简介：Themajorstoragesubstanceinriceendospermisstarch,whichaccountsfor80%ofdrymatterweight.Inthisstudy,ricemutantflo7,selectedfromtheprogenyofNipponbare’stissueculture,displayedflouryandopaqueendosperm.Comparedwithitscorrespondingwildtype(WT)Nipponbare,themutantflo7producedlonger,narrower,thinnerandlightergrains.Thelevelsofglucose,fructoseandsucroseinthemutantflo7endospermwerehigherthanthoseintheWTendosperm,whereastheproteincontentwasnotaffected.Withrespecttobothamylosecontentandgelconsistency,themutantflo7waslowerthanWT,butitsalkalivaluewashigher.Scanningelectronmicroscopicexaminationsshowedthattheendospermofthemutantflo7containedirregular,looselypackedandcompoundstarchgranules.Geneticanalysisindicatedthatthemutantphenotypewasdeterminedbyasinglerecessivenucleargene.Theflo7locuswasmappedtoaregiononthelongarmofchromosome12,withina95.1kbintervaldefinedbythemarkersC2-11andC5-15.Thereare13openreadingframesinthemappinginterval.Transcriptionprofilingofthedevelopinggrainsshowedthatanumberofgenesinvolvedinstarchsynthesiswereaffecteddifferentlyinthemutantflo7.