GmCIPK29 positively regulates drought tolerance through involvement in the reactive oxygen species scavenging and abscisic acid signaling pathway

The calcineurin B-like protein (CBL)-CBL interacting protein kinase (CIPK) signaling pathway is important for plants to response to environmental stresses. However, few academic studies have elucidated CIPKs in soybean, and the mechanism by which CIPKs promote drought resistance is unclear. In this study, the GmCIPK29 was found to interact with GmCBL1, expression analysis and GUS staining showed that transcript level of GmCIPK29 was induced by drought and exogenous abscisic acid (ABA). GmCIPK29 increased ABA sensitivity and conferred drought resistance in Arabidopsis. Moreover, GmCIPK29-overexpression (GmCIPK29-OE) Arabidopsis plants showed increased stomatal movement and reduced water loss under water deficit condition, and the content of malondialdehyde (MDA) decreased under drought stress in the GmCIPK29-OE soybean hairy roots. In addition, soybean hairy roots with GmCIPK29 knocked down via RNA interference showed higher levels of reactive oxygen species (ROS) under water deficit conditions. Gene expression analysis showed that stress-related genes, including GmCAT5, GmPOD4, and GmNCED1, were induced in GmCIPK29-OE soybean plants under drought stress. This study revealed an important role of soybean GmCIPK29 in responses to abiotic stress and these findings provide a foundation for additional inquiry into the complex mechanisms of the CBL-CIPK signaling pathway.