16SrRNA基因与16S-23SrRNA转录单元内间隔区序列分析及其在节旋藻和螺旋藻分类鉴定中的应用

Application of the Sequences Analysis of the 16S rRNA Gene and ITS of 16S-23S rRNA to the Systematic Study of the Genus Arthrospira and Spirulina

测定了节旋藻属 3个品系和螺旋藻属 1个品系的全长 1 6SrRNA基因和 1 6S 2 3SrRNA转录单元内间隔区序列 (ITS) ,分析了已知的节旋藻、螺旋藻和相关品系的相应序列的同源性 ,构建了系统发生树 ,并评价了这两段DNA序列在节旋藻、螺旋藻种属分类和种质鉴定中的意义。结果表明 :( 1 ) 1 6SrRNA基因序列和ITS序列均可用于节旋藻属和螺旋藻属的属间分类 ,以两序列为基础的系统学分析结果一致 ;( 2 )ITS序列变异程度高于 1 6SrDNA序列 ,适用于节旋藻和螺旋藻属内品系或种质鉴定 ;( 3)节旋藻属可明确界定 ,1 6SrRNA基因序列相似性大于 98% ,ITS序列相似性大于 88% ;( 4 )螺旋藻属某些品系间 1 6SrDNA序列和ITS序列相似性较低 ,与不同属间的序列相似性程度为同一水平。

It is sequenced and analysed that full length 16S rRNA gene and 16S 23S rRNA internally transcribed spacer (ITS) sequences of 3 strains from genus Arthrospira and 1 strain from genus Spirulina . Sequences of the four strains were compared with those of strains of all known Arthrospira , Spirulina and related cyanobacteria. Molecular phylogenetic dendrograms were constructed based on the genetic distance analysis. The possibility for classification and identification of Arthrospira and Spirulina at genus and species level were evaluated. The results showed that: (1) At the genus level, both the sequence of 16S rRNA gene and that of ITS were suitable for the classification and identification of Arthrospira and Spirulina . And the clustering analysis using the two sequences showed the same results; (2) Due to its high variability, the sequence of ITS is the more appropriate molecular marker for differentiating the strains of same genus than that of 16S rRNA gene; (3) The sequence similarity values of 16S rRNA gene and the ITS between different strains of Arthospira were all larger than 98% and 88% respectively, indicating that these strains belong to the same genus; (4) The sequence similarity values of 16S rRNA gene and the ITS between some strains of Spirulina were quite low and were at the same level as that between different genus.