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Front. Plant Sci. | doi: 10.3389/fpls.2019.01449

Mitochondrial Iron Transporters (MIT1 and MIT2) are Essential for Iron Homeostasis and Embryogenesis in Arabidopsis thaliana

  • 1National Institutes of Health (NIH), United States
  • 2Biological Sciences, University of South Carolina, United States
  • 3Plant Science Department/ Connolly Lab, Pennsylvania State University, United States

Iron (Fe) is an essential nutrient for virtually all organisms, where it functions in critical electron transfer processes, like those involved in respiration. Photosynthetic organisms have special requirements for Fe due its importance in photosynthesis. While the importance of Fe for mitochondria- and chloroplast-localized processes is clear, our understanding of the molecular mechanisms that underlie the trafficking of Fe to these compartments is not complete. Here, we describe the Arabidopsis mitochondrial iron transporters, MIT1 and MIT2, that belong to the mitochondrial carrier family (MCF) of transport proteins. MIT1 and MIT2 display considerable homology with known mitochondrial Fe transporters of other organisms. Expression of MIT1 or MIT2 rescues the phenotype of the yeast mrs3mrs4 mutant, which is defective in mitochondrial iron transport. Although the Arabidopsis mit1 and mit2 single mutants do not show any significant visible phenotypes, the double mutant mit1mit2 displays embryo lethality. Analysis of a mit1--/mit2+- line revealed that MIT1 and MIT2 are essential for iron acquisition by mitochondria and proper mitochondrial function. In addition, loss of MIT function results in mislocalization of Fe, which in turn causes upregulation of the root high affinity Fe uptake pathway. Thus, MIT1 and MIT2 are required for the maintenance of both mitochondrial and whole plant Fe homeostasis, which, in turn, is important for the proper growth and development of the plant.

Keywords: Mitochondria, Iron, mitochondrial iron transport, Arabidopsis, iron homeostasis, mit, Plant iron homeostasis

Received: 19 Apr 2019; Accepted: 17 Oct 2019.

Copyright: © 2019 Jain, Dashner and Connolly. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Erin L. Connolly, Pennsylvania State University, Plant Science Department/ Connolly Lab, University Park, 16802, Pennsylvania, United States, elc18@psu.edu