Key message We identified ABA- and drought-induced CtSnRK2.6 from Cynanchum thesioides; its protein localizes to the nucleus and plasma membrane. It boosts drought resistance of C. thesioides and Arabidopsis by regulating antioxidant and stress-responsive genes, while its silencing impairs C. thesioides’ drought tolerance. CtSnRK2.6 interacts with CtPP2C1/3, and CtPP2C1 binds CtPYL1/5/6. This study clarifies its core role and interaction network in the ABA pathway, laying a theoretical foundation for elucidating C. thesioides’ stress resistance mechanisms. Abstract Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a core regulator in the plant abiotic stress response pathway. In this study, we identified a Cynanchum thesioides gene CtSnRK2.6 that is homologous to Arabidopsis AtSnRK2.6, and this gene is significantly induced by drought stress and abscisic acid (ABA) treatment. Subcellular localization analysis revealed that the CtSnRK2.6 protein is localized in the nucleus and plasma membrane. Functional verification results demonstrated that overexpression of CtSnRK2.6 significantly enhances osmotic stress tolerance in yeast and drought resistance in Arabidopsis; under drought conditions, the overexpressing plants not only maintain a superior phenotype, but also exhibit significantly increased fresh weight and chlorophyll content, markedly enhanced antioxidant enzyme activity, significantly reduced accumulation of reactive oxygen species (O₂⁻, H₂O₂) and malondialdehyde (MDA), as well as significantly upregulated expression levels of stress-responsive genes. Conversely, inhibition of CtSnRK2.6 expression via Tobacco Rattle Virus (TRV)-mediated gene silencing technology significantly impairs the drought resistance of C. thesioides. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays further confirmed that CtSnRK2.6 can directly interact with CtPP2C1 and CtPP2C3; CtPP2C1 can interact with CtPYL1, CtPYL5, and CtPYL6, respectively. Taken together, this study clarifies the key role of CtSnRK2.6 in enhancing drought resistance by regulating the plant antioxidant system, and reveals its interaction network with PYL and PP2C proteins, which are core components of the ABA signaling pathway. These findings provide important theoretical support for in-depth elucidation of the stress adaptation mechanism of C. thesioides.

CtSnRK2.6 from Cynanchum thesioides confers drought stress resistance in plants

期刊论文
发表日期：

2026年2月10日

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Xiaoyao Chang,
Xiaoyan Zhang,
Fenglan Zhang,
Xiumei Huang,
Zhongren Yang

摘要

Key message

We identified ABA- and drought-induced CtSnRK2.6 from Cynanchum thesioides; its protein localizes to the nucleus and plasma membrane. It boosts drought resistance of C. thesioides and Arabidopsis by regulating antioxidant and stress-responsive genes, while its silencing impairs C. thesioides’ drought tolerance. CtSnRK2.6 interacts with CtPP2C1/3, and CtPP2C1 binds CtPYL1/5/6. This study clarifies its core role and interaction network in the ABA pathway, laying a theoretical foundation for elucidating C. thesioides’ stress resistance mechanisms.

Abstract

Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a core regulator in the plant abiotic stress response pathway. In this study, we identified a Cynanchum thesioides gene CtSnRK2.6 that is homologous to Arabidopsis AtSnRK2.6, and this gene is significantly induced by drought stress and abscisic acid (ABA) treatment. Subcellular localization analysis revealed that the CtSnRK2.6 protein is localized in the nucleus and plasma membrane. Functional verification results demonstrated that overexpression of CtSnRK2.6 significantly enhances osmotic stress tolerance in yeast and drought resistance in Arabidopsis; under drought conditions, the overexpressing plants not only maintain a superior phenotype, but also exhibit significantly increased fresh weight and chlorophyll content, markedly enhanced antioxidant enzyme activity, significantly reduced accumulation of reactive oxygen species (O₂⁻, H₂O₂) and malondialdehyde (MDA), as well as significantly upregulated expression levels of stress-responsive genes. Conversely, inhibition of CtSnRK2.6 expression via Tobacco Rattle Virus (TRV)-mediated gene silencing technology significantly impairs the drought resistance of C. thesioides. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays further confirmed that CtSnRK2.6 can directly interact with CtPP2C1 and CtPP2C3; CtPP2C1 can interact with CtPYL1, CtPYL5, and CtPYL6, respectively. Taken together, this study clarifies the key role of CtSnRK2.6 in enhancing drought resistance by regulating the plant antioxidant system, and reveals its interaction network with PYL and PP2C proteins, which are core components of the ABA signaling pathway. These findings provide important theoretical support for in-depth elucidation of the stress adaptation mechanism of C. thesioides.