Effects of Rbp3 on lipid peroxidation and salt tolerance in Synechocystis sp. PCC 6803.

RNA-binding proteins (Rbps) are involved in many post-transcriptional regulation processes. As previously shown, inactivation of rbp3 in Synechocystis sp. PCC 6803 significantly decreased the stability of acyl-lipid desaturase (des) mRNAs and the degree of unsaturation of membrane lipids. In comparison to the wild type, the rbp3 mutant produced less lipid peroxides under cold stress and showed greater inhibition of photosynthesis/respiration activities by salt stress. Overexpression of desA partially restored levels of lipid peroxidation and salt tolerance in the mutant. Effects of Rbp3 on lipid peroxidation and salt tolerance appears to be directly related to the change of degree of lipid unsaturation.