**Abstract**

When a *Dunaliella salina* cell is stressed, a series of adaptive changes occur, including gene expression regulation, acclimating to new conditions, and maintaining survival. Due to the natural habitat and the high adaptability of this extraordinary organism to the intolerable environment for other photosynthetic organisms, the plasticity of metabolic pathways has been proven. In this regard, it seems that manipulating the amount and activity of enzymes involved in these pathways is inevitable. Therefore, both nuclear and organelles genomes must sense environmental fluctuation quickly and accurately to respond appropriately to those changes during transcription or post-transcriptional stages. In addition to the nuclear genome, *D. salina* has an autonomous chloroplast genome, consisting of 66, and a mitochondria genome consisting of seven genes encoding proteins. The mystery of *D. salina* survival in harsh environments, from 5 M salinity salt lakes to the Atacama Desert Caves, lies in this flexibility and adaptability from molecular levels to the metabolic pathway of *D. salina* cells. Therefore, who can say prudently that the prosperity of *D. salina* depends on flexibility in the regulation of plastid gene expression?

**Keywords:** acclimation, transcription, *Dunaliella salina*, chloroplast genome, survival
