摘要
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
generous support of Western Crop Genetics Alliance,Murdoch University,Western Australia
awarded a Murdoch International Postgraduate Scholarship。
