Soil alkalization is one of the majors threatens that affect plant production and ecological environment. Saline-alkali stress causes oxidative stress on plants, and seriously affect plant growth and development. Halophyte alkaligrass (Puccinellia tenuiflora) is an outstanding pasture with strong tolerance to salt and alkali stresses. In this study, the molecular mechanisms of Na2CO3 response in alkaligrass were analyzed using redox proteomics and molecular genetics approaches. Besides, the activities of enzymes in reactive oxygen species (ROS) scavenging system were detected in alkaligrass leaves and roots. The abundances patterns and redox states of Na2CO3-responsive proteins indicated that Ca2+-mediated kinase signaling, membrane trafficking, cytoskeletal remodeling, ROS homeostasis, stress and defense, gene expression and protein turnover, carbohydrate metabolism, amino acid metabolism were pivotal to Na2CO3 adaptation in alkaligrass.
Moreover, two proteins were proved to be crucial in alkaligrass under the Na2CO3 stress. The developmentally regulatory plasma membrane polypeptide protein (DREPP) were involved in the regulation of binding phosphatidylinositol phosphate (PtdInsPs) and regulation of the cytoskeletal structure. Overexpression of PutDREPP in wild-type Arabidopsis enhanced the root resistance to saline-alkali stresses. And the expression of PutDREPP were increased significantly in response to Na2CO3, NaCl, NaHCO3 and H2O2 stresses. Besides, cysteine-rich repeat secretory protein 55 (CRRSP55) modulates cell-to-cell trafficking, and it has the conserved active motif C-X8-C-X2-C of RLK. The Cys78 and Cys214 of PutCRRSP55 was oxidized under Na2CO3 stress, which would affect PutCRRSP55 protein function. The expression of PutCRRSP55 were increased significantly in alkaligrass in response to Na2CO3, NaCl, and H2O2 stresses. This provides new clues for further study on the regulation network of plant saline-alkali stress response, and also provide important information for the breeding of salt-tolerant crops.