CpSnRK2.7 interacts with CpPP2Cs to enhance salt tolerance via modulating oxidative stress in Cucurbita pepo.

Key message: CpSnRK2.7 interacts with CpPP2Cs and enhances salt stress tolerance in Cucurbita pepo by reducing oxidative damage, promoting proline accumulation, and maintaining photosynthetic efficiency. Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) serves as a pivotal regulator of the ABA signaling cascade and plays an essential role in plant adaptation to abiotic stress. This study elucidated the role of the CpSnRK2.7 gene in Cucurbita pepo under salt stress conditions. Overexpression of CpSnRK2.7 significantly enhanced salt tolerance by alleviating cellular oxidative damage, as demonstrated by reduced accumulation of MDA, O₂^-, and H₂O₂, while concurrently increasing antioxidant enzyme activities and proline accumulation. Importantly, CpSnRK2.7-overexpressing plants displayed faster stomatal closure and maintained higher photosynthetic efficiency in response to salt stress and ABA treatment. Given that CpSnRK2.7 expression is induced by ABA, it is postulated to function within the canonical CpPYL/PYRs-CpPP2Cs-CpSnRK2.7 signaling module. Protein-protein interaction analysis via the STRING database and yeast two-hybrid assays revealed direct interactions between CpSnRK2.7 and CpPP2C1 as well as CpPP2C3. Notably, the interaction between CpPP2C1 and multiple CpPYL/PYRs was significantly enhanced following ABA treatment. Taken together, these findings indicate that CpSnRK2.7 plays a pivotal role in salt stress adaptation through ABA-mediated signaling and identifies potential targets for enhancing crop tolerance to salinity.