CDPK-mediated signalling pathways: specificity and cross-talk.

Plants are constantly exposed to environmental changes and have to integrate a variety of biotic and abiotic stress stimuli. Calcium-dependent protein kinases (CDPKs) are implicated as important sensors of Ca2+ flux in plants in response to these stresses. CDPKs are encoded by multigene families, and expression levels of these genes are spatially and temporally controlled throughout development. In addition, a subset of CDPK genes responds to external stimuli. Biochemical evidence supports the idea that CDPKs are involved in signal transduction during stress conditions. Furthermore, loss-of-function and gain-of-function studies revealed that signalling pathways leading to cold, salt, drought or pathogen resistance are mediated by specific CDPK isoforms