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Abstract
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To gain a better understanding of molecular and biochemical events involved in light intensity adaptations of Dunaliella salina, we studied the expression of phytoen synthase ( psy ) gene; pigments, carbohydrates, proteins and lipids accumulation under two light intensities. The cells were pre - cultured under 50 µmol photon m - 2 s - 1 light intensity and then transferred to two different light intensities of 200 and 1000 µmol photon m - 2 s - 1 . The psy gene expression in high light (1000 µ mol photon m - 2 s - 1 ) decreased and rema ined fairly constant until 48 h however, a more decrease was appeared under the low light (200 µ mol photon m - 2 s - 1 ). After 2 weeks cultivation, the high light led to a considerable decrease of Chl a and Chl b contents, and an increase in carotenoids/total chlorophylls and Chl a /Chl b ratios. Total, soluble and non - soluble (starch) carbohydrates; proteins and lipids contents of cells were increased under the high light c onditions. The results suggest that D. salina cells can have light intensity dependent adjustments in gene expressions, photosynthesis apparatus function , and structure as well as biochemical cell composition.
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