Ghd7张启发 NG

NaturalvariationinGhd7isanimportantregulatorofheadingdateandyieldpotentialinriceWeiyaXue1,2,YongzhongXing1,2,XiaoyuWeng1,YuZhao1,WeijiangTang1,LeiWang1,HongjuZhou1,SibinYu1,CaiguoXu1,XianghuaLi1&QifaZhang1Yieldpotential,plantheightandheadingdatearethreeclassesoftraitsthatdeterminetheproductivityofmanycropplants.Hereweshowthatthequantitativetraitlocus(QTL)Ghd7,isolatedfromanelitericehybridandencodingaCCTdomainprotein,hasmajoreffectsonanarrayoftraitsinrice,includingnumberofgrainsperpanicle,plantheightandheadingdate.EnhancedexpressionofGhd7underlong-dayconditionsdelaysheadingandincreasesplantheightandpaniclesize.Naturalmutantswithreducedfunctionenablericetobecultivatedintemperateandcoolerregions.Thus,Ghd7hasplayedcrucialrolesforincreasingproductivityandadaptabilityofriceglobally.Cerealgrainsaretheprimarysourceoffoodandanimalfeedglobally.Increasinggrainyieldofcerealshasbeenamongthemostimportantgoalsofcropproductionandplantscienceresearch.Toachievehighyield,plantsrequirenotonlyhighyieldingpotential,whichisdefinedbyyieldcomponenttraits,butalsoanoptimalarchitecturethat,toalargeextent,isdeterminedbyplantheight.Moreover,floweringtime(orheadingdate)isacriticaldeterminantenablingcropstoadapttoseasonalchangesandmakemaximumuseofthetemperatureandsunlightthatareavailableunderspecificecologicalconditions.Yield,plantheightandheadingdatearethreeclassesoftraitsthathavebeenextensivelyinvestigated,andhundredsofQTLshavebeenreportedforthesetraitsintheliterature(seeURLssectioninMethods).Yieldperplantinrice(OryzasativaL.)ismultiplicativelydeterminedbythreecomponenttraits:numberoftillers(panicles)perplant,numberofgrainsperpanicleandgrainweight.Genescontrol-lingthesetraitshavebeenrecentlycloned1–4;eachofthesegenesclearlyhasadistinctbiologicalfunction.Molecularcloningandfunctionalanalysesofseveralgenesassociatedwithplantheightinriceandwheathaveshownthatthesegenesaremostlyrelatedtothesynthesisandregulationofthephytohormonegibberellin5–8.Exten-sivestudiesinArabidopsisthalianahaveestablishedthatfloweringtimeiscontrolledbymultiplepathways9,ofwhichthephotoperiodpathwayactsasamajorone.AkeycomponentfunctioninginthephotoperiodpathwayisthenuclearproteinCONSTANS(CO),whichpromotesfloweringunderlong-dayconditions.Oneofthedown-streamtargetsofCOisaproteinencodedbythefloweringlocusT(FT),which,togetherwithabZIPproteinFD,controlsfloweringtimebyintegratinginputfromvariouspathways10–12.RiceorthologsofbothCO(Hd1)andFT(Hd3a)havebeenidentified13–16,andtheseseemtohaveparallelfunctionsinregulatingfloweringtime,exceptthattheypromotefloweringundershort-dayratherthanlong-dayconditions.Inaddition,twoothergenesregulatingheadingdate,Hd6,encodingthea-subunitofproteinkinaseCK2(ref.17),andEhd1,encodingaB-typeresponseregulator18,havealsobeenidentified.HereweshowthatageneencodingaCCT(CO,CO-LIKEandTIMINGOFCAB1)domainproteinfunctionsasakeyQTLsimulta-neouslycontrollingyield,plantheightandheadingdateinrice.RESULTSAgenomicsegmentwithlargeeffectsonmultipletraitsPreviousstudiesconsistentlydetectedQTLsfornumberofgrainsperpanicle,plantheightandheadingdateintheintervaldefinedbythetwomolecularmarkersR1440andC1023onchromosome7(R1440-C1023;SupplementaryFig.1aonline),usingbothF2:3andrecombinantinbredline(RIL)populationsderivedfromacrossbetweenZhenshan97andMinghui63,theparentsofShanyou63,themostwidelycultivatedricehybridinChina19–24.AtalltheseQTLs,theallelesfromMinghui63simultaneouslyincreasednumberofgrainsperpanicle,plantheightandnumberofdaystoheading.RI50,aRILcontainingthechromosomesegmentR1440-C1023fromMinghui63and74%ofthegeneticbackgroundfromZhenshan97fromapopulationof240RILs,wasbackcrossedtwicetoZhenshan97.Self-pollinationoftheBC2F1plantsheterozygousforthisfragmentresultedinapairofnear-isogeniclines(NILs),designatedNIL(zs7)andNIL(mh7),andaheterozygote,NIL(het),withalmostallthegeneticbackgroundofZhenshan97excepttheintrogressedsegment.Fieldexaminationundernaturallong-dayconditions(daylength414h)showedthatthethreegenotypesdifferedsignificantlyinanarrayoftraits(Fig.1,Table1andSupplementaryTables1and2online),includingheadingdate,plantheightandnumberofspikelets©2008NaturePublishingGroup:10.1038/ng.1431NationalKeyLaboratoryofCropGeneticImprovement,NationalCentreofPlantGeneResearch(Wuhan),HuazhongAgriculturalUniversity,Wuhan430070,China.2Theseauthorscontributedequallytothiswork.CorrespondenceshouldbeaddressedtoQ.Z.([e-mail]).NATUREGENETICSADVANCEONLINEPUBLICATION1ARTICLESperpanicle.HomozygousadditionofR1440-C1023totheZhenshan97geneticbackgrounddelayedheadingby21.2days(33.3%),increasedplantheightby33.3cm(40%)andproduced86(65.8%)morespikeletsonthemainculm(Fig.1andTable1).FurtherexaminationshowedthatNIL(mh7)out-yieldedNIL(zs7)by8.9g(50.9%)perplant,primarilybecauseofanincreaseinnumberofgrainsperpanicle,althoughNIL(mh7)hadfewertillersperplantthanNIL(zs7)(SupplementaryTable1).AnanalysisofaBC3F2populationof192individualsderivedbyself-pollinationoftheBC3F1heterozygotesshowedthateachofthethr