CPK12 and Ca 2+ -mediated hypoxia signaling.

Hypoxia triggers reactive oxygen species (ROS)-induced elevation in cytoplasmic calcium (Ca 2+ ) in the plant cells. Calcium-dependent protein kinase 12 (CPK12) acts as a sensor to recognize the Ca 2+ signature and is activated by autophosphorylation. Then, the CPK12 moves into the nucleus with the help of phosphatidic acid (PA) and phosphorylates ERF-VII family proteins that activate hypoxia signaling and response. The study provides a novel mechanism of hypoxia signaling in plants. Moreover, the mechanism of hypoxia-specific Ca 2+ signature generation remains elusive.