Understanding the physiological and molecular basis for differences in nitrogen use efficiency in the parents of a winter wheat MAGIC population

Authors: LIGEZA, ALEKSANDER - Processors And Growers Research Organization; Milner, Matthew

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2024
Publication Date: 11/28/2024
Citation: Ligeza, A., Milner, M.J. 2024. Understanding the physiological and molecular basis for differences in nitrogen use efficiency in the parents of a winter wheat MAGIC population. Plants. 13(23). Article 3331. https://doi.org/10.3390/plants13233331.
DOI: https://doi.org/10.3390/plants13233331

Interpretive Summary: Improving fertilizer use by crops is difficult as many genes in a plant can have effects on how the fertilizer provided to the plant enhances food production. A better understanding of how a diverse set of wheat varieties behave under a range of nitrogen impacts of food production and can limit wasted resources and the environmental impact of food production. Nitrogen is the most applied fertilizer and poorly utilized by plants. It is also the main driver of greenhouse gas emissions involved in food production. By improving our understanding of how plants take up and use nitrogen at varying levels we can improve the cost and lower the environmental impacts of food production. We found from testing a diverse set of wheat germplasm with many different end uses, that their response varies to the supply of additional nitrogen. While all the varieties of wheat tested responded to the additional nitrogen supplied, the varieties did not react the same way to the added nitrogen in terms of growth, grain produced and grain protein content. We show that the amount and rate of uptake of nitrogen from the soil is not the basis for the differences observed in growth to varying nitrogen supply. A more in-depth comparison of two bread making quality lines was undertaken and found that genes regulated by nitrogen are not the reason for under differences in response to nitrogen but differences in how the nitrogen is perceived by the plant may be involved. This information will allow us to breed better adapted wheat for many end uses with lower costs of production and lower environmental impact.

Technical Abstract: The need to improve both the cost of food production as well as the environmental impact of food production is key to being able to sustainably feed the projected growth of the human population. To attempt to understand how to improve yields under lower nitrogen (N) inputs, a diverse set of UK winter wheats encompassing ~80% of the genetic diversity in the UK were grown under a range of N levels and their performance measured under various levels of N. Growth by the eight parents of this MAGIC population showed significant differences in biomass per plant, ear number, yield and protein content of the grain when grown differing levels of N. Furthermore, no consistent response to N was seen for the lines tested for all the traits measured. Underlying differences by the varieties tested in response to N was not due to N uptake or N translocation. As short term 15N uptake and translocation showed no significant differences in the lines tested. RNASeq was then performed on two different bread making varieties grown under low N conditions to identify putative genes controlling the underlying differences seen in biomass production when grown on low N. This led to the identification of the genes involved in C/N signaling and metabolism which may explain the differences in growth and biomass produced between Xi19 and Hereward.