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Descripción
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| In natural environments transition metals are often chelated by organic ligands due to their high binding affinity (1). In the case of endosymbiotic bacteria, bacteroids are surrounded by plant cytoplasm in which metal ions are also complexed by different ligands. Some of these ligands are organic acids, which, at the same time, are the main carbon substrate transferred to bacteroids in legume nodules (2). Provision of metals to endosymbiotic bacteria represents a potential limitation for metalloenzyme synthesis inside legume nodules (3, 4). We have observed a strong effect of the legume host on hydrogenase synthesis when the same Rhizobium leguminosarum bv. viciae strain establishes a symbiotic interaction with pea (Pisum sativum) or lentil (Lens sculenta) plants (5). These data, along with the different phenotypes of mutants altered in nickel transport in these two hosts (6), suggest a role for the chemical form of nickel on metal provision to the bacteroid. Using a novel methodology based on normal phase chromatography with a silica column coupled to UV and MS detection systems we have determined that nickel malate and nickel citrate are the main nickel complexes in pea nodules. In contrast, nodules induced by the same strain in lentil plants contain mostly nickel citrate, although low amounts of nickel malate and nickel tartrate are also present. These results are consistent with the concentrations of each free ligand in the nodule cytosol of these hosts as corrected by the affinity constant of each ligand for nickel. The observed differences in the cytosolic profile of organic acids in pea and lentil hosts suggest a different nature of carbon compounds feeding the bacteroid that might affect microsymbiont's metabolism during symbiotic nitrogen fixation. | |
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Internacional
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Si |
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Nombre congreso
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9th European Nitrogen Fixation Conference |
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Tipo de participación
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960 |
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Lugar del congreso
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Ginebra (Suiza) |
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Revisores
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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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06/09/2010 |
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Fecha fin congreso
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10/09/2010 |
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Desde la página
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261 |
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Hasta la página
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261 |
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Título de las actas
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Book of Abstracts 9th European Nitrogen Fixation Conference |