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.

根结线虫属寄生并引起寄主根部的伤毛，造成严重的产量损失。沙根结线虫(Neal 1889) Chitwood 1949 是主要种类之一，发现于日本，可分为两种基因型：沙线根结线虫A2-J 和 A2-O。后者是典型的M. arenaria，而前者在形态和遗传上被经验地认为是非典型的，但其详细特征和系统发育关系尚未描述。首先，我们使用M. arenaria A2-J的C2F3/1108引物组检查了会阴模式、同工酶模式和PCR产物，并确认本研究中使用的所有M. arenaria A2-J群体均显示M. javanica和/或M. incognita样会阴模式，酯酶同工酶中的 A2 模式，以及大约。 1.7 kb 扩增子。然后，我们基于线粒体DNA中COXII-IrDNA的部分区域的序列进行了系统发育分析，利用GenBank中保藏的根结线虫种质的相应序列揭示了M. arenaria A2-J与相关物种之间的关系。此外，还评估了包括托鲁巴姆在内的代表性茄科植物的寄主适宜性，并将其与从日本收集的 根结线虫主要物种的寄主适宜性进行了比较。