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The Arabidopsis GSQ5/DOG1 Cvi allele is induced by the ABA-mediated sugar signalling pathway, and enhances sugar sensitivity by stimulating ABI4 expression

Authors

  • Sheng Teng,

    1. Molecular Plant Physiology Group, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht
    2. Centre for BioSystems Genomics CBSG2012, P.O. Box 98, 6700 AB Wageningen, the Netherlands
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    • Present address: Shanghai Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, The Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.

  • Sara Rognoni,

    1. Molecular Plant Physiology Group, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht
    2. Department of Crop Plant Biology, University of Pisa, via Mariscoglio 34, I-56124 Pisa, Italy
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  • Leónie Bentsink,

    1. Molecular Plant Physiology Group, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht
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  • Sjef Smeekens

    Corresponding author
    1. Molecular Plant Physiology Group, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht
    2. Centre for BioSystems Genomics CBSG2012, P.O. Box 98, 6700 AB Wageningen, the Netherlands
      *(fax +313 02 53 2837; e-mail j.c.m.smeekens@uu.nl).
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*(fax +313 02 53 2837; e-mail j.c.m.smeekens@uu.nl).

Summary

ABI4 encodes an AP2 family transcription factor that is a central regulator in sugar responsive gene expression in plants. Sugar-induced ABI4 regulates plant genes essential for photosynthesis, and carbon, nitrogen and lipid metabolism. ABI4 activity is induced via the ABA-mediated sugar signalling pathway, which is initiated by the glucose sensing protein hexokinase. Natural variation in sugar sensitivity was used to identify new loci involved in sugar signalling. Five quantitative trait loci (QTLs) for glucose sensitivity (GSQ1–GSQ5) were identified in a Ler/Cvi recombinant inbred line (RIL) population. The GSQ3, GSQ4 and GSQ5 loci are positioned in regions not previously associated with known sugar-sensing genes. GSQ5 was fine mapped and cloned using a candidate-gene approach. The GSQ5 locus was shown to encode the DELAY OF GERMINATION 1 (DOG1) gene. DOG1 was previously identified as a major locus in seed dormancy control. Glucose addition induced the expression of the GSQ5/DOG1 Cvi allele, whereas the Ler and Col alleles did not respond to glucose. Positive feedback was observed between the ABA-mediated sugar signalling pathway and the GSQ5/DOG1 Cvi allele. Expression of the GSQ5/DOG1 Cvi allele requires the ABA-mediated sugar signalling pathway, of which ABI4 is an important component. In addition, sugar induction of ABI4 was promoted by the GSQ5/DOG1 Cvi allele.

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