Low-temperature-induced beta-carotene and fatty acid synthesis, and ultrastructural reorganization of the chloroplast in Dunaliella salina (Chlorophyta)

Abstract

The effect of suboptimal growth temperature on beta-carotene and fatty acid biosynthesis, and on the ultrastructural reorganization of the chloroplast, in the green unicellular alga Dunaliella salina has been studied. A decrease from the optimal temperature for growth (30 degrees C) to suboptimal (18 degrees C) temperatures induced beta-carotene synthesis and increased lipid content in D, salina cells, thereby promoting the formation of lipid-carotene globules in the chloroplast periphery. The content of polyunsaturated fatty acids was higher in cells cultured at low temperature. Results suggest that the induction of carotenogenesis and accumulation of polyunsaturated fatty acids are mechanisms of acclimation to unfavourable environmental conditions for growth.