Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 6/25/2000
Publication Date: N/A
Technical Abstract: The criteria (e.g., morphology, life cycle, and host range) currently used to describe species and isolates of Pasteuria have proved unsufficient for taxonomic purposes. To assess how recent advances in the molecular biology of Pasteuria could assist in resolving the phylogenetic relationships among Pasteuria spp., the 1,485-bp sequence of the 16S rDNA from an Illinois Pasteuria isolate that parasitizes Heterodera glycines was compared to homologous sequences of 32 other bacterial species, including P. ramosa and P. penetrans, parasitic to water fleas and root-knot nematodes, respectively. Phylogenetic analyses confirmed the position of the genus Pasteuria among the Bacillaceae, and further revealed that P. ramosa diverged before the speciation of nematode-infecting Pasteuria, with a dissimilarity index of 7% compared to 2% between P. penetrans and the Illinois Pasteuria. The three Pasteuria differed in the folding patterns of their 16S rRNA molecules, with the definitive difference occurring in the hypervariable region of helix 6.