MtCOPT1 mediates copper uptake by nodule cells in legume Medicago truncatula

The massive use of nitrogen fertilizers in agriculture is responsible of feeding half of the world population. However, they are an important source of greenhouse gasses, one of the main expenses for farmers (unreacheable in many developing countries), and contribute to water eutrophyzation. Symbiotic nitrogen fixation (SNF) carried out by the rhizobia-legume interaction is one of the main alternatives to the overuse of these fertilizers, in a return to more sustainable practices of crop rotation with legumes. This process requires of relatively large amount of transition metals (iron, copper, zinc,…) that work as cofactors of many of the main enzymes participating in SNF. Given the prevalent low bioavailability of these metals in many of the main agricultural areas of the world, the real impact of crop rotation with legumes in soil nitrogen fertilization will depend in ensuring a continous and suficient delivery of essential transition metals. To improve this, we need to identify and manipulate the transporters mediating the delivery of these nutrients.

The CBGP group “Metal homeostasis in plant-microbe interactions”, in collaboration with researchers from CSIC, and the Noble Research Institute (USA), has recently published the characterization of the transporter responsible for copper delivery to nitrogen-fixing cells in the nodules of model legume Medicago truncatula. This is a plasma membrane transporter that introduces copper into the cell cytosol. Reduction of the expression levels of this transporter results in the reduction of nitrogen fixation capabilities in nodules. Among other factors, this is due to the reduction of Cu-dependent cytochrome oxidase activity.

Original Paper:

Senovilla, M; Castro-Rodríguez, R; Abreu, I; Escudero, V ; Kryvoruchko, I; Udvardi, MK; Imperial, J; González-Guerrero, M. 2018. "Medicago truncatula copper transporter 1 (MtCOPT1) delivers copper for symbiotic nitrogen fixation". New Phytologist. DOI: 10.1111/nph.14992".