Phylogenic analysis of Aphanizomenon flos-aquae distributed in Japan on partial sequence of rbcLX

Abstract

To clarify the phylogeny of Aphanizomenon flos-aquae in Japan, genetic analysis was performed of specimens collected from five lakes and one pond in Japan. After the partial region of rbcLX (rivulose - 1,5 - bisphosphate carboxylase gene) was amplified, the sequences were determined and compared among the specimens. A. flos-aquae examined in this study were distinguishable into the three types. Identical sequences were found among specimens from Lake Toro, Lake Suwa and LakeYogo and between Lake Takkobu and the pond of Kyoto University. The sequence of the specimens from Lake Barato was identical to that of the axenic strain isolated from Lake Kasumigaura. A. flos-aquae with an identical sequence were collected from lakes and pond in Japan regardless of geographic location. This indicated that A. flos-aquae categorized into various genotypes are potentially distributed throughout Japan. The specimens with the identical sequence have also exhibited some morphological similarities to each other. Those from Lakes Toro, Suwa and Yogo formed bundle-like aggregations, whereas the others did not. The specimens from Lake Takkobu and the pond of Kyoto University were distinguishable from those from Lake Barato by the extent of the constriction between cells, the formation of akinete, and the shape of heterocysts. Therefore, the classification by rbcLX analysis was supported by some morphological characteristics.