二种淡水微囊藻rDNA16S-235基因间隔区的序列测定与分析

本研究采用PCR及序列测定的方法,对我国淡水铜绿微囊藻有毒株(M8641)和另一低毒的种类惠氏微囊藻(M574)rDNA16S-23S基因间隔区进行了序列的测定和分析,结果表明:rDNA16S-23S基因间隔区可以作为一个精细且稳定的指标,用于微囊藻的分类和鉴定。并从分子水平提出了铜绿微囊藻与惠氏微囊藻在种系发生上有较近缘的关系。本文首次对微囊藻属Microcystis rDNA基因间隔区全序列作了报道,为微囊藻属的鉴定及系统学研究提供了分子基础。  

SEQUENCE ANALYSIS OF rDNA 16S-23S INTERGENIC SPACER FROM MICROCYSTIS AERUGINOSA AND MICROCYSTIS WESENBERGII IN DONGHU LAKE, CHINA

The rDNA 16S-23S intergehic spacer regions from Microcytis aeruginosaand Microcystis wesenbergii in Donghu Lake of China were sequenced and analyzedto illustrate the evolutionary affiliations between toxic and nontoxic strains in genus.The rDNA spacer sequences ranged from 360bp to 364bp exclusive of 16S and 23SrDNA coding regions, containing a Ile tRNA gene. Sequence comparisons bycomputer programs showed that distance values between two species were about 0.05,whereas distance values between two toxic strains of Microcystis aeruginosa (8641 and7820) were 0.04, which indicated Microcystis aeruginosa and Microcystiswesenbergiihas a quite close relationship. In addition, Sequence comparisons showed the variationsin the position 282-295bp were high between tWo species. High diversity of thisregion may facilitate the design of DNA probes specific for toxic Microcystis aeruginosa in Denghu Lake of China. It is the first sequence report of rDNA 16S-23Sintergenic spacer regions for Microrystis, and the sequences will serve as the basis forthe indepth studies on the phylogeny of Microcystis.