广东省水库微囊藻的产毒特征和ITS序列的遗传多样性分析

ITS Sequences Analysis and Toxin Characteristic of Microcystis Strains Isolated from Guangdong Reservoirs

摘要:

为了解广东省水库微囊藻的产毒特征和ITS 序列的遗传多样性,从广东省供水水库中分离得到28 株微囊藻(Microcystisspp.),对它们的产毒特征和15 株微囊藻的ITS 序列进行了分析.高效液相色谱(HPLC)和微囊藻毒素合成酶基因mcyE 的检测结果表明,广东省水库中的微囊藻以产毒藻株占优势,微囊藻毒素的主要类型为MC-RR.广东省15 株藻株的ITS 序列相似性大于93.2%,在用相邻法(NJ)构建的系统树上,不同形态的种和不同地理区域的藻株没有区分开,产毒和非产毒藻株没有形成独立分支.这说明微囊藻ITS 序列的遗传多样性较低,ITS 序列和mcyE 存在没有相关性,表型不能够反映藻株的进化关系.因此,有必要将藻类传统分类方法与分子方法结合起来对蓝藻进行重新分类.

Abstract:

In order to understand the toxin characteristics and ITS sequences diversity of Microcystis in Guangdong reservoirs, twenty-eight Microcystis strains were isolated, and their toxin characters and ITS sequences obtained from fifteen Microcystis strains were analyzed. The results showed that microcystin-producing genotypes were dominated in Guangdong reservoirs by HPLC and PCR method of microcystin synthase gene (mcyE), and the main type of microcystin was MC-RR. ITS sequences of Microcystis strains from Guangdong reservoirs had more than 93.2% similarity. Neighbour-joining (NJ) tree indicated that different species and origin from different regions could gather in a group, and toxic and non-toxic strains could not be separated. It was suggested that genetic diversity of Microcystis strains in Guangdong reservoirs was low, and there were no correlation between ITS sequences and the presence of mcyE. Furthermore, phenotypes of Microcystis strains did not necessarily reflect their phylogeny. So the combination of traditional and molecular approaches required to reassess the current cyanobacterial taxonomy should become the focus in the future.