Nitrogen is a major determinant of grain yield and quality.As excessive use of nitrogen fertilizer leads to environmental pollution and high production costs,improving nitrogen use efficiency(NUE)is fundamental for a ...Nitrogen is a major determinant of grain yield and quality.As excessive use of nitrogen fertilizer leads to environmental pollution and high production costs,improving nitrogen use efficiency(NUE)is fundamental for a sustainable agriculture.Here,we dissected the role of the barley abnormal cytokinin response1 repressor 1(Hv ARE1)gene,a candidate for involvement in NUE previously identified in a genome-wide association study,through natural variation analysis and clustered regularly interspacedshort palindromic repeats(CRISPR)/CRISPRassociated protein 9(Cas9)-mediated gene editing.Hv ARE1 was predominantly expressed in leaves and shoots,with very low expression in roots under low nitrogen conditions.Agrobacterium-mediated genetic transformation of immature embryos(cv.Golden Promise)with single guide RNAs targeting Hv ARE1 generated 22 T0 plants,from which four T1 lines harbored missense and/or frameshift mutations based on genotyping.Mutant are1 lines exhibited an increase in plant height,tiller number,grain protein content,and yield.Moreover,we observed a 1.5-to2.8-fold increase in total chlorophyll content in the flag leaf at the grain filling stage.Delayed senescence by 10–14 d was also observed in mutant lines.Barley are1 mutants had high nitrogen content in shoots under low nitrogen conditions.These findings demonstrate the potential of ARE1 in NUE improvement in barley.展开更多
Wheat(Triticum aestivum L.)is a staple food crop consumed by more than 30%of world population.Nitrogen(N)fertilizer has been applied broadly in agriculture practice to improve wheat yield to meet the growing demands f...Wheat(Triticum aestivum L.)is a staple food crop consumed by more than 30%of world population.Nitrogen(N)fertilizer has been applied broadly in agriculture practice to improve wheat yield to meet the growing demands for food production.However,undue N fertilizer application and the low N use efficiency(NUE)of modern wheat varieties are aggravating environmental pollution and ecological deterioration.Under nitrogen-limiting conditions,the rice(Oryza sativa)abnormal cytokinin response1 repressor1(are1)mutant exhibits increased NUE,delayed senescence and consequently,increased grain yield.However,the function of ARE1 ortholog in wheat remains unknown.Here,we isolated and characterized three TaARE1 homoeologs from the elite Chinese winter wheat cultivar ZhengMai 7698.We then used CRISPR/Cas9-mediated targeted mutagenesis to generate a series of transgene-free mutant lines either with partial or triple-null taare1 alleles.All transgene-free mutant lines showed enhanced tolerance to N starvation,and showed delayed senescence and increased grain yield in field conditions.In particular,the AABBdd and aabbDD mutant lines exhibited delayed senescence and significantly increased grain yield without growth defects compared to the wild-type control.Together,our results underscore the potential to manipulate ARE1 orthologs through gene editing for breeding of high-yield wheat as well as other cereal crops with improved NUE.展开更多
基金generous support of Western Crop Genetics Alliance,Murdoch University,Western Australiaawarded a Murdoch International Postgraduate Scholarship。
文摘Nitrogen is a major determinant of grain yield and quality.As excessive use of nitrogen fertilizer leads to environmental pollution and high production costs,improving nitrogen use efficiency(NUE)is fundamental for a sustainable agriculture.Here,we dissected the role of the barley abnormal cytokinin response1 repressor 1(Hv ARE1)gene,a candidate for involvement in NUE previously identified in a genome-wide association study,through natural variation analysis and clustered regularly interspacedshort palindromic repeats(CRISPR)/CRISPRassociated protein 9(Cas9)-mediated gene editing.Hv ARE1 was predominantly expressed in leaves and shoots,with very low expression in roots under low nitrogen conditions.Agrobacterium-mediated genetic transformation of immature embryos(cv.Golden Promise)with single guide RNAs targeting Hv ARE1 generated 22 T0 plants,from which four T1 lines harbored missense and/or frameshift mutations based on genotyping.Mutant are1 lines exhibited an increase in plant height,tiller number,grain protein content,and yield.Moreover,we observed a 1.5-to2.8-fold increase in total chlorophyll content in the flag leaf at the grain filling stage.Delayed senescence by 10–14 d was also observed in mutant lines.Barley are1 mutants had high nitrogen content in shoots under low nitrogen conditions.These findings demonstrate the potential of ARE1 in NUE improvement in barley.
基金funded by National Key Research and Development Program of China(2020YFE0202300)the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202109)+1 种基金Fundamental Research Funds for Central Non-Profit of Institute of Crop Sciences,Chinese Academy of Agricultural Sciences(S2021ZD03)National Engineering Laboratory of Crop Molecular Breeding。
文摘Wheat(Triticum aestivum L.)is a staple food crop consumed by more than 30%of world population.Nitrogen(N)fertilizer has been applied broadly in agriculture practice to improve wheat yield to meet the growing demands for food production.However,undue N fertilizer application and the low N use efficiency(NUE)of modern wheat varieties are aggravating environmental pollution and ecological deterioration.Under nitrogen-limiting conditions,the rice(Oryza sativa)abnormal cytokinin response1 repressor1(are1)mutant exhibits increased NUE,delayed senescence and consequently,increased grain yield.However,the function of ARE1 ortholog in wheat remains unknown.Here,we isolated and characterized three TaARE1 homoeologs from the elite Chinese winter wheat cultivar ZhengMai 7698.We then used CRISPR/Cas9-mediated targeted mutagenesis to generate a series of transgene-free mutant lines either with partial or triple-null taare1 alleles.All transgene-free mutant lines showed enhanced tolerance to N starvation,and showed delayed senescence and increased grain yield in field conditions.In particular,the AABBdd and aabbDD mutant lines exhibited delayed senescence and significantly increased grain yield without growth defects compared to the wild-type control.Together,our results underscore the potential to manipulate ARE1 orthologs through gene editing for breeding of high-yield wheat as well as other cereal crops with improved NUE.
