Narrowing Down On CIPK16 Orthologues: A Gene Involved In Enhanced Salt Tolerance

Calcineurin B-Like Protein Interacting Protein Kinases (CIPKs) are key regulators of pre-transcriptional and post-translational responses to abiotic stresses. Many plant species have numerous forms of CIPKs, which appear to have very specific roles during abiotic stress. From a forward genetics screen, Arabidopsis thaliana CIPK16 (AtCIPK16) has been previously identified as an important gene responsible for reduced shoot salt accumulation and improved salinity tolerance in Arabidopsis and transgenic barley. However, the existence of AtCIPK16 homologues in cereals and the mode of action of AtCIPK16 in them are still unknown. Thus, this study aimed to understand the prevalence of CIPK16, and in return find an AtCIPK16 orthologue in cereals. A phylogenetic analysis has been performed on CIPK genes obtained from several species related to A. thaliana and cereal crops. The resulting phylogenetic tree revealed insights into the evolution of CIPK16 which has important consequences for breeding salt tolerance in cereal crops. One particular observation was that the clade including AtCIPK16 had a sister clade which contained two segmentally duplicated genes AtCIPK5 and AtCIPK25. Furthermore, we find AtCIPK16 contains an indel which is conserved in Brassicaceae.