Arabidopsis MPK6 is involved in cell division plane control during early root development, and localizes to the pre-prophase band, phragmoplast, trans-Golgi network and plasma membrane

Authors

  • Jens Müller,

    1. Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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    • These two authors contributed equally to this work.

  • Martina Beck,

    1. Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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    • These two authors contributed equally to this work.

  • Ursula Mettbach,

    1. Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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  • George Komis,

    1. Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
    2. Department of Biology, University of Athens, GR15784 Athens, Greece
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  • Gerd Hause,

    1. Martin-Luther-Universität Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120 Halle, Germany
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  • Diedrik Menzel,

    1. Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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  • Jozef Šamaj

    Corresponding author
    1. Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
    2. Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
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For correspondence (fax +49 228 73 9004; e-mail jozef.samaj@uni-bonn.de).

Summary

The proper spatial and temporal expression and localization of mitogen-activated protein kinases (MAPKs) is essential for developmental and cellular signalling in all eukaryotes. Here, we analysed expression, subcellular localization and function of MPK6 in roots of Arabidopsis thaliana using wild-type plants and three mpk6 knock-out mutant lines. The MPK6 promoter showed two expression maxima in the most apical part of the root meristem and in the root transition zone. This expression pattern was highly consistent with ‘no root’ and ‘short root’ phenotypes, as well as with ectopic cell divisions and aberrant cell division planes, resulting in disordered cell files in the roots of these mpk6 knock-out mutants. In dividing root cells, MPK6 was localized on the subcellular level to distinct fine spots in the pre-prophase band and phragmoplast, representing the two most important cytoskeletal structures controlling the cell division plane. By combining subcellular fractionation and microscopic in situ and in vivo co-localization methods, MPK6 was localized to the plasma membrane (PM) and the trans-Golgi network (TGN). In summary, these data suggest that MPK6 localizing to mitotic microtubules, secretory TGN vesicles and the PM is involved in cell division plane control and root development in Arabidopsis.

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