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Descripción
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| Iron is an essential nutrient for Symbiotic Nitrogen Fixation (SNF) being present as cofactor in the active center of key enzymes involved in this process, such as nitrogenase, leghemoglobin, and cytochrome oxidases (1). In legumes, iron is provided to the nitrogen-fixing bacteroids by the host legume through the vasculature, being released to the apoplast of infection zone of the nodule (2). Once there, iron has to be introduced across the plasma membrane into rhizobia infected cells by an iron transporter. We have identified MtNramp1 as responsible for iron transport from the nodule apoplast into rhizobia infected cells. MtNramp1 has the highest expression in the nodule among the seven Nramp genes present in Medicago truncatula genome. Inmunolocalization studies show that MtNramp1 is localized in the plasma membrane of infection zone of the nodule. Furthermore, yeast complementation assays point to a role of MtNramp1 in iron transport towards the cytosol. Under symbiotic conditions (plants inoculated with nitrogen-fixing rhizobia), nramp1-1 mutant plants show growth defects and inactive nodules, concomitant with a 60% reduction of the nitrogenase activity respect to control plants. This phenotype was restored by complementation with a wild-type MtNramp1 copy or by watering with an iron-fortified solution. All these results point to a role of MtNramp1 in iron supply to nodule infected cells connected to SNF, and represent an important step toward the understanding of iron incorporation and homeostasis in nitrogen-fixing plants. | |
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Internacional
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Si |
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Nombre congreso
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Workshop New Frontiers in Plant Biology |
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Tipo de participación
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970 |
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Lugar del congreso
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Centro de Biotecnología y Genómica de Plantas |
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Revisores
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Si |
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ISBN o ISSN
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0000-0000 |
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DOI
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Fecha inicio congreso
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15/06/2016 |
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Fecha fin congreso
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17/06/2016 |
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Desde la página
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6 |
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Hasta la página
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6 |
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Título de las actas
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MtNramp1 provides iron to rhizobia-infected Medicago truncatula nodule cells. |