Rivero Marcos, MikelLasa Larrea, BertaNeves, ToméZamarreño, Ángel M.García Mina, José M.García Olaverri, CarmenAparicio Tejo, Pedro MaríaCruz, CristinaAriz Arnedo, Idoia2024-11-192024-11-192024-03-11Rivero-Marcos, M., Lasa, B., Neves, T., Zamarreño, A. M., García-Mina, J. M., García-Olaverri, C., Aparicio-Tejo, P. M., Cruz, C., Ariz, I. (2024). Plant ammonium sensitivity is associated with external pH adaptation, repertoire of nitrogen transporters, and nitrogen requirement. Journal of Experimental Botany, 75(11), 3557-3578. https://doi.org/10.1093/jxb/erae106.0022-095710.1093/jxb/erae106https://academica-e.unavarra.es/handle/2454/52535Modern crops exhibit diverse sensitivities to ammonium as the primary nitrogen source, influenced by environmental factors such as external pH and nutrient availability. Despite its significance, there is currently no systematic classification of plant species based on their ammonium sensitivity. We conducted a meta-analysis of 50 plant species and present a new classification method based on the comparison of fresh biomass obtained under ammonium and nitrate nutrition. The classification uses the natural logarithm of the biomass ratio as the size effect indicator of ammonium sensitivity. This numerical parameter is associated with critical factors for nitrogen demand and form preference, such as Ellenberg indicators and the repertoire of nitrogen transporters for ammonium and nitrate uptake. Finally, a comparative analysis of the developmental and metabolic responses, including hormonal balance, is conducted in two species with divergent ammonium sensitivity values in the classification. Results indicate that nitrate has a key role in counteracting ammonium toxicity in species with a higher abundance of genes encoding NRT2-type proteins and fewer of those encoding the AMT2-type proteins. Additionally, the study demonstrates the reliability of the phytohormone balance and methylglyoxal content as indicators for anticipating ammonium toxicity. This study emphasizes the importance of ecophysiological requirements and the repertoire of nitrogen transporters in understanding plant sensitivity to ammonium, and enhances our knowledge of plant nitrogen nutrition.application/pdfapplication/zipeng© The Author(s) 2024. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Ammonium sensitivityAmmonium transporters (AMTs)Ellenberg indicatorHigh-affinity nitrate transporter (NRT2)MethylglyoxalNitrogen uptakepH adaptationPhytohormonal balanceinfo:eu-repo/semantics/article2024-11-19info:eu-repo/semantics/openAccess