Salicylic acid has a role in regulating gene expression during leaf senescence

Plant J. 2000 Sep;23(5):677-85. doi: 10.1046/j.1365-313x.2000.00836.x.


Leaf senescence is a complex process that is controlled by multiple developmental and environmental signals and is manifested by induced expression of a large number of different genes. In this paper we describe experiments that show, for the first time, that the salicylic acid (SA)-signalling pathway has a role in the control of gene expression during developmental senescence. Arabidopsis plants defective in the SA-signalling pathway (npr1 and pad4 mutants and NahG transgenic plants) were used to investigate senescence-enhanced gene expression, and a number of genes showed altered expression patterns. Senescence-induced expression of the cysteine protease gene SAG12, for example, was conditional on the presence of SA, together with another unidentified senescence-specific factor. Changes in gene expression patterns were accompanied by a delayed yellowing and reduced necrosis in the mutant plants defective in SA-signalling, suggesting a role for SA in the cell death that occurs at the final stage of senescence. We propose the presence of a minimum of three senescence-enhanced signalling factors in senescing leaves, one of which is SA. We also suggest that a combination of signalling factors is required for the optimum expression of many genes during senescence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / physiology
  • Blotting, Northern
  • Gene Expression Regulation, Plant*
  • Mutation
  • Plant Leaves / physiology*
  • Salicylic Acid / metabolism*
  • Signal Transduction


  • Salicylic Acid