Salt induced oxidative stress alters physiological, biochemical and metabolomic responses of green microalga Chlamydomonas reinhardtii

Soufiane Fal; Abderahim Aasfar; Reda Rabie; Abelaziz Smouni; Hicham El Arroussi

doi:10.1016/j.heliyon.2022.e08811

Salt induced oxidative stress alters physiological, biochemical and metabolomic responses of green microalga Chlamydomonas reinhardtii

Heliyon. 2022 Jan 21;8(1):e08811. doi: 10.1016/j.heliyon.2022.e08811. eCollection 2022 Jan.

Authors

Soufiane Fal^{1

2}, Abderahim Aasfar¹, Reda Rabie^{1

3}, Abelaziz Smouni², Hicham El Arroussi^{1

4}

Affiliations

¹ Green Biotechnology Laboratory, Moroccan Foundation for Advanced Science, Innovation and Research (MASCIR), Rabat Design Center, Rue Mohamed Al Jazouli - Madinat Al Irfane, Rabat, Morocco.
² Plant Physiology and Biotechnology Team, Center of Plant and Microbial Biotechnology, Biodiversity and Environment, Faculty of Sciences, Mohammed V University in Rabat, Morocco.
³ University Sidi Mohamed Ben Abdellah, Faculty of Sciences and Techniques of Fez, Laboratory of Applied Organic Chemistry, Fez, Morocco.
⁴ Agrobiosciences Program, University Mohamed 6 Polytechnic (UM6P), Ben-Guerir, Morocco.

Abstract

Salinity is one of the most significant environmental factors limiting microalgal biomass productivity. In the present study, the model microalga Chlamydomonas reinhardtii (C. reinhardtii) was exposed to 200 mM NaCl for eight days to explore the physiological, biochemical and metabolomic changes. C. reinhradtii exhibited a significant decrease in growth rate, and Chl a and Chl b levels. 200 mM NaCl induced ROS generation in C. reinhardtii with increase in H₂O₂ content. This caused lipid peroxidation with increase in MDA levels. C. reinhardtii also exhibited an increase in carbohydrate and lipid accumulation under 200 mM NaCl conditions as storage molecules in cells to maintain microalgal survival. In addition, NaCl stress increased the content of carotenoids, polyphenols and osmoprotectant molecules such as proline. SOD and APX activities decreased, while ROS-scavenger enzymes (POD and CAT) decreased. Metabolomic response showed an accumulation of the major molecules implicated in membrane remodelling and stress resistance such oleic acid (40.29%), linolenic acid (19.29%), alkanes, alkenes and phytosterols. The present study indicates the physiological, biochemical and metabolomic responses of C. reinhardtii to salt stress.

Keywords: Biochemical response; C. reinhardtii; Metabolomic analysis; Physiological alteration; ROS; Salt stress.