Identification of calmodulin-dependent NAD+ kinase that sustains the elicitor-induced oxidative burst (Plant Phys)

When pathogens attack, one line of defense is the production of a burst of reactive oxygen species (ROS) which triggers additional defences. ROS is produced by the action of NADPH oxidases, which require NADPH as a substrate; NADPH is derived from NADP⁺, but where does this come from? Previous studies have pointed to its production involving a (CaM)/Ca2+- dependent NAD⁺ kinase, but the responsible protein hasn’t been identified. Now, through proteomic and molecular approaches, Dell’Aglio et al. have identified NAD kinase-CaM dependent (NADKc). NADKc is associated with the periphery of the mitochondria, activated in response to elicitor treatment, and contributes to the pool of NADP⁺ required for ROS production. Genes encoding this protein are found in most but not all photosynthetic organisms. (Summary by Mary Williams) Plant Physiol. 10.1104/pp.19.00912