Identification of mariner-like elements from the root-knot nematode Meloidogyne spp.

The Meloidogyne species are agriculturally important, pests widespread in t he world. These polyphagous endoparasitic nematodes possess an astonishing ability to bypass the plant resistance genes in few generations. However, t he genes and mechanisms involved in this molecular determinism are nor, yet known. Except cytogenetic and cytotaxonomic studies, few data are availabl e concerning their genome. There is therefore an important need of molecula r tools for genetic investigation of their virulence character and other as pects of host-pathogen interactions. In that respect, the presence of,marin er-like-elements (MLEs) was assessed in these endoparasitic nematodes by a polymerase chain reaction (PCR) assay using degenerate primers designed fro m two conserved regions of the mariner transposase open reading frame (ORF) . Four Meloidogyne species of the five tested revealed the presence of MLEs in their genome. Southers blot analysis indicated that sequences hybridizi ng to the mariner transposase-like PCR clones occur at a moderate to low co py number in the different Meloidogyne spp. genomes. The phylogenetic analy sis show that the Meloidogyne MLEs may form new subfamilies of mariner. Mor eover, five PCR clones were shown to possess a continuous ORF suggesting th e presence of putative transposase-like coding regions. (C) 2000 Elsevier S cience B.V. All rights reserved.