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

Planta. 2006 Aug;224(3):556-68. doi: 10.1007/s00425-006-0243-y. Epub 2006 Mar 3.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anion Transport Proteins / genetics
  • Anion Transport Proteins / metabolism
  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Carbon / metabolism
  • Cluster Analysis
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism
  • Fructose / metabolism*
  • Fructose / physiology
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant*
  • Glucose / metabolism*
  • Glucose / physiology
  • Glutamate-Ammonia Ligase / genetics
  • Glutamate-Ammonia Ligase / metabolism
  • Hexokinase / genetics
  • Hexokinase / metabolism
  • Mutation
  • Nitrogen / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Pancreatitis-Associated Proteins
  • Plant Leaves / genetics
  • Plant Leaves / growth & development
  • Plant Leaves / metabolism
  • Signal Transduction
  • Transcription Factors / genetics
  • Transcription Factors / metabolism

Substances

  • Anion Transport Proteins
  • Arabidopsis Proteins
  • PAP1 protein, Arabidopsis
  • PAP2 protein, Arabidopsis
  • Pancreatitis-Associated Proteins
  • REG3A protein, human
  • Transcription Factors
  • nitrate transporters
  • Fructose
  • Carbon
  • Hexokinase
  • SAG12 protein, Arabidopsis
  • Cysteine Endopeptidases
  • Glutamate-Ammonia Ligase
  • Glucose
  • Nitrogen