ISOLATES OF MELOIDOGYNE-HAPLA WITH DISTINCT MITOCHONDRIAL GENOMES

Because two conflicting reports of the structure of the Meloidogyne ha pla mitochondrial genome exist, we compared the mitochondrial DNA (mtD NA) purified from two isolates of M. hapla: one from San Bernardino Co unty in southern California (BRDO) and the other from England. The aut henticity of the BRDO isolate in particular was confirmed by examinati on of morphological characters, isoenzyme analysis, and differential h ost range tests. Restriction analysis revealed that mtDNA from the BRD O and English isolates corresponded to only the structure first report ed, although significant differences between the two isolates were app arent. Southern blots probed with cloned, cytochrome oxidase I (cox-1) DNA from Romanomermis culicivorax mtDNA confirmed that the analyzed D NA was of mitochondrial origin. Thus, M. hapla has at least two distin ct but presumably related mitchondrial genomes, plus at least one very different structure. These data are discussed with reference to recen t molecular diagnostic and phylogenetic analyses of Meloidogyne.