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 unidentifi ed 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.

The Evolutionary Phylogeny of Oomycetes—Insights Gained from Studies of Holocarpic Parasites of Algae and Invertebrates

“…Haliphthoros also requires splitting into more taxa, because the sequenced isolates fell into two well-separated clades ( Fig. 1.2b), which were not coincidental with the two currently recognized taxa Haliphthoros milfordensis and Haliphthoros phillipensis (Sekimoto et al, 2007). Because of their very different host ranges and morphological differences, we suggest that the Olpidiopsidales and Haliphthorales probably merit being retained in separate orders, but more sequence data are required before these can be unequivocally defined.…”

“…A range of marine parasites of seaweeds and invertebrates was selected for an integrated study into their molecular phylogeny, morphological development, and ultrastructural characteristics (Sekimoto, 2008;Sekimoto et al, 2007Sekimoto et al, , 2008a. Phylogenetic trees based on the SSU rDNA ( Fig.…”

Molecular phylogeny of terrestrial holocarpic endoparasitic peronosporomycetes, Haptoglossa spp., inferred from 18S rDNA

“…The existence of the former two subclasses in the Peronosporomycetes has been supported by phylogenetic analysis on DNA sequence data including 18S rDNA (Dick et al 1999), 28S rDNA (Riethmuller et al 1999), and the mitochondrial cytochrome c oxidase subunit 2 (cox2) locus (Hudspeth et al 2000;Cook et al 2001). Recent molecular phylogenetic studies revealed that some marine holocarpic peronosporomycetes that are endoparasitic in the Crustacea or algae were not included in any clade of two subclasses and formed a separate clade at the basal position of the Peronosporomycetes (Cook et al 2001;Kupper et al 2006;Sekimoto et al 2007). Holocarpic endoparasitic peronosporomycetes have been discovered in both the marine and the terrestrial environment (Karling 1981).…”

Development and preliminary evaluation of a real-time PCR assay for Halioticida noduliformans in abalone tissues

“…Each gene sequence was then aligned using the optimal alignment option of DNAMAN with gene sequences from other closely related Perono sporomycete species sequences available from GenBank, particularly with organisms within the Halioticida/ Haliphthoros/Halocrusticida clade (accession nos. AB178866, AB285218, AB285222-30), in order to iden tify conserved regions for designing speciesspecific primers (Sekimoto et al 2007, Macey et al 2011. Standard criteria were utilized for primer design (Bustin 2000, 2002, Bustin & Nolan 2004.…”

“…The small subunit and large subunit ribosomal DNA (SSU and LSU rDNA, respectively) gene regions as well as the mitochondrial DNA (mtDNA) cytochrome oxidase subunit II (cox2) gene region of H. noduliformans were selected to design speciesspecific PCR primers. An almost complete sequence of each gene was obtained using PCR with amplification primers SR1 and SR12 (Nakayama et al 1996) for the SSU rDNA gene, primers LSU-00021F (Sekimoto et al 2007) and LSU-1170R (Petersen & Rosendahl 2000) for the LSU rDNA gene, and finally primers COX2-For3 and COX2-Rev3 (Sekimoto et al 2007) for amplification of the cox2 gene ( Table 2). The reaction mixtures (25 µl; performed in triplicate) were prepared using 5 to 10 ng genomic DNA, 1 × KAPA Taq ReadyMix (Kapa Biosystems; Catalog #KK1006) and 400 nM of each primer.…”