Thesis abstract:

Nitrogen use in the cereals industry is applied to increase production, however approximately 50% of this applied N is not taken up by plants. The production and accumulation of N fertilisers is quite harmful to the environment. Plant inorganic N transporters such as nitrate transporters (NPF6) are involved in the uptake of nitrate in plants. By improving transporters affinity to N and understanding its role in N transport we can improve plant NUE. Structural alteration of a his residue in NPF6 genes in Xenopus laevis oocytes have changed the functionality of this transporter from a chloride selective low affinity transporter to one that increases nitrate selectivity (Wen et al. 2017). Differential expression of select NPF genes in Maize roots influences root development and nitrogen acquisition strategies. A majority NPF6 orthologs in maize and barley retain a tyrosine instead of a histidine residue within this structure. Thus the aims of this project are to modify key NPF6 genes, via a CRISPR-cas9 approach in maize and barley to change their nitrate selectivity. Evaluation of these modifications on root growth, yield and NUE will be carried out.