A salt-induced chloroplast protein in Dunaliella salina (Chlorophyta)

The unicellular green alga Dunaliella salina Teod. is halophilic and wall-less. The cell acclimates to osmotic stresses by accumulation or degradation of glycerol. To investigate other mechanisms involved in its physiological recovery following hyperosmotic shocks, protein profiles from cells grown in various salinities were compared. A 13-kDa protein (P13) accumulated when cells were subjected to drastic hyperosmotic shock. From our results with antibiotic-treated cells and purified chloroplasts, we believe that this component results from de novo translation in chloroplasts. The solubility of P13 was strongly promoted by Triton X-100. Its accumulation was correlated with the recovery of photosynthesis.