Wheat 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
nitrogen use efficiency (NUE) of modern wheat varieties are aggravating
environmental pollution and ecological deterioration. In rice,
an/are1/mutant possesses the increased NUE under nitrogen-limiting
conditions, delayed senescence and consequently increased grain yield.
However, the function of/ARE1/ortholog in wheat remains unknown. Here,
we isolated and characterized three/TaARE1/homeologs in an elite Chinese
winter wheat/cv/ZhengMai 7698. We then generated a series of
transgene-free mutant lines either with partial or triple
null/taare1/alleles through CRISPR/Cas9-mediated targeted mutagenesis
of/TaARE1/. All transgene-free mutant lines showed enhanced tolerance to
nitrogen starvation, and delayed senescence and increased grain yield in
a field experiment.

Increasing yield potential through manipulating of an ARE1 ortholog
related to nitrogen use efficiency in wheat by CRISPR/Cas9 - Zhang - -
Journal of Integrative Plant Biology - Wiley Online Library
[onlinelibrary.wiley.com]