两株淡水微囊藻的藻蓝蛋白基因间隔序列(PC-IGS)分析

The analysis of PC-IGS sequences from four freshwater Microcystis sp

对2株编号为003和004的淡水水华微囊藻(Microcystis.sp)的藻蓝蛋白基因间隔序列进行测定,获得长度均为608bp的2条序列.同时从GenBank中获取铜绿微囊藻(Microcystis aeruginosa Kutz,NCBI序列号AJ003179)及惠氏微囊藻(Microcystis wesenbergii,NCBI序列号AF385391)的序列.分别运用MEGA3及ClustalX(Version1.83)软件对这4株藻的PC-IGS序列进行碱基组成分析和序列比对.碱基组成的比对结果表明4株藻的G+C含量分别为003(50.5%),004(51.7%),铜绿微囊藻(50.7%),惠氏微囊藻(52.3%),相差范围在0.2%～1.8%之间,其结果不足以区分这四株微囊藻;序列比对则表明003号藻株与铜绿微囊藻和惠氏微囊藻的序列相似性分别为100%和88.35%,而004号藻株与铜绿微囊藻和惠氏微囊藻的序列相似性比较结果为95.13%和89.04%.此外,文章还探讨了PC-IGS序列作为微囊藻种间鉴定分子标记的可行性.

Two individual PC-IGS ( Phycocyanin Intergenic Spacer ) sequences are determined for the freshwater Microcystis sp. which are numbered 003 and 004 respectively in this study, and two 608bp fragments are acquired. PC-IGS sequences of Microcystis aeruginosa Kütz (NCBI Accession No: AJ003179) and M. wesenbergii (NCBI Accession No: AF385391) are downloaded from the GenBank. Softwares MEGA3 and ClustalX (Version 1.83) are used to analyze these four PC-IGS sequences. The base composition of these four strains are 50.5% for 003, 51.7% for 004, 50.7% for M. aeruginosa Kütz and 52.3% for M. wesenbergii, respectively. The difference of base composition of these four strains ranges from 0.2% ~ 1.8%, which suggests the comparison of base composition is not accurate enough to distinguish the relationship among them. And the result of sequence alignment shows the sequence identity between strain 003 and M. aerginosa Kütz, M. wesenbergii is 100% and 88.35% respectively. And the sequence identity between strain 004 and M. aerginosa Kütz, M. wesenbergii is 95.13% and 89.04% respectively. The possibility of using the PC-IGS sequence as the molecular identifier in the classification of the Microcystis. sp is also discussed.