4株沙漠土壤衣藻的分离培养及形态和分子鉴定

Study on Morphology and Molecular Phylogeny of Four Desert Chlamydomonas

从古尔班通古特沙漠和塔克拉玛干沙漠采集沙样,先进行混合培养,混培藻液采用96孔板有限稀释法和平板法,分离到4株微藻(GTD2A,GTD4C,TLD7A-2,3a-5),采用传统形态鉴定方法及18SrDNA片段克隆分别对筛选的4株微藻进行鉴定,并进行系统发育分析。结果表明:通过形态学特征将4株藻初步鉴定为绿藻门、绿藻纲、团藻目、衣藻科。采用分子生物学方法克隆的18SrDNA片段进行复核的结果表明GTD2A2与GenBank数据库中的Chlamydomonas debaryana(FR865608.1)同源性达到了99.92%,说明已经鉴定至种。GTD3a-5、GTD4C、TLD7a-2与GenBank数据库中Chlamydomonas baca(FR865613.1)、C.reinhardtii和Chlamydomonas sp.(FR865563.1)3个藻种的同源性分别达到了98.10%、98.69%和97.65%。研究确定了4株沙漠衣藻的分类地位及其同其它衣藻种的亲源关系,为以后的研究沙漠藻的分子生物学和生理学研究奠定了基础。

To study microalgae species of Gurbantunggut Desert and Takilimakan Desert, this experiment isolated four desert microatgae from the sand samples by using the method of 96-well plate limited dilution and spread plate method,and studied the morphology and phylogeny in a polyphasic approach. Morphologically,the investigated strains could be discriminated in Chlorophyta,Volvocales,Chlamydomonadaceae. The morphological differences were reflected in the four distinct species. The GTD2A2 strain had very high similarity of 99.92% to Chlamydomonas debaryana （FR865608. 1）, which demonstrated that GTD2A2 strains were identified to species. The 18S rDNA gene sequences of GTD3a-5,GTD4C, and TLD7a-2 strain were 98. 10%, 98. 69% and 97. 65% similar to Chlamydomonas baca （FR865613. 1）, C, reinhardtii （M32703. 1）and Chlamydomonas sp. （FR865563.1） ,which demonstrated that GTD3a-5,GTD4C, GTD7A-2 strains were identified to genus. This study clearly defines the taxonomic status of 4 strains of desert Chlamydomonas and Chlamydomonas with other relatives,providing a valuable foundation for further study of desert algae in the molecular biology and physiology.