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Nodule development on the tropical legume Sesbania virgata under flooded and non-flooded conditions

Authors

  • C. A. Bomfeti,

    1.  Instituto de Ciência e Tecnologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Teófilo Otani Minas Gerais, Brazil
    2.  Departamento de Ciência do Solo, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil
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  • P. A. A. Ferreira,

    1.  Departamento de Ciência do Solo, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil
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  • T. S. Carvalho,

    1.  Departamento de Ciência do Solo, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil
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  • R. De Rycke,

    1.  Department of Plant Systems Biology, VIB, Gent, Belgium
    2.  Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • F. M. S. Moreira,

    1.  Departamento de Ciência do Solo, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil
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  • S. Goormachtig,

    1.  Department of Plant Systems Biology, VIB, Gent, Belgium
    2.  Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • M. Holsters

    1.  Department of Plant Systems Biology, VIB, Gent, Belgium
    2.  Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Editor
    P. Franken

S. Goormachtig, Departments of Plant Systems Biology and Plant Biotechnology and Bioinformatics, VIB-Ghent University, Technologiepark 927, 9052 Gent, Belgium.
E-mail: sofie.goormachtig@ugent.be

Abstract

The interaction between the Brazilian pioneer legume Sesbania virgata and its microsymbiont Azorhizobium doebereinerae leads to the formation of nitrogen-fixing nodules on roots that grow either in well-aerated soils or in wetlands. We studied the initiation and development of nodules under these alternative conditions. To this end, light and fluorescence microscopy were used to follow the bacterial colonisation and invasion into the host and, by means of transmission electron microscopy, we could observe the intracellular entry. Under hydroponic conditions, intercellular invasion took place at lateral root bases and mature nodules were round and determinate. However, on roots grown in vermiculite that allows aerated growth, bacteria also entered via root hair invasion and nodules were both of the determinate and indeterminate type. Such versatility in entry and developmental plasticity, as previously described in Sesbania rostrata, enables efficient nodulation in both dry and wet environments and are an important adaptive feature of this group of semi-tropical plants that grow in temporarily flooded habitats.

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