Characterization of the calcineurin B-Like (CBL) gene family in maize and functional analysis of ZmCBL9 under abscisic acid and abiotic stress treatments

•We identified 12 CBL (calcineurin B-like protein) genes in maize.•Maize CBLs (ZmCBLs) have EF-hand domains, which function in Ca2+ signaling.•Overexpression of ZmCBL9 increased ABA and osmotic stress tolerance in Arabidopsis.•Eight stress-responsive ZmCIPKs interacted with ZmCBL9.•ZmCBL9 interacts with ZmCIPKs to help regulate abiotic stress and ABA signaling. In plants, calcineurin B-like proteins (CBLs) play crucial roles in regulating calcium-signaling in response to various abiotic stresses by interacting with specific CBL-interacting protein kinases (CIPKs). However, the identities and functions of CBL gene family members in maize are largely unknown. Here, we identified from the maize genome 12 CBL genes. All 12 CBLs have conserved EF-hand domains, and half harbor myristoylation motifs. We further characterized the function of one CBL gene, ZmCBL9, which can be induced by salt, dehydration, glucose and abscisic acid (ABA) treatments. Overexpression of ZmCBL9 enhanced resistance or tolerance to ABA, glucose, salt and osmotic stress in Arabidopsis and complemented the hypersensitive phenotype of the Arabidopsis cbl9 mutant in response to ABA and abiotic stress. The ZmCBL9 gene negatively regulates the expression of genes in the ABA signaling, biosynthesis and catabolism pathways. Moreover, the ZmCBL9 protein is found to interact with eight maize CIPKs and these ZmCIPK genes were up-regulated by different stress treatments, including salt, dehydration, glucose, low potassium and ABA. These results suggest that ZmCBL9 may interact with various ZmCIPKs to regulate the abiotic stress and ABA response signaling in plants.