* Corresponding author. E-mail address: liuluxiang@caas.cn.

The Green Revolution, based on dwarf breeding, has skyrocketed wheat grain yields mainly through the regulation of phytohormone gibberellin (GA) metabolism and signal transduction. Currently, alleles of available dwarf genes are very poor in breeding, and nitrogen use efficiency has been negatively affected.

Novel allelic variations are therefore essential for expanding dwarf gene resources and cultivating green and efficient wheat dwarf varieties. In this project, we will take the GA-sensitive Rht8 cloned by the project team and the GA-insensitive Rht-1 (Green Revolution gene) as research objects.

By using the wheat mutant library and surrogate prime editors developed previously, we will create innovative dwarf mutants and obtain target mutations in the promoter region, UTR, and important functional domains.

Moreover, we will further analyze the effects of various allelic variations on plant height, nitrogen use efficiency, and yield under low nitrogen and normal nitrogen conditions and screen for variant types that are superior to the Green Revolution dwarfing alleles.

Finally, we will analyze the mechanism by which different allelic variations affect gene function, examine the expression changes of GRF4/NGR5 (GA signaling and the nitrogen utilization key transcription factors) and nitrate transporter TaNRT2 in mutants, and identify molecular modules that can enhance yields and nitrogen use efficiency synergistically.

The findings will contribute to the precise utilization of dwarf genes for breeding, thus providing a creative strategy to design high-yield and high-efficiency wheat varieties.