Molecular and morphological delineation of Longidorus poessneckensis Altherr, 1974 (Nematoda: Dorylaimida)

The plant-parasitic nematode Longidorus poessneckensis from the Czech Republic was morphologically and molecularly characterised. Molecular analyses were carried out using mitochondrial DNA (cytochrome c oxidase subunit 1-cox1) and ribosomal DNA (ITS2-second internal transcribed spacer, 18S gene and D2/D3 expansion segments of the 28S gene), which were amplified and sequenced. Phylogenetic relationship of L. poessneckensis with three morphologically closely related species, i.e. L. macrosoma, L. helveticus and L. uroshis, was inferred by using maximum likelihood and maximum parsimony methods, with a female of Xiphinema diversicaudatum and a bivulval female of X. vuittenezi as outgroups. All multiple alignments yielded similar basic trees supporting the uniqueness of L. poessneckensis and the validity of the four Longidorus species identified using morphological characters. Phylogenetic analyses revealed that L. poessneckensis is more closely related to L. macrosoma and L. helveticus than to L. uroshis. High inter-population diversity (19%) was observed across the cox1 gene between two populations of L. poessneckensis.