Zinc is required for legume nodule development

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 in differentiated root organs (nodules) 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 that zinc delivery to nodule cells is required for nodule development. This is mediated by endoplasmic reticulum transporter MtMTP2. When mutated, nodules do not develop properly and reach early senescence. This work hints at the existence of a group of zinc proteins that mediate nodule organogenesis and/or maintenance.

Original Paper:

León-Mediavilla, J; Senovilla, M; Montiel, J; Gil-Díez, P; Saez, Á; Kryvoruchko, IS; Reguera, M; Udvardi, MK; Imperial, J; González-Guerrero, M. 2018. "MtMTP2-facilitated zinc transport into intracellular compartments is essential for nodule development in Medicago truncatula". Frontiers in Plant Science. DOI: 10.3389/fpls.2018.00990".