Calcium-dependent protein kinase gene ZmCPK12 from maize confers tolerance to drought and salt stresses in transgenic plants

Calcium-dependent protein kinases (CDPKs) are important calcium sensors in calcium-mediated signal transductions in plant cells. Increasing evidence shows that CDPKs play vital regulatory roles in abiotic stress responses in plants. We isolated the ZmCPK12 gene encoding a CDPK from maize seedlings. The predicted ZmCPK12 protein contains a typical conserved CDPK structure, a Ser/Thr kinase domain and four EF-hand domains. A ZmCPK12::hGFP fusion protein was localized in the cytoplasm and nucleus when introduced into Arabidopsis mesophyll protoplasts. ZmCPK12 transcription was highly activated by drought and salt in maize seedlings. Isolation of the ZmCPK12 promoter revealed some cis-acting elements that respond to stress. Overexpression of ZmCPK12 improved plant survival rates under drought conditions and enhanced chlorophyll content in transgenic Arabidopsis plants subjected to salt stress. This study revealed that ZmCPK12 is involved in response to environmental stresses, and that ZmCPK12 can be used for genetic improvement in tolerance to environmental stresses of plants.