Jiahui Zhang, Huating Zhang, Shaoya Li, Jingying Li, Lei Yan, Lanqin Xia

Journal of Integrative Plant Biology; First published: 16 July 2021, https://doi.org/10.1111/jipb.13151

Abstract

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. In particular, AABBdd and aabbDD mutant lines exhibited delayed senescence and significantly increased grain yield without growth defects in comparison with 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.

See: https://onlinelibrary.wiley.com/doi/abs/10.1111/jipb.13151