Abstract:

Microalgae, as one of the ancestors of photosynthetic microorganisms on earth, are widely exploited for its short growth cycle, fast growth rate and potential to produce high value-added products. However, their scale-up cultivations have been substantially hindered by those adverse effects resulting from various abiotic stresses including high salinity during industrial production processes. Therefore, it is extremely essential to understand the molecular mechanism of salt stress responses in microalgae, which may contribute to the build-up of genetically engineered microalgae or even higher plants. In this mini review, we summarized various proteins involved in the response of eukaryotic microalgae and prokaryotic cyanobacteria to salt stress and their specific mechanisms including transporters maintaining ion homeostasis, accumulating osmotic regulators, antioxidant defense mechanisms, signal proteins and lipid remodeling. Meanwhile, we outlined the recent research progress of halotolerant microalgae including Dunaliella salina, Aphanothece halophytica, Picochlorum sp. and Chlamydomonas W80, and their salt-tolerant genes that are mostly under active investigations. Finally, we briefly discussed the value and application prospect of typical important salt-responsive genes in the breeding of algal species.

Key words: eukaryotic microalgae, prokaryotic cyanobacteria, salt stress, halotolerant algae, molecular mechanisms of responses to salt stress