Shiraz University Press Molecular Biology Research Communications 2322-181X 1 1 2012 07 29 Molecular identification of Dunaliella viridis Teod. strain MSV-1 utilizing rDNA ITS sequences and its growth responses to salinity and copper toxicity 8 15 205 10.22099/mbrc.2012.205 EN Mansour Kharati-Koupaei Department of Biology, Collage of Sciences, Shiraz University, Shiraz, Iran Hajar Zamani Department of Biology, Collage of Sciences, Shiraz University, Shiraz ,Iran Ali Moradshahi Department of Biology, Collage of Sciences, Shiraz University, Shiraz,Iran Journal Article 2012 06 06 In addition to biochemical, physiological and morphological analysis, molecular studies provide additional information for establishing phylogenetic relationships among different species and strains of the genus <em>Dunaliella</em>. In the present study, based on neighbor- joining analysis of the nuclear rDNA ITS sequence, a novel strain of the green algae <em>Dunaliella viridis</em> was identified from Maharlu salt lake in Shiraz, Iran. The phylogenetic tree shows that the new strain is part of a clade containing several strains of <em>D. viridis</em>. The new strain was designated <em>Dunaliella viridis </em>MSV-1 and submitted to the GenBank under the accession number HQ864830.  The optimum salinity for MSV-1 growth is between 1.0 to 1.5 M NaCl and does not turn red up to 4.5 M NaCl, confirming identity of the isolated strain. With respect to growth response to copper toxicity, increase in Cu²⁺ concentration from 1 to 30 µM, caused progressive increase in cell number ml^-1 of culture over time, whereas reduction in cell number occurred at 100 and 200 µM Cu⁺². Nano copper (colloidal copper with 40 nm dimensions) showed less toxicity compared to the ionic form. Cell number ml^-1 of culture did not change up to 200 µM nano copper but decreased at 500 µM. In conclusion, the analysis of the ITS sequence is a reliable basis for establishing evolutionary relationships among species and strains of the genus <em>Dunaliella</em> and due to rapid growth at 1.5 M NaCl and high cell density, <em>D. viridis</em> MSV-1 is a good candidate for biofuel production from microalgae. https://mbrc.shirazu.ac.ir/article_205_f3787dd39844276e4ece8f741aac618a.pdf