Tracing of systematic characters of Bangiales (Rhodophyta) based on molecular phylogeny inferred from sequences of nuclear small subunit rRNA genes
2004
Matsuyama Serisawa, K. (Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa) | Yamazaki, S. | Kitade, Y. | Serisawa, Y. | Kuwano, K. | Saga, N.
Abstract: Tracing of 15 systematic characters of Bangiales in which the genus Bangia and Porphyra are included was conducted based on a molecular phylogenetic tree constructed from small subunit (SSU) rRNA gene sequence data of 57 strains using ACCTRAN optimization. The SSU rRNA gene sequence data of Porphyra were determined in seven species including three unregistered species. In the phylogenetic tree, most strains diverged largely into three clades, one Bangia clade and, two Bangia-Porphyra complex clades. This indicates that the genus Bangia and Porphyra are not monophyletic. In tracing, the evolution of gametophyte shape (systematic character of the genus) from cylindrical to leafy or leafy to cylindrical is considered to have occurred at least once or twice, respectively. The evolution of the cell layer in gametophytes (systematic character of the subgenus Diploderma) from monostromatic to distromatic is considered to have occurred once, but monostromatic strains appeared in two lineages. The evolution of chloroplast number per ceil in gametophytes (systematic character of the subgenus Diplastidia) from monoplastid to diplastid is suggested to have occurred twice in different lineages. Although several assemblages were confirmed, strains with the same character status appeared in various lineages in terms of other systematic characters. Therefore, the systematic characters used in the present study were concluded not to reflect the SSU rRNA phylogeny. This is the first report on tracing systematic characters in Bangiales.
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