七株微囊藻系统进化关系的RAPD-PCR分析

应用RAPD-PCR的方法,选用24个随机引物,分析来自不同地区的7株微囊藻的基因组多态性。结果显示,Microcystis.viridis及M.wesenbergii明显与M.aeruginosa区分开。M.aeruginosa分为两个可视为不同种的异源分类单位。作为对照的Anabaena sp.7120与其他微囊藻株表现出完全不同的基因型及更远的遗传距离。 此项研究表明,以基因型而不是表现型为基础,分析蓝藻种内及种间区别是可能的。因此,为解决蓝藻分类问题,特别是在种和属的水平上,提供了重要的线索。结合正在进行的用特异性及准确性强的引物区分微囊藻产毒及非产毒株的方法,RAPD-PCR可望将微囊藻产毒及非产毒株进化关系澄清。

PHYLOGENETIC RELATIONSHIP AMONG SEVEN STRAINS OF MICROCYSTIS BASED ON THE RANDOMLY AMPLIFIED POLYMORPHIC DNA PCR

As a part of the molecular taxonomic revision of the genus Microcystis (Cyanophyceae) , genome DNA divergence within and between three Microcystis species including seven strains from different areas were analyzed electrophoretically after using randomly amplified polymorphic DNA PCR with 24 primers. The main result was summarized as follows: (1)the genus Microcystis includes at least four taxonomic entities which differ in morphology and genetics: M. aeruginosa 101, M. aeruginosa 7820, M. aeruginosa 90 and M sp. ( Dianshan) ; M. viridis ; M. wesenbergii; M. aeruginosa. 41. (2) M. aeruginosa comprises two heterogeneous taxonomic entities which could be viewed as separete species. (3) for their unique genotype and minor morphological variation, M. viridis and M. wesenbergii are regarded as well-established species. (4)as anticipated, Anabaena sp 7120 as the control exhibits entirely different genotype and farther genetic distance than those of other Microcystis strains.The RAPD study on the genus Microcystis illustrates that it is possible to analyze intra- and inter-specific variation of Cyanophytes on the basis of genotype rather than phenotype and , therefore , offers significant and indispensable clues in solving taxonomic problems of cyanophytes, especially at the species and genus levels. Combined with the on-going research on special primers which sensitively and reliably distinguish the toxic and non- toxic strains of Microcystis, RAPD would be a helpful method to understand more explicitly the phylogenetic relationships between toxic and non-toxic strains of the genus Microcystis.