Mapping the genomic basis of developmental and metabolic responses to nitrogen

Nitrogen (N) is an essential macronutrient that regulates developmental and physiological responses in plants. Although phenotypic and metabolic responses to N in different forms and concentrations have been extensively reported (reviewed in Fredes et al., 2019), these studies have largely focused on the model plant Arabidopsis thaliana accession Columbia (Col-0), and how this information translates to natural variation in N responses is less understood. In this issue of The Plant Cell, Ella Katz and colleagues (Katz et al., 2022) use over a thousand accessions to map various new loci underpinning responses to different N regimens in Arabidopsis. Interestingly, the authors present evidence that combinations of many small effect loci, rather than a few large effect loci, modulate N responses, suggesting that synthetic manipulation of sets of genes is a promising strategy to improve N use efficiency in plants.