- International Journal of Systematic and Evolutionary Microbiology
- Volume 43, Issue 2
f DNA Relatedness between Xenorhabdus spp. (Enterobacteriaceae), Symbiotic Bacteria of Entomopathogenic Nematodes, and a Proposal To Transfer Xenorhabdus luminescens to a New Genus, Photorhabdus gen. nov.
- Authors: N. E. Boemare*, R. J. Akhurst, R. G. Mourant
- *Corresponding author.
- First Published Online: 01 April 1993, International Journal of Systematic and Evolutionary Microbiology 43: 249-255, doi: 10.1099/00207713-43-2-249
- Subject: Original Papers Relating To Systematic Bacteriology
- Issue Published:
DNA Relatedness between Xenorhabdus spp. (Enterobacteriaceae), Symbiotic Bacteria of Entomopathogenic Nematodes, and a Proposal To Transfer Xenorhabdus luminescens to a New Genus, Photorhabdus gen. nov., Page 1 of 1< Previous page | Next page > /docserver/preview/fulltext/ijsem/43/2/ijs-43-2-249-1.gif
The levels of DNA relatedness for a broad sample of Xenorhabdus strains isolated from different species of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) and from different geographical sources were estimated by the hydroxyapatite method. The level of DNA-DNA relatedness for the two phases of each isolate tested was not significantly different from 100%, demonstrating unequivocally that the phase variation demonstrated by all Xenorhabdus spp. is not due to contamination. The isolates of the described Xenorhabdus species coalesced into different DNA relatedness groups, confirming that Xenorhabdus nematophilus, Xenorhabdus bovienii, Xenorhabdus poinarii, and Xenorhabdus beddingii, defined on the basis of phenotypic differences, are valid species. The symbiont of Steinernema intermedia also coalesced with the X. bovienii isolates. This was the only symbiont of seven recently described and unamed Steinernema spp. (including Steinernema ritteri, Steinernema rara, and Steinernema anomali) that formed a group with any of the previously described Xenorhabdus species; new species descriptions are required to accommodate the other taxa, but too few isolates were available to allow satisfactory descriptions of them. The DNA relatedness data also showed that the bacteria currently classified as Xenorhabdus luminescens are significantly different from all other Xenorhabdus strains. These data strongly support indications from previous studies of phenotypic characteristics, cellular fatty acids, and DNA relatedness that X. luminescens should be classified as a separate genus. A new genus, Photorhabdus, with an amended description of the type species, Photorhabdus luminescens, is proposed.
Copyright © 1993 International Union of Microbiological Societies | Published by the Microbiology Society
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