Identification of regulatory genes from chalky/floury endosperm mutants is an important approach to understand the mechanism of starch biosynthesis to accelerate rice grain quality improvement.A mutant GM645,identified from 60Co y-irradiation of an indica rice Guanglu'ai 4(GLA4),exhibited white-core endosperm and altered starch physicochemical properties.However,the causal gene responsible for the white-core endosperm in GM645 has not been identified.Here,we developed a recombined inbred line(RIL,F7)population derived from a cross between GM645 and a japonica rice Tainong 67(TN67)with translucent endosperm.Bulked-segregant analysis combined with next generation sequencing revealed five single nucleotide polymorphisms(SNPs)in four candidate genes that were highly associated with the white-core endosperm.Among them,one base pair deletion in Os04g0645100 resulted in a frame shift mutation after the 983th amino acid(aa),and a premature stop codon occurred after the other 11 aa.Moreover,functional annotation revealed that Os04g0645100 was previously characterized as the FLOURY ENDOSPERM2(FLO2)gene.Full-length coding sequence from Os04g0645100 driven by the maize ubiquitin promoter was transformed into GM645,and seeds from these transgenic plants expressing Os04g0645100 were largely rescued to translucent,indicating that Os04g0645100 was responsible for the white-core endosperm in GM645.

BAO Jinsong;ZHANG Yu;ZHAO Jiajia;CHEN Yaling;Wu Weixun;CAO Liyong;Xu Feifei

Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Rural Affairs and Zhejiang Province/Institute of Nuclear Agricultural Sciences,College of Agriculture and Biotechnology Zhejiang University,Hangzhou 310058,China;Hainan Institute of Zhejiang University,Yazhou District,Sanya 572025,China;Laboratory of Plant Genetic Improvement and Biotechnology,Jiangxi Normal University,Nanchang 330000,China;State Key Laboratory of Rice Biology/Chinese National Center for Rice Improvement,China National Rice Research Institute,Hangzhou 310006,China

水稻科学（英文版）

[1]BAO Jinsong;ZHANG Yu;ZHAO Jiajia;CHEN Yaling;Wu Weixun;CAO Liyong;Xu Feifei-.Identification of New Allele of FLOURY ENDOSPERM2 in White-Core Endosperm Mutant of Rice)[J].水稻科学（英文版）,2022(05):407-411,中插17-中插18

FLOURY,ENDOSPERM2,Endosperm,floury,GM645,Guanglu,GLA4,Tainong,TN67,Os04g0645100,983th,FLO2

Identification,New,Allele,White,Core,Mutant,Rice,regulatory,genes,from,chalky,endosperm,mutants,important,approach,understand,mechanism,starch,biosynthesis,accelerate,rice,grain,quality,improvement,identified,60Co,irradiation,exhibited,white,core,altered,physicochemical,properties,However,causal,responsible,has,been,Here,developed,recombined,inbred,line,RIL,F7,population,derived,cross,between,japonica,translucent,Bulked,segregant,analysis,next,generation,sequencing,revealed,five,single,nucleotide,polymorphisms,SNPs,four,candidate,that,were,highly,associated,Among,them,one,base,pair,deletion,resulted,frame,shift,mutation,after,amino,acid,aa,premature,stop,codon,occurred,other,Moreover,functional,annotation,was,previously,characterized,Full,length,coding,sequence,driven,by,maize,ubiquitin,promoter,transformed,into,seeds,these,transgenic,plants,expressing,largely,rescued,indicating

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