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Descripción
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| Metals are essential micronutrients for symbiotic nitrogen fixation as cofactors of key enzymes involved in this process, such as nitrogenase, leghemoglobin, and cytochrome oxidases (1). Previous results in Medicago truncatula showed that these metals are provided to the nitrogen-fixing bacteroids by the host legume. They are loaded in the roots vascular cylinder, where they are redirected to the nodule. Once there, metals are released to the apoplast of infection zone of the nodule (2) and they are introduced into the infected cells. Therefore, there must be several metal transporters mediating the transport from the vascular bundle. Members of yellow stripe-like (YSL) family of metal transporters are importants players in the long-distance transport of metals between source and sink organs in plants. For this reason, many of them are often associated to the vasculature (3). We hipotetize that one YSL family member could be responsible for delivering metals from the vasculature to the nodule apoplast. Transcription profiles of the 9 YSL family members in M. truncatula, showed that one ot them, MtYSL8, has the highest expression in nodule. This transporter could be a good candidate to transport metal through the vessels in nodules. Supporting this, we have found that MtYSL8 was localized around the nodule vascular bundles, and in the root vascular cylinder. MtYSL8 inmunolocalization experiments showed that it is localized in the plasma membrane of non-infected cells surrounding vessels of the nodule. In roots, it is localized in the stele, in close proximity to the xylem. Under symbiotic conditions, ysl8-1 mutant plants show growth defects and a 50% reduction of the nitrogenase activity respect to control plants. Under non-symbiotic conditions (plants watered with a nutritive solution containing ammonium nitrate), ysl8-1 mutants exhibited normal, wild type-like growth. All these results point to a role of MtYSL8 in metal delivery for nitrogen fixation in M. truncatula nodules. | |
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Internacional
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Si |
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Nombre congreso
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International Nitrogen Fixation Conference |
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Tipo de participación
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970 |
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Lugar del congreso
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Revisores
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Si |
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ISBN o ISSN
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0000000000 |
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DOI
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Fecha inicio congreso
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03/09/2017 |
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Fecha fin congreso
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07/09/2017 |
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Desde la página
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155 |
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Hasta la página
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155 |
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Título de las actas
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International Nitrogen Fixation Conference |