1TIR1SCFTIR1E3RUB1/NEDD8CAND1CSNAXR1ECR1RCE1AUX/IAAAuxinCellelongationNucleus26SProteasomeAUX/IAAAUX/IAAdegradationARFMiRNAMG132Thepossiblemodelforauxinfunctions生長(zhǎng)素的極性運(yùn)輸與導(dǎo)管中生長(zhǎng)素運(yùn)輸不同(速率大、距離遠(yuǎn))；局限于胚芽鞘、幼莖及幼根的薄壁細(xì)胞；運(yùn)輸距離短，速率??；方向由細(xì)胞內(nèi)生長(zhǎng)素輸出載體的分別來(lái)確定；極性運(yùn)輸速率較擴(kuò)散大10倍作用；是一種主動(dòng)需能過(guò)程生長(zhǎng)素極性運(yùn)輸輸入載體輸出載體名稱相關(guān)功能PIN1維管系統(tǒng)的形成，花發(fā)育PIN2，3植物向性（光，重力等）PIN4根發(fā)育Liuetal.,1993AuxinandgynoeciummorphogenesisPin1mutantScience,1998擬南芥胚芽頂端形態(tài)建成中的幾個(gè)重要相關(guān)基因CUC1（CUP-SHAPEDCOTYLEDON1）CUC2（CUP-SHAPEDCOTYLEDON2）

PIN1

（PIN-FORMED1）→

MP（MONOPTEROS）生長(zhǎng)素信號(hào)傳導(dǎo)必須，突變使體軸混亂，子葉融合STM（SHOOTMERISTEMLESS）分生組織發(fā)育必須，突變使分生組織功能喪失，子葉部分融合PIN1在擬南芥胚芽頂端形態(tài)建成中的作用Pin2mutantPNAS,1998LateralrelocationofauxineffluxregulatorPIN3mediatestropisminArabidopsisPIN4同時(shí)具有調(diào)節(jié)生長(zhǎng)素的分布和細(xì)胞分化兩種功能，并介導(dǎo)生長(zhǎng)素儲(chǔ)留形成濃度梯度和根的細(xì)胞分化PIN4的抗體

PIN4mRNA

PIN4::GUSPIN4對(duì)胚和根中Auxin的分布及濃度的調(diào)節(jié)+10uMIAAPIN1localizationaffectedbycytoskeleton-depolymerizingdrugs.CytochalasinD(cytD)effectonBFAinhibitionofPIN1(green)cycling.a,Treatmentwith20mMcytDfor2h.b,Pre-treatmentwith20mMcytDfor15min,then50mMBFAand20mMCytDfor45min.c,Treatmentwith50mMBFAfor45minfollowedby90minwashingoutBFAwith20mMCytD.PIN1cyclingisactindependent.PIN1seemstotrafficalongtwodifferentpathways,dependingonthephaseofthecellcycle:Actin-dependentinterphasepathwaytoandfromtheplasmamemberaneµtube-dependentcytokinesispathwaytothecellplate.油菜素內(nèi)酯油菜素內(nèi)酯的生理功能油菜素內(nèi)酯的信號(hào)轉(zhuǎn)導(dǎo)分布到目前為止，已在裸子植物、被子植物、蕨類和綠藻等多達(dá)36種植物中檢測(cè)到40多種油菜素內(nèi)酯類固醇類物質(zhì)。植物地上部分的含量為ng/Kg-μg/Kg(鮮重組織)玉米的根中所檢測(cè)到的BR含量為0.3ng/g(鮮重組織)Keyenzymesdet2

dwf4油菜素內(nèi)酯的合成途徑在對(duì)各種秧苗和細(xì)胞培養(yǎng)的過(guò)程中，通過(guò)飼喂標(biāo)記中間物并用GC/MS分析代謝產(chǎn)物，證實(shí)了BR生物合成途徑中使鯊烯最終被轉(zhuǎn)化成為BL的大量反應(yīng)步驟。提高乙烯合成和偏上性生長(zhǎng)刺激苗的伸長(zhǎng)抑制根的生長(zhǎng)在組織培養(yǎng)中的作用農(nóng)業(yè)生產(chǎn)上的應(yīng)用擬南芥相關(guān)突變體Det2(de-etiolated2)Cpd(constitutivephotomorphogenesisanddwarf)Dwf4,dwf5(small,round,dark-greenleaves,andshortstems,pedicels,andpetiolesetc.)Dwf4Plantcell,1998;PNAS,1999BRI1:ThefirstBRreceptorclonedBRI1BRIL3OsBRI1SignalPeptideLeucineZipperLeucineRichRepeats70AAIslandTransmembraneDomainCytoplasmicKinasePP

