Journal of Proteomics & Bioinformatics
Open Access

Abstract

Identification of NaHCO3 Stress Responsive Proteins in Dunaliella salina HTBS using iTRAQ-based Analysis

Yue Zhao, Yuyong Hou, Zhiyong Liu, Shulin Chen and Fangjian Chen

Converting CO₂ to HCO₃^- through CO₃^2- as a carbon source for microalgae growth offers an alternative route for CO₂ fixation. There, however, are concerns over algae growth inhibition caused by high HCO₃^- concentration. The exact mechanism of the microalgae response to NaHCO3 stress also needs further understanding. This study evaluated the effect of high HCO₃^- on enhancing growth of algae Dunaliella salina HTBS by identifying a series of differentially expressed proteins in responding to NaHCO₃ stress using iTRAQ (isobaric tags for relative and absolute quantitation) assay. Results showed that HTBS featured with adaptability to broad HCO₃^- concentrations (25 to 70 g/L NaHCO₃). The specific growth rate (OD₇₅₀) reached 1.08 day⁻¹ at 25 g/L NaHCO3. A total of 196 proteins were observed responsive to 25 g/L NaHCO₃ stress. Among these proteins, 84 proteins were up-regulated, whereas 112 down-regulated. Gene Ontology and KEGG pathway analysis showed that most of the up-regulated proteins were involved in transport and respiratory metabolism, and that the majority of the down-regulated proteins accounted for fatty acid oxidative metabolism and photosynthesis. These results provide new insights into the regulation of HCO₃^- tolerant mechanism in Dunaliella salina HTBS. These findings may be applicable to genetic engineering microalgae for high CO₂ fixation efficiency.