Comparative Proteomic Analysis of Puccinellia tenuiflora Leaves under Na₂CO₃ Stress

Abstract: Soil salt-alkalinization is a widespread environmental stress that limits crop growth and agricultural productivity. The influence of soil alkalization caused by Na₂CO₃ on plants is more severe than that of soil salinization. Plants have evolved some unique mechanisms to cope with alkali stress; however, the plant alkaline-responsive signaling and molecular pathways are still unknown. In the present study, Na₂CO₃ responsive characteristics in leaves from 50-day-old seedlings of halophyte Puccinellia tenuiflora were investigated using physiological and proteomic approaches. Comparative proteomics revealed 43 differentially expressed proteins in P. tenuiflora leaves in response to Na₂CO₃ treatment for seven days. These proteins were mainly involved in photosynthesis, stress and defense, carbohydrate/energy metabolism, protein metabolism, signaling, membrane and transport. By integrating the changes of photosynthesis, ion contents, and stress-related enzyme activities, some unique Na₂CO₃ responsive mechanisms have been discovered in P. tenuiflora. This study provides new molecular information toward improving the alkali tolerance of cereals.