Abscisic acid confers salinity tolerance in Chlamydomonas reinhardtii at different stages of its life cycle

Abstract

The effect of abscisic acid (ABA) to increase the osmotolerance of the freshwater microalga Chlamydomonas reinhardtii at its different stages of life cycle was investigated. Exogenously added ABA enhanced the growth and photosynthesis of C. reinhardtii during the vegetative stage. The hormone also increased the tolerance of this alga to oxidative stress during gamete formation under nutrient depletion and high salinity, as it supported their survival for a longer period. We show that the level of reactive oxygen species (ROS) generated in the ABA-treated cells was significantly less than that in the untreated cells under inhibiting NaCl concentrations. Cell size examination showed that ABA prevents cells from forming palmella when exposed to high salinity. All together, these results suggest that ABA increases the tolerance of C. reinhardtii to salt stress conditions.