Planta

, Volume 224, Issue 3, pp 556–568

Effect of sugar-induced senescence on gene expression and implications for the regulation of senescence in Arabidopsis

  • Nathalie Pourtau
  • Richard Jennings
  • Elise Pelzer
  • Jacqueline Pallas
  • Astrid Wingler
Original Article

DOI: 10.1007/s00425-006-0243-y

Cite this article as:
Pourtau, N., Jennings, R., Pelzer, E. et al. Planta (2006) 224: 556. doi:10.1007/s00425-006-0243-y

Abstract

There has been some debate whether leaf senescence is induced by sugar starvation or by sugar accumulation. External supply of sugars has been shown to induce symptoms of senescence such as leaf yellowing. However, it was so far not clear if sugars have a signalling function during developmental senescence. Glucose and fructose accumulate strongly during senescence in Arabidopsis thaliana (L.) Heynh. leaves. Using Affymetrix GeneChip analysis we determined the effect of sugar-induced senescence on gene expression. Growth on glucose in combination with low nitrogen supply induced leaf yellowing and changes in gene expression that are characteristic of developmental senescence. Most importantly, the senescence-specific gene SAG12, which was previously thought to be sugar-repressible, was induced over 900-fold by glucose. Induction of SAG12, which is expressed during late senescence, demonstrates that processes characteristic for late stages are sugar-inducible. Two MYB transcription factor genes, PAP1 and PAP2, were identified as senescence-associated genes that are induced by glucose. Moreover, growth on glucose induced genes for nitrogen remobilisation that are typically enhanced during developmental senescence, including the glutamine synthetase gene GLN1;4 and the nitrate transporter gene AtNRT2.5. In contrast to wild-type plants, the hexokinase-1 mutant gin2-1 did not accumulate hexoses and senescence was delayed. Induction of senescence by externally supplied glucose was partially abolished in gin2-1, indicating that delayed senescence was a consequence of decreased sugar sensitivity. Taken together, our results show that Arabidopsis leaf senescence is induced rather than repressed by sugars.

Keywords

ArabidopsisGlucose signallingHexokinase-1Nitrogen remobilisationSAG12Senescence

Abbreviations

Fv/Fm

Maximum photosynthetic efficiency

HNG

High nitrogen plus glucose

LN

Low nitrogen

LNG

Low nitrogen plus glucose

SAG

Senescence-associated gene

Supplementary material

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Nathalie Pourtau
    • 1
  • Richard Jennings
    • 1
  • Elise Pelzer
    • 1
  • Jacqueline Pallas
    • 2
  • Astrid Wingler
    • 1
  1. 1.Department of BiologyUniversity College LondonLondonUK
  2. 2.Bloomsbury Centre for BioinformaticsUniversity College LondonLondonUK