Parallel analysis of proteins in brown seaweed Sargassum fusiforme responding to hyposalinity stress

摘要

The intertidal seaweed Sargassum fusiforme shows remarkable tolerances to freshwater immersion, which made experienced cultivators quite convenient to control epiphytic algae that would limit the massive aquaculture production. Here, we performed biochemical and physiological analyses and comparative proteomics to investigate the molecular mechanisms of the hyposalinity-stress-tolerance in S. fusiforme. Our results showed that in the initial period of freshwater immersion, mineral fraction and inorganic anion may be lost much faster than other soluble contents. H2O2 accumulation occurred immediately and the antioxidant system was efficiently activated during freshwater immersion. Comparative proteomic analysis revealed 51 differentially expressed protein spots in S. fusiforme, most of which were enzymes involved in photosynthesis, carbohydrate metabolism and energy metabolism. The one-hour's-freshwater-immersion negatively affected the metabolic activity of S. fusiforme, as synthesis of most key metabolic enzymes were inhibited in varying degrees, with only a few exceptions, e.g., phosphomannomutase, which is related to precursor synthesis of cell wall polysaccharides.