| Summary: | CassavagenetictransformationcapacityisstillmostlyrestrictedtoadvancedlaboratoriesintheUSA,EuropeandChina;anditsimplementationandmaintenanceinAfricanlaboratorieshasremainedscarce.TheimpactoftransgenictechnologiesforgeneticimprovementofcassavawilldependlargelyonthetransferofsuchcapabilitiestoresearchersinAfrica,wherecassavahasanimportantsocioeconomicniche.Amajorconstrainttothedevelopmentofgenetictransformationtechnologiesforcassavaimprovementhasbeenthelackofanefficientandrobusttransformationandregenerationsystem.Despitethesuccessachievedingeneticmodificationoffewcassavacultivars,includingthemodelcultivar60444,transgeniccassavaproductionremainsdifficultforfarmer-preferredcultivars.Inthisstudy,aprotocolforcultivar60444developedatETHZurichwassuccessfullyimplementedandoptimizedtoestablishtransformationoffarmer-preferredcassavacultivarspopularineastAfrica.Theconditionsforproductionandproliferationoffriableembryogeniccalli(FEC)andAgrobacterium-mediatedtransformationwereoptimizedforthreeeastAfricanfarmer-preferredcultivars(Ebwanatereka,KibandamenoandSerere).Ourresultsdemonstratedtransformationefficienciesofabout14–22independenttransgeniclinesper100mgofFECforfarmer-preferredcultivarsincomparisonto28linesper100mgofthemodelcultivar60444.Thepresence,integrationandexpressionofthetransgeneswereconfirmedbyPCR,SouthernblotanalysisandhistochemicalGUSassay.ThisstudyreportstheestablishmentofacassavatransformationplatformatInternationalInstituteofTropicalAgriculture(IITA)hostedbyBioscienceseasternandcentralAfrica(BecA)hubinKenyaandprovidesthebasisfortransferringimportanttraitssuchasvirusresistanceandprolongedshelf-lifetofarmer-preferredcultivarsineastAfrica.Weanticipatethatsuchplatformwillalsobeinstrumentaltotransfertechnologiestonationalagriculturalresearchsystems(NARS)insub-SaharanAfrica.
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