Morphological and molecular identification of a strain of the unicellular green alga Dunaliella sp. isolated from Tarquinia Salterns

Abstract

1 - Algae of the genus Dunaliella are among the most studied micro-algae. They are used for the production of feed, for nutritional reinforcement as a vitamin A precursor and for pharmaceuticals and fine chemicals. 2 - The current taxonomy of the genus is based on morphological and physiological attributes including the ability of some species to grow over wide salinity ranges and at extreme salinities, as well as the accumulation of high levels of â-carotene. The taxonomic status of the genus Dunaliella involves some uncertainty, moreover it is very difficult to compare results from different authors, owing to uncertainty on names and species. 3 - In this work, we compare morphological and molecular analysis to characterize a strain of Dunaliella isolated from Tarquinia salt ponds. Samples of natural populations of the unicellular green alga, were collected at various times during the study period to detail the vegetative motile cells and the different stages of its life cycle microscopically. The ITS1 and ITS2 regions were used for the molecular identification analysis. Conserved oligonucleotides of 18S rDNAs (MA3) and speciesspecific primers (DSs), designed from variable sequences, were used to corroborate the identification. 4 - Blast results indicated that our sequences matched at the 100% level with Dunaliella salina Teod reported in Gen Bank. Consequently, based on comparative cell morphology and molecular analysis, the new Dunaliella isolate from Tarquinia salt ponds was classified as D. salina.