Molecular phylogeny of an unidentified Haliphthoros-like marine oomycete and Haliphthoros milfordensis inferred from nuclear-encoded small- and large-subunit rRNA genes and mitochondrial-encoded cox2 gene

Abstract

The SSU rRNA, LSU rRNA, and cox2 genes of an unidentified Haliphthoros-like marine oomycete (NJM0034) and Haliphthoros milfordensis (NJM0131) were sequenced, and their phylogenetic relationships are analyzed and discussed. All phylogenetic trees showed that NJM0034 and NJM0131 were branched before separation of the two main saprolegnian and peronosporalean clades. These data suggest that the clear phylogenetic separation of those marine oomycete endoparasites from the two main oomycete clades. Excepting the LSU rRNA gene tree, NJM0034 and Haliphthoros spp. did not form a monophyletic group. On the other hand, H. milfordensis NJM0131 clustered with H. philippinensis SANK 15178, not with H. milfordensis NJM9434 in the cox2 amino acid sequence (COII) tree. This result strongly suggests that a taxonomic reinvestigation of the genus Haliphthoros should be considered.