strigolactones VS Auxin.docx
- 文档编号:14447834
- 上传时间:2023-06-23
- 格式:DOCX
- 页数:28
- 大小:36.04KB
strigolactones VS Auxin.docx
《strigolactones VS Auxin.docx》由会员分享,可在线阅读,更多相关《strigolactones VS Auxin.docx(28页珍藏版)》请在冰点文库上搜索。
strigolactonesVSAuxin
Agusti,J.,etal.(2011)."Strigolactonesignalingisrequiredforauxin-dependentstimulationofsecondarygrowthinplants."ProcNatlAcadSciUSA108(50):
20242-20247.
Longdistancecell-to-cellcommunicationiscriticalforthedevelopmentofmulticellularorganisms.Inthisrespect,plantsareespeciallydemandingastheyconstantlyintegrateenvironmentalinputstoadjustgrowthprocessestodifferentconditions.Oneexampleisthickeningofshootsandroots,alsodesignatedassecondarygrowth.Secondarygrowthismediatedbythevascularcambium,astemcell-liketissuewhosecell-proliferatingactivityisregulatedoveralongdistancebytheplanthormoneauxin.Howauxinsignalingisintegratedatthelevelofcambiumcellsandhowcambiumactivityiscoordinatedwithothergrowthprocessesarelargelyunknown.Here,weprovidephysiological,genetic,andpharmacologicalevidencethatstrigolactones(SLs),agroupofplanthormonesrecentlydescribedtobeinvolvedintherepressionofshootbranching,positivelyregulatecambialactivityandthatthisfunctionisconservedamongspecies.WeshowthatSLsignalinginthevascularcambiumitselfissufficientforcambiumstimulationandthatitinteractsstronglywiththeauxinsignalingpathway.Ourresultsprovideamodelofhowauxin-basedlong-distancesignalingistranslatedintocambiumactivityandsuggestthatSLsactasgeneralmodulatorsofplantgrowthformslinkingthecontrolofshootbranchingwiththethickeningofstemsandroots.
Beveridge,C.A.,etal.(2009)."Peahasitstendrilsinbranchingdiscoveriesspanningacenturyfromauxintostrigolactones."PlantPhysiol151(3):
985-990.
Beveridge,C.A.andJ.Kyozuka(2010)."Newgenesinthestrigolactone-relatedshootbranchingpathway."CurrOpinPlantBiol13
(1):
34-39.
Shootbranchingiscontrolledbytheformationandsubsequentoutgrowthofaxillarybudsintheaxilsofleaves.Axillarybudsareindeterminatestructuresthatcanbearrestedandawaitendogenousorenvironmentalcuesforoutgrowth.Amajorbreakthroughinthisareaofplantdevelopmenthasbeenthediscoverythataspecificgroupofterpenoidlactones,namedstrigolactones,candirectlyorindirectly,inhibitaxillarybudoutgrowth.Sincethatdiscovery,newbranchingmutantshavebeenidentifiedwithreducedstrigolactonelevelsorwhicharedefectiveinstrigolactoneregulationorresponse.DWARF27andDWARF14probablyactonstrigolactonebiosynthesisandstrigolactonemetabolismorsignaltransduction,respectively.Auxinsignalingmutantshavealsobeenusefulindemonstratingthatstrigolactonelevelsaremediatedbyaclassicalauxinsignaltransductionpathway.Thediscoveryandcharacterizationofthesemutantsisanimportantfirststeptowardunderstandingthemechanismsofstrigolactonebiosynthesisandsignalingandtheirimportanceinregulatingshootbranching.
Brewer,P.B.,etal.(2009)."StrigolactoneactsdownstreamofauxintoregulatebudoutgrowthinpeaandArabidopsis."PlantPhysiol150
(1):
482-493.
Duringthelastcentury,twokeyhypotheseshavebeenproposedtoexplainapicaldominanceinplants:
auxinpromotestheproductionofasecondmessengerthatmovesupintobudstorepresstheiroutgrowth,andauxinsaturationinthesteminhibitsauxintransportfrombuds,therebyinhibitingbudoutgrowth.Therecentdiscoveryofstrigolactoneasthenovelshoot-branchinginhibitorallowedustotestitsmodeofactioninrelationtothesehypotheses.Wefoundthatexogenouslyappliedstrigolactoneinhibitedbudoutgrowthinpea(Pisumsativum)evenwhenauxinwasdepletedafterdecapitation.WealsofoundthatstrigolactoneapplicationreducedbranchinginArabidopsis(Arabidopsisthaliana)auxinresponsemutants,suggestingthatauxinmayactthroughstrigolactonestofacilitateapicaldominance.Moreover,strigolactoneapplicationtotinybudsofmutantordecapitatedpeaplantsrapidlystoppedoutgrowth,incontrasttoapplyingN-1-naphthylphthalamicacid(NPA),anauxintransportinhibitor,whichsignificantlyslowedgrowthonlyafterseveraldays.WhereasstrigolactoneorNPAappliedtogrowingbudsreducedbudlength,onlyNPAblockedauxintransportinthebud.Wild-typeandstrigolactonebiosynthesismutantpeaandArabidopsisshootswerecapableofinstantlytransportingadditionalamountsofauxininexcessofendogenouslevels,contrarytopredictionsofauxintransportmodels.Thesedatasuggestthatstrigolactonedoesnotactprimarilybyaffectingauxintransportfrombuds.Rather,theprimaryrepressorofbudoutgrowthappearstobetheauxin-dependentproductionofstrigolactones.
