Oral Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

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.