Characterization of the atypical Meloidogyne arenaria (Tylenchina: Meloidogynidae) in Japan

Genus Meloidogyne parasitizes and causes galling on host roots with heavy yield losses. Meloidogyne arenaria (Neal 1889) Chitwood 1949, one of the major species, is found in Japan and can be divided into two genotypes: M. arenaria A2-J and A2-O. Whereas the latter is typical M. arenaria, the former is empirically considered as atypical morphologically and genetically, but its detailed characteristics and phylogenetic relationships have not been described. First, we examined the perineal pattern, isozyme pattern, and PCR products with the C2F3/1108 primer set of M. arenaria A2-J and confirmed that all the populations of M. arenaria A2-J used in this study showed M. javanica and/or M. incognita -like perineal patterns, the A2 pattern in esterase isozyme, and approx. 1.7 kb amplicon. We then carried out a phylogenetic analysis based on the sequences of a partial region of COXII-IrDNA in mitochondrial DNA to reveal the relationships between M. arenaria A2-J and related species using corresponding sequences of Meloidogyne accessions deposited in GenBank. Moreover, host suitability of representative Solanaceae plants including Solanum torvum was evaluated and compared to those of major species of Meloidogyne collected from Japan.