Iron Transport across Symbiotic Membranes of Nitrogen-Fixing Legumes

David A. Day 1,* and Penelope M. C. Smith 2

1 College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
2 School of Life Sciences, La Trobe University, Melbourne, VIC 3083, Australia; P.Smith3@latrobe.edu.au
* Correspondence: David.Day@flinders.edu.au

Abstract
Iron is an essential nutrient for the legume-rhizobia symbiosis and nitrogen-fixing bacteroids within root nodules of legumes have a very high demand for the metal. Within the infected cells of nodules, the bacteroids are surrounded by a plant membrane to form an organelle-like structure called the symbiosome. In this review, we focus on how iron is transported across the symbiosome membrane and accessed by the bacteroids.

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Keywords
 legumes; nitrogen fixation; symbiosomes; iron