Received 7 August 1995. Accepted 22 January 1996.
ANALYSIS OF ALEXANDRIUM (DINOPHYCEAE) SPECIES USING SEQUENCES OF THE 5.8S RIBOSOMAL DNA AND INTERNAL TRANSCRIBED SPACER REGIONS1
Article first published online: 28 JUN 2008
Journal of Phycology
Volume 32, Issue 3, pages 424–432, June 1996
How to Cite
Adachi, M., Sake, Y. and Ishida, Y. (1996), ANALYSIS OF ALEXANDRIUM (DINOPHYCEAE) SPECIES USING SEQUENCES OF THE 5.8S RIBOSOMAL DNA AND INTERNAL TRANSCRIBED SPACER REGIONS. Journal of Phycology, 32: 424–432. doi: 10.1111/j.0022-3646.1996.00424.x
This work was supported in part by a Grant-in-Aid for Scientific Research (Nos. 3704 and 03660192) from the Ministry of Education, Science and Culture of Japan and by a grant from the Ministry of Agriculture, Fisheries and Forestry of Japan. We thank Drs. M. Kodama, T. Ogata, Y. Oshima, S. Yoshimatsu, M. Yamaguchi, M. Ishida, and D. M. Anderson for providing cultures of Alexandrium. We also thank Dr. T. Miyata, Mr. N. Nikoh, and the National Institute of Genetics, who helped with our DNA sequence analysis and making phylogenetic trees.
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Alexandrium affine;
- Alexandrium catenella;
- Alexandrium fundyense;
- Alexandrium insuetum;
- Alexandrium pseudogonyaulax;
- Alexandrium tamarense;
- DNA sequencing;
- internal transcribed spacer;
- molecular identification;
- ribosomal DNA;
- toxic dinoflagellates
The 5.8S ribosomal RNA gene (rDNA) and flanking internal transcribed spacers 1 and 2 (ITS1 and ITS2) from 7 isolates of Alexandrium catenella (Wedon et Kofoid) Taylor, 13 isolates of A. tamarense (Lebour) Balech, 2 isolates of A. affine (Fukuyo et Inoue) Balech, and single isolates of A. fundyense Balech, A. insuetum Balech, and A. pseudogonyaulax (Biecheler) Horiguchi ex Yuki et Fukuyo comb. nov. from Japan, Thailand, and the United States were amplified using the polymerase chain reaction (PCR), sequenced, and subjected to phylogenetic analysis. The sequences ranged from 518 to 535 base pairs (bp) exclusive of the 18S and 28S rDNA coding regions. Sequence comparisons revealed seven divergent “ITS types” designated as follows: 1) catenella type, 2) tamarense type, 3) WKS-1 type, 4) Thai type, 5) affine type, 6) insuetum type, and 7) pseudogonyaulax type. Isolates of the tamarense type from various locations in Japan and the United States and of A. fundyense from the United States were closely related to each other and were clearly divergent from isolates of A. tamarense WKS-1 (WKS-I type) or A. tamarense CU-15 (Thai type). These latter two strains carried unique ITS types, although they were not distinguishable from isolates of the tamarense type by morphological criteria. Distance values between isolates of the tamarense type and the WKS-1 or Thai type were quite high (about 0.21 and 0.39, respectively). Seven isolates of A. catenella from Japan (catenella type) clearly diverged from the other ITS types already mentioned. Distance values between isolates of the catenella type were extremely low (<0.01), whereas distance values of ITS between the catenella type and the tamarense, WKS-1, or Thai type were 0.17, 0.18, and 0.40, respectively. Isolates of A. affine, A. insuetum, and A. pseudogonyaulax all carried unique ITS types. The ITSs of the tamarense type exhibited two distinct ITS sets, the “A gene” and the “B gene.” The two sequences occurred in a 1:1 ratio in PCR products. In contrast, the ITSs of all other isolates appeared homogeneous. Sequence comparisons also showed that the variations in the 3′ end of ITS1 (150-177 bp) were low within each ITS type but extremely high between ITS types. The number of different nucleotides among the seven Alexandrium types in this 28-bp region is more than 10. High diversity of this region may facilitate the design of DNA probes specific for each ITS type/species of Alexandrium.