Alkali-salinity NaHCO3-responsive mechanisms in leaves from halophyte Puccinellia tenuiflora revealed from physiological and comparative proteomic analysis

Alkali-salinity is a major abiotic stress that limits plant growth and productivity. Studying mechanisms of alkali-salinity tolerance in halophytic plants will provide valuable information for underlying plant alkali-salinity tolerance. Puccinellia tenuiflora is considered as an ideal model plant for studying the alkali-salinity tolerant mechanisms in plants. In this study, the NaHCO3-responsive molecular mechanisms in P. tenuiflora leaves were investigated using a combined physiological and proteomic approaches. Our results implied some specific NaHCO3-responsive mechanisms in leaves from P. tenuiflora. They are (1) reduction of photosynthesis attributed to the decrease of the abundance of Calvin cycle enzymes, (2) accumulation of Na+ and K+ caused ion-specific stress, (3) accumulation of proline, soluble sugar and betaine enhanced the ability of osmotic regulation, (4) diverse reactive oxygen species (ROS) scavenging mechanisms under different NaHCO3 concentrations, and (5) alternative protein synthesis and processing strategies in chloroplast and cytoplasm. All these provide important evidence for understanding NaHCO3-responsive mechanisms in P. tenuiflora.