Cazzonelli,C.I.,etal.(2009)."RegulationofcarotenoidcompositionandshootbranchinginArabidopsisbyachromatinmodifyinghistonemethyltransferase,SDG8."PlantCell21
(1):
39-53.
Carotenoidpigmentsarecriticalforplantsurvival,andcarotenoidcompositionistunedtothedevelopmentalstage,tissue,andtoenvironmentalstimuli.WereportthecloningoftheCAROTENOIDCHLOROPLASTREGULATORY1(CCR1)gene.Theccr1mutanthasincreasedshootbranchingandalteredcarotenoidcomposition,namely,reducedluteininleavesandaccumulationofcis-carotenesindark-grownseedlings.TheCCR1genewaspreviouslyisolatedasEARLYFLOWERINGINSHORTDAYSandencodesahistonemethyltransferase(SETDOMAINGROUP8)thatmethylateshistoneH3onLys4and/or36(H3K4andH3K36).ccr1plantsshowreducedtrimethyl-H3K4andincreaseddimethyl-H3K4surroundingtheCAROTENOIDISOMERASE(CRTISO)translationstartsite,whichcorrelateswithlowlevelsofCRTISOmRNA.Microarraysofccr1revealedthedownregulationof85genes,includingCRTISOandgenesassociatedwithsignalinganddevelopment,andupregulationofjust28genes.ThereductioninCRTISOtranscriptabundanceexplainsthealteredcarotenoidprofile.Thechangesinshootbranchingareadditivewithmoreaxillarybranchingmutants,butthealteredcarotenoidprofilemaypartiallyaffectshootbranching,potentiallybyperturbedbiosynthesisofthecarotenoidsubstratesofstrigolactones.TheseresultsareconsistentwithSDG8regulatingshootmeristemactivityandcarotenoidbiosynthesisbymodifyingthechromatinsurroundingkeygenes,includingCRTISO.Thus,theleveloflutein,themostabundantcarotenoidinhigherplantsthatiscriticalforphotosynthesisandphotoprotection,appearstoberegulatedbyachromatinmodifyingenzymeinArabidopsisthaliana.
Cheng,X.,etal.(2013)."Theinteractionbetweenstrigolactonesandotherplanthormonesintheregulationofplantdevelopment."FrontPlantSci4:
199.
Planthormonesaresmallmoleculesderivedfromvariousmetabolicpathwaysandareimportantregulatorsofplantdevelopment.Themostrecentlydiscoveredphytohormoneclasscomprisesthecarotenoid-derivedstrigolactones(SLs).Foralongtimethesecompoundswereonlyknowntobesecretedintotherhizospherewheretheyactassignalingcompounds,butnowweknowtheyarealsoactiveasendogenousplanthormonesandtheyhavebeeninthespotlighteversince.TheinitialdiscoverythatSLsareinvolvedintheinhibitionofaxillarybudoutgrowth,initiatedamultitudeofotherstudiesshowingthatSLsalsoplayaroleindefiningrootarchitecture,secondarygrowth,hypocotylelongation,andseedgermination,mostlyininteractionwithotherhormones.Theircoordinatedactionenablestheplanttorespondinanappropriatemannertoenvironmentalfactorssuchastemperature,shading,daylength,andnutrientavailability.Here,wewillreviewthecurrentknowledgeonthecrosstalkbetweenSLsandotherplanthormones-suchasauxin,cytokinin,abscisicacid(ABA),ethylene(ET),andgibberellins(GA)-duringdifferentphysiologicalprocesses.Wewillfurthermoretakeabird'seyeviewofhowthishormonalcrosstalkenablesplantstorespondtotheireverchangingenvironments.
Crawford,S.,etal.(2010)."Strigolactonesenhancecompetitionbetweenshootbranchesbydampeningauxintransport."Development137(17):
2905-2913.
Strigolactones(SLs),ortheirderivatives,wererecentlydemonstratedtoactasendogenousshootbranchinginhibitors,buttheirbiosynthesisandmechanismofactionarepoorlyunderstood.HereweshowthatthebranchingphenotypeofmutantsintheArabidopsisP450familymember,MAX1,canbefullyrescuedbystrigolactoneaddition,suggestingthatMAX1actsinSLsynthesis.WedemonstratethatSLsmodulatepolarauxintransporttocontrolbranchingandthatboththesyntheticSLGR24andendogenousSLsynthesissignificantlyreducethebasipetaltransportofasecondbranch-regulatinghormone,auxin.Importantly,GR24inhibitsbranchingonlyinthepresenceofauxininthemainstem,andenhancescompetitionbetweentwobranchesonacommonstem.Together,theseresultssupporttwocurrenthypotheses:
thatauxinmovingdownthemainsteminhibitsbranchactivitybypreventingtheestablishmentofauxintransportoutofaxillarybranches;andthatSLsactbydampeningauxintransport,thusenhancingcompetitionbetweenbranches.
daCosta,C.T.,etal.(2013)."Whenstressanddevelopmentgohandinhand:
mainhormonalcontrolsofadventitiousrootingincuttings."FrontPlantSci4:
133.
Adventitiousrooting(AR)isamultifactorialresponseleadingtonewrootsatthebaseofstemcuttings,andtheestablishmentofacompleteandautonomousplant.ARhastwomainphases:
(a)induction,witharequirementforhigherauxinconcentration;(b)formation,inhibitedbyhighauxinandinwhichanatomicalchangestakeplace.Thefirststagesofthisprocessinseveredorgansnecessarilyincludewoundingandwaterstressresponseswhichmaytriggerhormonalchangesthatcontributetoreprogramtargetcellsthatarecompetenttorespondtorootingstimuli.A
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- strigolactones VS Auxin