Induction of cdc2a and cyc1At expression in Arabidopsis thaliana during early phases of nematode-induced feeding cell formation

Authors

  • Andreas Niebel,

    1. Laboratorium voor Genetica, Department of Genetics, Flanders Interuniversity Institute for Biotechnology, Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium, and
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    • These authors have contributed equally to this work.

    • Present address: Laboratoire de Biologie Moléculaire des Relations Plantes-Micro-Organismes, INRA-CNRS, B.P. 27, F-31326 Castanet-Tolosan Cedex, France.

  • Janice De Almeida Engler,

    1. Laboratorium voor Genetica, Department of Genetics, Flanders Interuniversity Institute for Biotechnology, Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium, and
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    • These authors have contributed equally to this work.

  • Adriana Hemerly,

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    • §

      Present address: Laboratório de Bioenergética, Departamento de Bioquimica Médica, Universidade Federal do Rio de Janeiro, CEP 21941-590, Rio de Janeiro, RJ, Brazil.

  • Paulo Ferreira,

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      Present address: Laboratório de Bioenergética, Departamento de Bioquimica Médica, Universidade Federal do Rio de Janeiro, CEP 21941-590, Rio de Janeiro, RJ, Brazil.

  • Dirk Inzé,

    1. Laboratoire Associé de l’Institut National de la Recherche Agronomique (France), Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
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  • Marc Van Montagu,

    Corresponding author
    1. Laboratorium voor Genetica, Department of Genetics, Flanders Interuniversity Institute for Biotechnology, Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium, and
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  • Godelieve Gheysen

    1. Laboratorium voor Genetica, Department of Genetics, Flanders Interuniversity Institute for Biotechnology, Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium, and
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  • In accordance with the guidelines accepted by the CPGN, the plant cyclin identified as cyc1At corresponds to Arath;CycB1;1 in the new system.

*For correspondence (fax +32 9 2645349).

Summary

Root-knot and cyst nematodes are plant parasites that induce large multinucleated feeding cells in the roots of their hosts. Cytological observations have shown that root-knot nematodes induce giant cells by cycles of mitosis without cytokinesis whereas cyst nematodes provoke cell wall degradation leading to the formation of a large syncytium. This study was intended to characterize and compare the ability of both types of nematodes to induce progression through the cell cycle. For this purpose, the expression, upon nematode infection, of two cell cycle markers was followed: a marker for division competence, the cyclin-dependent kinase cdc2a and a marker for the G2 phase, the mitotic cyclin cyc1At. For both types of nematodes, transcriptional activation of these markers was correlated with early phases of feeding cell development. Using molecular markers, it was thus possible to confirm and extend the observations of repeated mitosis in root-knot nematode-induced giant cells. Surprisingly, promoter activation of both cdc2a and cyc1At markers was also found upon cyst nematode infection, in feeding cells in which mitosis has not been clearly reported. Incorporation of tritiated thymidine in these syncytia confirms that they progress through the S phase of the cell cycle. One possibility is that cyst nematodes induce cycles of DNA endoreduplication shunting the M phase. Despite obvious differences in ontogeny, common molecular mechanisms, involving cycles of DNA endoreduplication and cdc2a and cyc1At expression, might thus be involved in the formation of a giant cell or a syncytium.

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