%ASenovilla, Marta [Centro de Biotecnología y Genómica de Plantas (UPM‐INIA) Universidad Politécnica de Madrid Campus de Montegancedo, Crta, M‐40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%ASenovilla, Marta [Centro de Biotecnología y Genómica de Plantas (UPM-INIA); Universidad Politécnica de Madrid; Campus de Montegancedo, Crta, M-40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%ACastro‐Rodríguez, Rosario [Centro de Biotecnología y Genómica de Plantas (UPM‐INIA) Universidad Politécnica de Madrid Campus de Montegancedo, Crta, M‐40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%ACastro-Rodríguez, Rosario [Centro de Biotecnología y Genómica de Plantas (UPM-INIA); Universidad Politécnica de Madrid; Campus de Montegancedo, Crta, M-40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%AAbreu, Isidro [Centro de Biotecnología y Genómica de Plantas (UPM‐INIA) Universidad Politécnica de Madrid Campus de Montegancedo, Crta, M‐40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%AAbreu, Isidro [Centro de Biotecnología y Genómica de Plantas (UPM-INIA); Universidad Politécnica de Madrid; Campus de Montegancedo, Crta, M-40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%AEscudero, Viviana [Centro de Biotecnología y Genómica de Plantas (UPM‐INIA) Universidad Politécnica de Madrid Campus de Montegancedo, Crta, M‐40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%AEscudero, Viviana [Centro de Biotecnología y Genómica de Plantas (UPM-INIA); Universidad Politécnica de Madrid; Campus de Montegancedo, Crta, M-40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%AKryvoruchko, Igor [Plant Biology Division The Samuel Roberts Noble Foundation Ardmore OK 73401 USA]%AKryvoruchko, Igor [Plant Biology Division; The Samuel Roberts Noble Foundation; Ardmore OK 73401 USA]%AUdvardi, Michael [Plant Biology Division The Samuel Roberts Noble Foundation Ardmore OK 73401 USA]%AUdvardi, Michael [Plant Biology Division; The Samuel Roberts Noble Foundation; Ardmore OK 73401 USA]%AImperial, Juan [Centro de Biotecnología y Genómica de Plantas (UPM-INIA); Universidad Politécnica de Madrid; Campus de Montegancedo, Crta, M-40 km 38 Pozuelo de Alarcón Madrid 28223 Spain; Instituto de Ciencias Agrarias; Consejo Superior de Investigaciones Científicas; Serrano, 115 bis Madrid 28006 Spain]%AImperial, Juan [Centro de Biotecnología y Genómica de Plantas (UPM‐INIA) Universidad Politécnica de Madrid Campus de Montegancedo, Crta, M‐40 km 38 Pozuelo de Alarcón Madrid 28223 Spain, Instituto de Ciencias Agrarias Consejo Superior de Investigaciones Científicas Serrano, 115 bis Madrid 28006 Spain]%AGonzález‐Guerrero, Manuel [Centro de Biotecnología y Genómica de Plantas (UPM‐INIA) Universidad Politécnica de Madrid Campus de Montegancedo, Crta, M‐40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%AGonzález-Guerrero, Manuel [Centro de Biotecnología y Genómica de Plantas (UPM-INIA); Universidad Politécnica de Madrid; Campus de Montegancedo, Crta, M-40 km 38 Pozuelo de Alarcón Madrid 28223 Spain]%BJournal Name: New Phytologist; Journal Volume: 218; Journal Issue: 2; Related Information: CHORUS Timestamp: 2023-09-16 13:12:25 %D2018%IWiley-Blackwell %JJournal Name: New Phytologist; Journal Volume: 218; Journal Issue: 2; Related Information: CHORUS Timestamp: 2023-09-16 13:12:25 %K %MOSTI ID: 10049869 %PMedium: X %TMedicago truncatula copper transporter 1 (Mt COPT 1) delivers copper for symbiotic nitrogen fixation %XSummary

Copper is an essential nutrient for symbiotic nitrogen fixation. This element is delivered by the host plant to the nodule, where membrane copper (Cu) transporter would introduce it into the cell to synthesize cupro‐proteins.

COPTfamily members in the model legumeMedicago truncatulawere identified and their expression determined. Yeast complementation assays, confocal microscopy and phenotypical characterization of aTnt1insertional mutant line were carried out in the nodule‐specificM. truncatulaCOPTfamily member.

Medicago truncatulagenome encodes eightCOPTtransporters.MtCOPT1(Medtr4g019870) is the only nodule‐specificCOPTgene. It is located in the plasma membrane of the differentiation, interzone and early fixation zones. Loss of MtCOPT1 function results in a Cu‐mitigated reduction of biomass production when the plant obtains its nitrogen exclusively from symbiotic nitrogen fixation. Mutation ofMtCOPT1results in diminished nitrogenase activity in nodules, likely an indirect effect from the loss of a Cu‐dependent function, such as cytochrome oxidase activity incopt1‐1bacteroids.

These data are consistent with a model in which MtCOPT1 transports Cu from the apoplast into nodule cells to provide Cu for essential metabolic processes associated with symbiotic nitrogen fixation.

%0Journal Article