Isolates of Meloidogyne hapla with Distinct Mitochondrial Genomes


  • J. J. Peloquin
  • D. McK. Bird
  • I. Kaloshian
  • W. C. Matthews


Because two conflicting reports of the structure of the Meloidogyne hapla mitochondrial genome exist, we compared the mitochondrial DNA (mtDNA) purified from two isolates of M. hapla: one from San Bernardino County in southern California (BRDO) and the other from England. The authenticity of the BRDO isolate in particular was confirmed by examination of morphological characters, isoenzyme analysis, and differential host range tests. Restriction analysis revealed that mtDNA from the BRDO and English isolates corresponded to only the structure first reported, although significant differences between the two isolates were apparent. Southern blots probed with cloned, cytochrome oxidase I (cox-l) DNA from Romanomermis culicivorax mtDNA confirmed that the analyzed DNA was of mitochondrial origin. Thus, M. hapla has at least two distinct but presumably related mitchondrial genomes, plus at least one very different structure. These data are discussed with reference to recent molecular diagnostic and phylogenetic analyses of Meloidogyne. Key words: DNA, Meloidogyne hapla, mitochondrial DNA, molecular diagnostics, nematode, phylogeny, restriction fragment length polymorphism.