In Vivo Metabolic Regulation of Alternative Oxidase under Nutrient Deficiency—Interaction with Arbuscular Mycorrhizal Fungi and Rhizobium Bacteria Ortiz, José Hidalgo Castellanos, Javier López Gómez, Miguel Alternative oxidase Arbuscular mycorrhizal fungi Nitrogen and phosphorus nutrition Rhizobium Plant primary metabolism The interaction of the alternative oxidase (AOX) pathway with nutrient metabolism is important for understanding how respiration modulates ATP synthesis and carbon economy in plants under nutrient deficiency. Although AOX activity reduces the energy yield of respiration, this enzymatic activity is upregulated under stress conditions to maintain the functioning of primary metabolism. The in vivo metabolic regulation of AOX activity by phosphorus (P) and nitrogen (N) and during plant symbioses with Arbuscular mycorrhizal fungi (AMF) and Rhizobium bacteria is still not fully understood. We highlight several findings and open questions concerning the in vivo regulation of AOX activity and its impact on plant metabolism during P deficiency and symbiosis with AMF. We also highlight the need for the identification of which metabolic regulatory factors of AOX activity are related to N availability and nitrogen-fixing legume-rhizobia symbiosis in order to improve our understanding of N assimilation and biological nitrogen fixation. 2020-09-11T10:44:03Z 2020-09-11T10:44:03Z 2020-06-12 journal article Ortíz, J., Sanhueza, C., Romero-Munar, A., Castro, J. H. C. C., Bascuñán-Godoy, L., Coba de la Peña, T., ... & Del-Saz, N. F. (2020). In Vivo Metabolic Regulation of Alternative Oxidase under Nutrient Deficiency—Interaction with Arbuscular Mycorrhizal Fungi and Rhizobium Bacteria. International Journal of Molecular Sciences, 21(12), 4201. [doi:10.3390/ijms21124201] http://hdl.handle.net/10481/63390 10.3390/ijms21124201 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España MDPI