Jasmonates An Update on Biosynthesis Signal Transd

INVITEDREVIEWJasmonates:AnUpdateonBiosynthesis,SignalTransductionandActioninPlantStressResponse,GrowthandDevelopmentC.WASTERNACK*DepartmentofNaturalProductBiotechnology,Leibniz-InstituteofPlantBiochemistry,Weinberg3,D-06120Halle(Saale),GermanyReceived:30December2006Returnedforrevision:8February2007Accepted:15February2007†BackgroundJasmonatesareubiquitouslyoccurringlipid-derivedcompoundswithsignalfunctionsinplantresponsestoabioticandbioticstresses,aswellasinplantgrowthanddevelopment.Jasmonicacidanditsvariousmetabolitesaremembersoftheoxylipinfamily.Manyofthemaltergeneexpressionpositivelyornegativelyinaregulatorynetworkwithsynergisticandantagonisticeffectsinrelationtootherplanthormonessuchassalicy-late,auxin,ethyleneandabscisicacid.†ScopeThisreviewsummarizesbiosynthesisandsignaltransductionofjasmonateswithemphasisonnewfindingsinrelationtoenzymes,theircrystalstructure,newcompoundsdetectedintheoxylipinandjasmonatefamilies,andnewlyfoundfunctions.†ConclusionsCrystalstructureofenzymesinjasmonatebiosynthesis,increasingnumberofjasmonatemetabolitesandnewlyidentifiedcomponentsofthejasmonatesignal-transductionpathway,includingspecificallyactingtran-scriptionfactors,haveledtonewinsightsintojasmonateaction,butitsreceptor(s)is/arestillmissing,incontrasttoallotherplanthormones.Keywords:Oxylipins,jasmonicacid,jasmonatemetabolites,enzymesinbiosynthesisandmetabolism,signalfunction.INTRODUCTIONInrecentyears,largescaleanalysesofgenesequences(genomics),expression(transcriptomics),proteinpatterns(proteomics),metaboliteprofiles(metabolomics)andlipidcompounds(lipidomics)havebeenperformedandremainthefocusofmanystudies.Thetremendousamountofaccu-mulateddatahasledtonewinsightsintohowplantsrespondtobioticorabioticstressandhowagrowthanddevelopmentalprogramtakesplaceintheplantlifecycle.Anessentiallinkwithinsuchprogrammingisprovidedbysmallmolecules,suchasplanthormones.Amongthese,jasmonateshaveattractedmuchinterestoverthelasttwodecades.In1962,jasmonicacidmethylester(JAME;seeAppendixforalistofabbreviations)wasisolatedforthefirsttimefromtheessentialoilofJasminumgrandiflorum(Demoleetal.,1962).ThefirstphysiologicaleffectsofJAME,however,anditsfreeacid(JA)wereonlyobservedtwodecadeslater.In1980,Ueda’sgroupinOsaka,Japan,describedasenescence-promotingeffectofJA,andSembdner’sgroupinHalle,Germany,isolatedandcharac-terizedthesecompoundsasgrowthinhibitors(UedaandKato,1980;Datheetal.,1981).InhibitionofrootgrowthbecamethemostprominentassayforscreeningofmutantsaffectedinrespectofJAsignalling.Thebiosyn-thesisofJAwaselucidatedbyVickandZimmermann(1984).ThefunctionalanalysisofthemodeofactionwasinitiatedbytheobservationinParthier’sgroupinHallethatapplicationofJAoritsmethylestertobarleyleavesleadstoanalteredproteinpattern.Thesynthesisofabun-dantlyaccumulatingproteins,so-calledjasmonate-inducedproteins(JIPs)anddegradationofhousekeepingproteinssuchasRubiscoweredescribedforthefirsttimein1987(Weidhaseetal.,1987a,b).In1990,anotherdra-maticalterationofgeneexpressionbyJAMEwasobservedintomatoplants(FarmerandRyan,1990).Here,aprotein-aseinhibitor(PIN2)wasfoundtoaccumulateuponwound-ing(suchasthatcausedbyherbivoreattack)orbytreatmentwithairborneJAME.Subsequently,JA-inducedalterationofgeneexpressionandmetabolitepatternsbecamethefocusofstudiesexaminingaccumulationofvegetativestorageproteinsinStaswick’sgroup(Staswicketal.,1992)andalkaloidsinZenk’sgroup(Gundlachetal.,1992).Inthelattercase,anendogenousriseofJAwasdemonstrateduponelicitationofcellsuspensioncultures,thusindicatingJAasaputativesignalbetweentheexternalstimulusandtheresponsebycellsofalkaloidformation.OtherbreakthroughswerethefirstcloningofaJAbiosyn-theticenzyme,alleneoxidesynthase(AOS)inBrash’slab(Songetal.,1993)andisolationofthefirstJA-insensitivemutantinTurner’slab(Feysetal.,1994).Thismutantwasscreenedbyuseofcoronatine,abacterialtoxinwithstructuralandfunctionalsimilaritytoJA(coronatine-insensitive1,coi1).Fouryearslater,Turner’slabwereabletoclonethecorrespondinggene.COI1codesforanF-boxprotein,whichispartoftheubiquitin-mediatedpro-teasomepathway(Xieetal.,1998).Inthesameyear,thecorrespondingF-boxproteininauxinsignaling,TIR1wascloned.Consequently,mucheffortwasspentintryingtounderstandhormonesignallinginmoleculartermsandthisledtotheidentificationofTIR1asoneoftheauxinreceptors*[e-mail]#TheAuthor2007.PublishedbyOxfordUniversityPressonbehalfoftheAnnalsofBotanyCompany.Allrightsreserved.ForPermissions,pleaseemail:[e-mail]1–17,2007doi:10.1093/aob/mcm079,availableonlineat(Dharmasirietal.,2005;KepinskiandLeyser,2005).TheJAreceptor,however,isstillunknown.OtherimportantstepsinunderstandingtheactionofjasmonatesweretheidentificationofmutantsaffectedinJA-biosynthesis(cf.Turneretal.,2002),theidentificationofthefirsttran-scriptionfactorsregulatingJA-responsivegeneexpressionbyMemelink’sgroup(vanderFitsandMemelink,2001),theproofthatfattyacidb-oxidationactsinJAbiosynthesis(Lietal.,2005),andthecloningofJAaminoacidconjugatesynthase(JAR1)byStaswick’s