The Arabidopsis SUCROSE UNCOUPLED-6 gene is identical to ABSCISIC ACID INSENSITIVE-4: involvement of abscisic acid in sugar responses

Authors

  • Casper Huijser,

    Corresponding author
    1. Department of Molecular Plant Physiology and
    2. Department of Molecular Genetics, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands, and
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  • Anne Kortstee,

    1. Department of Molecular Plant Physiology and
    2. Department of Molecular Genetics, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands, and
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  • Jónatas Pego,

    1. Department of Molecular Plant Physiology and
    2. Department of Molecular Genetics, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands, and
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    • Present address: Biology Department, Minho University, Gualtar Campus, 4710-057 Braga, Portugal.

  • Peter Weisbeek,

    1. Department of Molecular Genetics, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands, and
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  • Ellen Wisman,

    1. Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
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    • Present address: MSU-DOE, Plant Research Laboratory, Michigan State, University, 310 Plant Biology, East Lansing, MI 48824-1312, USA.

  • Sjef Smeekens

    1. Department of Molecular Plant Physiology and
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For correspondence (fax +31 30 2513655; e-mail j.c.m.smeekens@bio.uu.nl).

Summary

In plants, sugars act as signalling molecules that control many aspects of metabolism and development. Arabidopsis plants homozygous for the recessive sucrose uncoupled-6 (sun6) mutation show a reduced sensitivity to sugars for processes such as photosynthesis, gene expression and germination. The sun6 mutant is insensitive to sugars that are substrates for hexokinase, suggesting that SUN6 might play a role in hexokinase-dependent sugar responses. The SUN6 gene was cloned by transposon tagging and analysis showed it to be identical to the previously described ABSCISIC ACID INSENSITIVE-4 (ABI4) gene. Our analysis suggests the involvement of abscisic acid and components of the abscisic acid signal transduction cascade in a hexokinase-dependent sugar response pathway. During the plant life cycle, SUN6/ABI4 may be involved in controlling metabolite availability in an abscisic acid- and sugar-dependent way.

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