Distribution and diversity of root-lesion nematodes (Pratylenchus spp.) associated with Ammophila arenaria in coastal dunes of Western Europe

The distribution and diversity of Pratylenchus species associated with Ammophila arenaria was investigated in its natural range of distribution. Twelve localities with vigorous stands of A. arenaria along the European Atlantic and Mediterranean coasts were sampled. The populations were identified based on morphology and morphometrics, and further characterised based on sequences of the rDNA D2D3 region. Pratylenchus spp. were present in all of the sampled sites. A total of 19 populations were detected belonging to Pratylenchus dunensis, P. brzeskii, P. pratensis or P. penetrans. Pratylenchus dunensis was widely distributed from Blakeney Point (UK) to Comporta (Portugal). Pratylenchus brzeskii was found in South European localities along the Atlantic coast and also in the Mediterranean region. Pratylenchus pratensis was found associated with A. arenaria for the first time and occurred at different locations along the Atlantic coast. Pratylenchus penetrans was only detected in Biarritz (France). The P. dunensis populations from the south west Iberian Peninsula differed from the original P. dunensis description and showed two incisures on the lip region instead of one. Pratylenchus brzeskii populations did not vary morphologically from the original descriptions; however, the range of their morphometrical characters was wider than that of the type population. The D2D3 rDNA region revealed large interspecific and low intraspecific variation, supporting the morphological identification. The phylogenetic relationships of the populations with respect to other species of the genus were inferred from partial sequences of the rDNA and positioned P. dunensis within the same group as P. convallariae, P. penetrans and P. fallax