In Vivo Metabolic Regulation of Alternative Oxidase under Nutrient Deficiency—Interaction with Arbuscular Mycorrhizal Fungi and <em>Rhizobium </em>Bacteria

• Main Authors: José Ortíz, Carolina Sanhueza, Antònia Romero-Munar, Javier Hidalgo-Castellanos Catalina Castro, Luisa Bascuñán-Godoy, Teodoro Coba de la Peña, Miguel López-Gómez, Igor Florez-Sarasa, Néstor Fernández Del-Saz
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: International Journal of Molecular Sciences
• Subjects: alternative oxidase; arbuscular mycorrhizal fungi; nitrogen and phosphorus nutrition; rhizobium; plant primary metabolism
• Online Access: https://www.mdpi.com/1422-0067/21/12/4201

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 <i>Rhizobium</i> 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.