?XYZCKOHOHHOHOHOOBKI1BRI1BRI1/BKI1heterodimerisafunctionalBRreceptorthatcanbindBRonthecellsurface.BES1AccumulatesintheNucleusinResponsetoBrassinosteroidstoRegulateGeneExpressionandPromoteStemElongationBRI1/BKI1BRBZR1/2BRsynthesisBRGrowthResponseCPDBIN2BZR1/2-pDegradationbyProteasomeBR-regulatedgeneexpressionZNF1BAK1TWD?HSP90?BSU1E3生長(zhǎng)素和油菜素內(nèi)酯間的相互作用及與其他激素、信號(hào)途徑間的相互作用生長(zhǎng)素和油菜素內(nèi)酯間的相互作用生長(zhǎng)素和油菜素內(nèi)酯與其他激素的相互作用生長(zhǎng)素和油菜素內(nèi)酯與其他信號(hào)途徑間的相互作用生長(zhǎng)素和油菜素內(nèi)酯間的相互作用

BRtreatmentleadstoalteredendogenousauxinlevelsand/orenhancedauxinsensitivity(Mandava1998;Sasse,1999,Nakamuraetal.,2003;Baoetal.,2004),suggestingpotentialcrosstalkbetweenBRandauxinsignalingpathways.BRandauxinsignalingpathwaysbothactivatetranscriptionofIAAbiosynthesisandauxinresponsivegenes(Nakamuraetal.,2003).BRspromotelateralrootinitiation/developmentbystimulatingacropetalauxintransport(Baoetal.,2004).BRconcentrationefficientlyinfluencedseedlingresponsestoauxinintermofhypocotylelongation,rootgrowthandlateralrootinitiation.(Jenniferetal.,2002)Thenode(s)ofintersectionbetweenauxinandBRpathwaysmustbedownstreamofBES1andAux/IAAsandupstreamofgeneexpression.Onelikelymechanismisviaregulationoftranscriptionalcomplexes,suchasthosecontainingtheARFs.AuxinandBRsignalsarelikelyintegratedonpromotersofsharedtargetgenesGenomicEvidencefortheBR-AuxinInterplayRelativeproportionofBR-andauxin-responsivegenes.(Jenniferetal.,2002)IncreasedbasipetalauxintransportTropismsBRROP2PossibleModelPIN2Actinassembly/re-assembly?OtherPINsPlantgrowthHypocotylbendingLateralrootdevelopment激素間的相互作用激素在合成、代謝等方面的相互調(diào)控；不同激素通過(guò)在信號(hào)途徑、下游調(diào)控基因以及運(yùn)輸、分布等方面的交叉共同調(diào)控植物發(fā)育。植物激素間的相互作用生長(zhǎng)素細(xì)胞分裂素細(xì)胞生長(zhǎng)分化、胚胎形成相互促進(jìn)生長(zhǎng)素細(xì)胞分裂素植物頂端優(yōu)勢(shì)生長(zhǎng)素乙烯葉片脫落拮抗作用生長(zhǎng)素脫落酸赤霉素乙烯通過(guò)影響其他激素的合成、運(yùn)輸或代謝而改變其濃度生長(zhǎng)素促進(jìn)乙烯合成細(xì)胞分裂素＋細(xì)胞分裂素抑制生長(zhǎng)素結(jié)合態(tài)形成，提高生長(zhǎng)素濃度乙烯抑制生長(zhǎng)素運(yùn)輸及代謝赤霉素促進(jìn)生長(zhǎng)素合成油菜素內(nèi)酯促進(jìn)生長(zhǎng)素運(yùn)輸Cross-talkbetweenauxinandotherhormonesWTalh1AuxinEthyleneEthyleneeffectonhypocotylelongationandbendingaremainlymediatedthroughauxin,mainlybyalteredpolarauxintransport.CytokininBrassinosteroids?AbscisicAcidGerminationRootdevelopment激素與其他信號(hào)途徑間的交叉

G蛋白第二信使途徑糖信號(hào)等(SoniaGazzarrinandPeterMccourt,2003)Cross-talkbetweenAuxinandothersignalsCross-talkbetweenAuxinandothersignalsAuxinOtherhormonesLightsignalingG-prosignalingOthersMAPKsignalingSugarsignalingPhosphatidylinositolsignalingIns(1,4)P2Ins(1,3,4,5,6)P5IPPasemyo-inositolCDP-DGPIPIPPIP2DAGIns(1,4,5)P3PISPI4KPIPKPLCVacuoleCa2+Ca2+ProteinkinasecascadeABA,Auxin,GA通過(guò)第二信使控制植物反應(yīng)IPPaseAuxin合成葉脈發(fā)育PLDζ

Auxin信號(hào)根發(fā)育PLDα1

ABI1ABA信號(hào)激素受體、結(jié)合蛋白的功能、定位油菜素內(nèi)酯：BRI1，質(zhì)膜生長(zhǎng)素：TIR1，核內(nèi)TIR1doesnothaveamonopolyonthetitleauxinreceptor.Indeed,ifitdid,onemightexpectasevereorlethalphenotypeinhomozygousloss-of-functionmutantsbutthisisnotthecase.Rueggeretal.,1998ThepHatwhichhigh-affinitybindinginthenucleus(pH7.2–7.5forTIR1).Atthecellsurface(pH5.0–6.0forABP1).Therefore,thebindingaffinitiesandselectivitiesoftheSCFTIR1complexandofABP1areconsistentwiththepropertiesanticipatedfo