一株杜氏藻的分子鉴定与耐盐特性

杜氏藻属（Dunaliella）是绿藻门的一类极端耐盐的单细胞藻。本文通过核基因ITS序列和叶绿体基因rbcL序列确定了一株分离自舟山群岛的杜氏藻D3的分类地位，并比较了4种NaCl浓度对该藻的生长、蛋白质含量、总脂含量和叶绿素荧光参数的影响，以期为该藻在今后的科研与应用提供基础资料。结果表明，该藻与23株杜氏藻的ITS序列之间的遗传距离在0．026—0．136之间，与21株同属藻rbcL序列之间的遗传距离在0．005～0．060之间，由遗传距离和聚类图推断该杜氏藻D3属于D．viridis。不同NaCl浓度对该藻D3生长影响表明1．00mol·L^-1NaCl培养藻生长最快，培养至10d时，0．44mol·L^-1、2．00mol·L^-1和3．00mol·L^-1NaCl培养藻细胞数分别是它的85．9％、93．2％和80．7％；该藻可溶性蛋白含量在1．00mol·L^-1 NaCl培养最高；藻细胞总脂含量在0．44-2．00mol·L^-1NaCl浓度范围内随盐度升高总脂含量增加，2．00mol·L^-1 NaCl培养最高（占干重的22．3％）；叶绿素荧光参数（F√Fm、ФPSII qp）在高盐（3．00mol-LL^-1 NaCl）培养显著降低，而NPQ则升高。

Molecular Identification and Halophilic Charactristics of a Strain of DunalieUa D3

The genus Dunaliella is a kind of halophilic unicellular algae of Chlorophyta. In this paper, a strain ofDunaliella D3, isolated from Zhoushan islands of Zhejiang Province, was determined its taxonomy based on the nucleotide sequence of ITS and the chloroplast gene of rbcL. Then, the effects of four kinds of NaCl concentrations on the growth, protein content, total lipid content and chlorophyll fluorescence parameters of the Dunaliella were compared, which would provide a foundation for scientific research and application in the future. The distances ranged from 0.026 to 0.136 based on the ITS sequence olD3 and the other 23 strains of Dunaliella, and the distances varied from 0.005 to 0.060 based on the rbcL sequence of D3 and the other 21 strains of Dunaliella. The genetic distances and phylogenetic tree confirmed D3 as D. viridis. The effect of different NaCl concentration on the growth of D3 showed that the algae grew fastest in 1.00 mol·L^-1 NaCl medium, and the cell density of 0.44 mol·L^-1, 2.00 mol.L1 and 3.00 mol·L^-1 NaCl culture was 85.9%, 93.2% and 80.7% of that of 1.00 mol·L^-1 NaCl on the 10th day, respectively. The soluble protein content was the highest in the 1.00 mol·L^-1 NaCl medium. The total lipid content of D. viridis D3 was highest in 2.00 mol·L^-1 NaCl medium, which accounted for 22.3% of the dry weight. The chlorophyll fluorescence parameters of PSII （Ff Fro）, actual photochemical efficiency of PSII ФPSII ）, photochemical fluorescence quenching （qp） deceased, but non photochemical fluorescence quenching （NPQ） increased in 3.00 mol·L^-1 NaCl culture.