- I. Introduction 250
- II. Increases in free cellular [Ca2+]: an early and key event in plant defence signalling 251
- III. Relationships between [Ca2+]cyt increases and defence-signalling pathways 256
- IV. Calcium targets involved in plant defence reactions 258
- V. Concluding remarks 262
In plant cells, the calcium ion is a ubiquitous intracellular second messenger involved in numerous signalling pathways. Variations in the cytosolic concentration of Ca2+ ([Ca2+]cyt) couple a large array of signals and responses. Here we concentrate on calcium signalling in plant defence responses, particularly on the generation of the calcium signal and downstream calcium-dependent events participating in the establishment of defence responses with special reference to calcium-binding proteins.