Molecular Identification of a New Dunaliella salina Strain, and its Carotenogenesis in Response to Nitrate

A new strain of Dunaliella from Maharlu salt lake, southeast of Shiraz, Iran, was isolated and morphologically identified as Dunaliella salina strain, SUDCC M01-91/4. An integrated approach using both molecular and physiological attributes was used to identify the isolated strain as D. salina. A novel primer amplifying conserved region of 18S rDNA is introduced for identifying Dunaliella genus. Constructed dendrogram revealed a phylogenetic relationship between the isolated strains and some other β-carotene hyper-producer species. Changes in physiological parameters such as growth, pigments content and also reactive oxygen species (ROS) production in terms of lipid peroxidation, by isolated strain in response to different concentrations of potassium nitrate in culture media, were studied. The increase in β-carotene production in the present study under nitrate deficiency could be due to increase in ROS production as revealed in high lipid peroxidation. Physiological responses of the isolated strain to nitrate deficiency support the morphological and molecular identification of the strain as carotenogenic D. salina.