PHYLOGENETIC ANALYSIS OF NEMATODES OF THE GENUS PRATYLENCHUS USING NUCLEAR 26S RDNA

We used nucleotide sequences of the large subunit ribosomal genes (265 rDNA) to examine evolutionary relationships among species of the genu s Pratylenchus (Order: Tylenchida, Family: Pratylenchidae), commonly k nown as root-lesion nematodes, Ten species of Pratylenchus were studie d including, P. penetrans, P. crenatus, P. minyus, P. vulnus, P. thorn ei, P. musicola, P. coffeae, P. hexincisus, P. scribneri, and P. brach yurus. The species Hirschmanniella belli, Meloidogyne javanica, Hetero rhabditis bacteriophora, Nacobbus aberrans, Radopholus similis, and Xi phinema index were used as outgroups. Based on parsimony analyses of a pproximately 307 aligned nucleotides of the D3 expansion region of the 26S rDNA, it is clear that species of Pratylenchus are a paraphyletic assemblage. The outgroup taxon H. belli shares a common ancestor with the clade that includes P. vulnus and P. crenatus while N. aberrans a nd R. similis share a common ancestor with 5 other species included in this study. (C) 1997 Academic Press.