gvpA-C间隔区在微囊藻株系分型中的应用

APPLICATION OF THE GVPA-C INTERGENIC SEQUENCE IN TYPING OF MICROCYSTIS

从暴发水华的水体分离微囊藻(Microcystis)株,并依据gvpA-C间隔区和16S rDNA序列对其分型和比较。在gvpA-C间隔区序列中,有的类型具有一段172—176 bp的额外序列。以不包括额外序列的0.27 kb序列相比较,不同类型之间差异碱基位点达50余个。在16S rDNA碱基变异集中的0.69 kb序列中,不同类型之间有差异的碱基位点共有8个。与16S rDNA序列相比,微囊藻gvpA-C间隔区序列具有高度变异性,并且其PCR扩增可一步完成,不受其他细菌污染,因而可用于微囊藻株系分型。由于横向转移,2种分型存在交叉关系。此外,原本含有或不含有额外序列的微囊藻gvpA-C间隔区序列在系统进化树中分别聚成一簇。

Microcystis strains isolated from bloom-forming ponds were analyzed based on gvpA-C intergenic sequence and 16S rDNA.Several gvpA-C intergenic sequences shared an 172—176 bp extra sequence.An alignment of different types of 0.27 kb sequences,exclusive of the extra sequence,showed over 50 substitutions,whereas in a 0.69 kb hot spot region of 16S rDNA only 8 substitutions were identified.Compared to 16S rDNA,the gvpA-C intergenic sequence was generated by one-step PCR without contamination from co-existing bacteria and showed much higher variability,therefore should be useful in typing of Microcystis.Due to horizontal gene transfer,the two sets of types demonstrated an intersecting relationship.In addition,Microcystis gvpA-C intergenic sequences with or without the extra sequence formed two distinct clusters in a phylogenetic tree.