CBL-Interacting Protein Kinase 2 Improves Salt Tolerance in Soybean (Glycine max L.)

Abstract

Salt stress severely limits soybean production worldwide. Calcineurin B-like protein-interacting protein kinases (CIPKs) play a pivotal role in a plant’s adaption to salt stress. However, their biological roles in soybean adaption to salt stress remain poorly understood. Here, the GmCIPK2 expression was increased by NaCl and hydrogen peroxide (H2O2). GmCIPK2-overexpression Arabidopsis and soybean hairy roots displayed improved salt tolerance, whereas the RNA interference of hairy roots exhibited enhanced salt sensitivity. Further analyses demonstrated that, upon salt stress, GmCIPK2 enhanced the proline content and antioxidant enzyme activity and decreased the H2O2 content, malondialdehyde (MDA) content, and Na+/K+ ratios in soybean. Moreover, GmCIPK2 promoted the expression of salt- and antioxidant-related genes in response to salt stress. Moreover, the GmCIPK2-interacting sensor, GmCBL4, increased the salt tolerance of soybean hairy roots. Overall, these results suggest that GmCIPK2 functions positively in soybean adaption to salt stress.