Salicylic acid has a role in regulating gene expression during leaf senescence
Article first published online: 25 DEC 2001
The Plant Journal
Volume 23, Issue 5, pages 677–685, September 2000
How to Cite
Morris, K., -Mackerness, S. A. .-H., Page, T., John, C. F., Murphy, A. M., Carr, J. P. and Buchanan-Wollaston, V. (2000), Salicylic acid has a role in regulating gene expression during leaf senescence. The Plant Journal, 23: 677–685. doi: 10.1046/j.1365-313x.2000.00836.x
- Issue published online: 25 DEC 2001
- Article first published online: 25 DEC 2001
- Received 25 April 2000; revised 15 June 2000; accepted 22 June 2000.
- leaf senescence;
- signalling factors;
- gene expression;
- salicylic acid;
- cell death
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.