CPK28-NLP7 module integrates cold-induced Ca 2+ signal and transcriptional reprogramming in Arabidopsis .

Exposure to cold triggers a spike in cytosolic calcium (Ca) that often leads to transcriptional reprogramming in plants. However, how this Ca signal is perceived and relayed to the downstream cold signaling pathway remains unknown. Here, we show that the CALCIUM-DEPENDENT PROTEIN KINASE 28 (CPK28) initiates a phosphorylation cascade to specify transcriptional reprogramming downstream of cold-induced Ca signal. Plasma membrane (PM)-localized CPK28 is activated rapidly upon cold shock within 10 seconds in a Ca-dependent manner. CPK28 then phosphorylates and promotes the nuclear translocation of NIN-LIKE PROTEIN 7 (NLP7), a transcription factor that specifies the transcriptional reprogramming of gene sets in response to Ca, thereby positively regulating plant response to cold stress. This study elucidates a previously unidentified mechanism by which the CPK28-NLP7 regulatory module integrates cold-evoked Ca signal and transcriptome and thus uncovers a key strategy for the rapid perception and transduction of cold signals from the PM to the nucleus.