Fatty Acids Unsaturation of Membrane Lipids is Involved in the Tolerance to Salt Stress

Abstract

Cyanobacteria exhibit considerable tolerance to salt stress and are useful for studies of acclimation and tolerance to such stress. In a previous study we isolated a desA−/desD− mutant strain of Synechocystis sp. PCC 6803 in which the desA and desD genes for the Δl2 and Δ6 desaturases, respectively, had been inactivated by targeted mutagenesis (1). The desA−/desD− cells contain monounsaturated but not polyunsaturated fatty acids, whereas wild-type cells contain polyunsaturated fatty acids such as di-, tri-, and tetraunsaturated fatty acids (2,3). In the present study, we investigated the contribution of the unsaturation of fatty acids in membrane lipids to tolerance to salt stress by comparing desA − /desD − cells to wild-type cells of Synechocystis sp. PCC 6803. We demonstrated that the unsaturation of fatty acids is associated with the ability of the photosynthetic machinery to tolerate salt stress.