Plant Molecular Biology

, Volume 63, Issue 2, pp 195–206

ABI4 mediates the effects of exogenous trehalose on Arabidopsis growth and starch breakdown

  • Matthew Ramon
  • Filip Rolland
  • Johan M. Thevelein
  • Patrick Van Dijck
  • Barbara Leyman
Article

DOI: 10.1007/s11103-006-9082-2

Cite this article as:
Ramon, M., Rolland, F., Thevelein, J.M. et al. Plant Mol Biol (2007) 63: 195. doi:10.1007/s11103-006-9082-2

Abstract

The disaccharide trehalose has dramatic effects on plant metabolism, growth and development. Arabidopsis seedlings grown on trehalose-containing medium without sucrose display increased expression of the starch synthesis gene ApL3, hyper-accumulation of starch in the cotyledons and inhibition of root growth. Here we show that the ABI4 transcription factor mediates the effects of trehalose on starch metabolism and growth, independently of abscisic acid (ABA) synthesis and hexokinase (HXK1) signaling. Surprisingly, although the abi4 mutation partially rescued trehalose inhibition of root elongation, ApL3 expression levels were still enhanced. Gene expression analysis suggests that trehalose affects both starch synthesis and starch breakdown. The expression of genes involved in starch breakdown, such as SEX1 and the β-amylase gene BMY8/BAM3, was strongly down-regulated in WT plants grown on trehalose but not in abi4 mutants. Addition of trehalose to liquid-grown WT seedlings also significantly reduced SEX1 expression after 6 h. Bypassing the need for starch breakdown by growth in continuous light or addition of sucrose rescued root growth on trehalose medium similar to the abi4 mutation. These results suggest that inhibition of starch mobilization rather than increased synthesis is involved in growth inhibition by exogenous trehalose. Trehalose also significantly enhanced ABI4 expression but reduced its sucrose induction, providing a possible molecular mechanism for the trehalose effect on plant gene expression and growth.

Keywords

Trehalose ABI4 Starch breakdown Arabidopsis thaliana Root elongation 

Abbreviations

ABA

abscisic acid

aba2

abscisic acid synthesis defective 2

abi1

abscisic acid insensitive 1

abi4

abscisic acid insensitive 4

ApL3

ADP-glucose pyrophosphorylase

gin2

glucose insensitive 2

HXK1

hexokinase 1

TPS

trehalose-6-phosphate synthase

TPP

trehalose-6-phosphate phosphatase

T6P

trehalose-6-phosphate

SEX1

STARCH EXCESS1

val A

validamycin A

Supplementary material

11103_2006_9082_MOESM1_ESM.pdf (32 kb)
Supplementary material

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Matthew Ramon
    • 1
  • Filip Rolland
    • 1
  • Johan M. Thevelein
    • 1
  • Patrick Van Dijck
    • 1
  • Barbara Leyman
    • 1
    • 2
  1. 1.Katholieke Universiteit Leuven and Department of Molecular Microbiology, VIBLaboratory of Molecular Cell Biology, Institute of Botany and MicrobiologyLeuven-HeverleeBelgium
  2. 2.VIB HeadquartersGhentBelgium

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