Molecular phylogeny of three hitherto unreported Alexandrium species: Alexandrium hiranoi, Alexandrium leei and Alexandrium satoanum (Gonyaulacales, Dinophyceae) inferred from the 18S and 26S rDNA sequence data

Abstract

K.-Y. Kim, M. Yoshida and C.-H. Kim. 2005. Molecular phylogeny of three hitherto unreported Alexandrium species: Alexandrium hiranoi, Alexandrium leei and Alexandrium satoanum (Gonyaulacales, Dinophyceae) inferred from the 18S and 26S rDNA sequence data. Phycologia 44: 361–368.Nuclear-encoded 18S and partial 26S ribosomal DNA (rDNA) sequences of Alexandrium hiranoi, A. leei and A. satoanum were analyzed for the first time. The sequences of the 26S rDNA D1–D3 region of A. affine, A. catenella, A. fraterculus and A. tamarense were also determined. The maximum-likelihood and maximum-parsimony phylogenies on the basis of the 18S and 26S rDNA sequence data showed that the monophyletic Alexandrium was subdivided into three main groups of which genetic delineation was congruent to the shape of the posterior sulcal plate. Alexandrium hiranoi was genetically closely related to A. pseudogonyaulax and A. taylorii. Alexandrium leei formed the deepest branch without apparent genetic affiliation to the other Alexandrium species. Alexandrium satoanum consistently formed a sister group with A. hiranoi, A. pseudogonyaulax and A. taylorii, but was separated from them with high bootstrap supports. A Blast search of GenBank showed that A. affine, A. catenella, A. fraterculus and A. tamarense sequence data corresponded to their morphological species designation.