Morphological and molecular characterisation of Meloidogyne populations associated with Andean fruits and Musa plants

Twenty four Meloidogyne populations from Andean fruits (Cyphomandra betacea, Solanum quitoense, Passiflore ligularis) and Musa plants occurring in Colombia were identified using different approaches: morphological and morphometrical analyses by light (LM) and scanning electron microscopy (SEM), species-specific primers, protein analyses, molecular analyses of sequences and phylogenetic analyses. Morphometric and/or morphological features allowed separation of populations into species groups as a first step towards identification. Although purification of populations is recommended as a second step in the identification, only three species could be successfully purified. However, to overcome the mixed species problem for all other species, Meloidogyne identification was based on a single young egg-laying female (protein analysis) and DNA (for species-specific PCR and sequence analyses) was always extracted from a single juvenile. Six known species were identified: M. incognita, M. javanica, M. arenaria, M. hapla, M. konaensis and M. paranaensis. The last two species had never been recorded previously in Colombia but since they show morphological features of M. incognita and M. arenaria they were probably misidentified in the past. Isozyme analysis also recovered two phenotypes that could not be connected to known Meloidogyne species. The first phenotype represents a new species that is currently under investigations of researchers from Holland and Brazil and, additional specimens of the second phenotype are needed for accurate morphological and morphometrical studies.