An ndh9 mitochondrially based phylogeny of the Oomycota
The Phylum Oomycota, a group of "lower" or microfungi, have recently been placed in the newly erected Kingdom Straminopila. In this study, a mitochondrial gene has been used to infer a molecular phylogeny for representative genera of three major orders of oomycetes. The locus used (ndh9, nuo3, nad.9, or ND9) encodes subunit 9 of NADH:ubiquinone oxidoreductase (Complex I) of the respiratory electron transport chain Although normally nuclear-encoded in eukaryotes, ndh9 i mitochondrially encoded in plants and some lower eukaryotes, notably the Oomycota. The data set in this work consists of 401 nd.h.9 nucleotides generated by PCR from nine oomycete genera. Nucleotide data from the chlorophyte Prototheca wickerhamii were used as the outgroup in the analyses. Distance and character-state analysis by neighbor-joining (NJ), maximum parsimony (MP), and maximum likelihood (ML) analyses were used to infer an oomycete molecular phylogen^. The resulting phylogeny using ndh.9 is shown to be consistent with a previously generated cox2 phylogeny, and with a variety of both morphological and biochemical characters. The sole discrepancy with the cox2 phylogeny resides in the placement of Leptomitus of the Leptomitales.