GmPP2C113, a Soybean Protein Phosphatase, Positively Regulates Both Salt Tolerance and Symbiotic Nodulation

Protein phosphatase type 2C (PP2C) family members are key signaling hubs in plants, but their roles in mediating the trade-off between stress adaptation and symbiotic interactions remain unclear. This study aimed to investigate the function of soybean GmPP2C113, which was identified as a potential regulator linking salt stress responses and symbiotic nodulation, in coordinating these two biological processes in soybean (Glycine max).

The GmPP2C113 gene was cloned, and its subcellular localization, transcriptional activity, and protein interactions were characterized. Expression patterns under salt stress and rhizobial inoculation were analyzed. The biological role of GmPP2C113 was assessed using transgenic soybean plants overexpressing GmPP2C113. GmPP2C113 was localized in the nucleus and possessed transcriptional activation capability and interacted with GmPP2C47. Its expression was strongly induced by salt stress and by rhizobial infection, with the highest levels detected in mature nodules. Overexpression of GmPP2C113 significantly enhanced salt tolerance, upregulated stress-related genes, increased nodule numbers, and promoted symbiotic nodulation under salt stress by inducing nodulation marker genes.

These results identify GmPP2C113 as a positive modulator of salt tolerance and reveal its novel role as a molecular node that sustains symbiotic nodulation under salt stress. This provides insight into the coordinated regulation of stress adaptation and symbiosis in soybean.