Molecular biodiversity assessment of plant-parasitic nematodes in Dokdo Island, Korea

Dokdo Island has a unique biodiversity that has been preserved as a natural monument. Although the biodiversity of Dokdo has been investigated, little information is available regarding the nematodes. The diversity of plant-parasitic nematodes was investigated using both ITS and D2-D3 sequences. Nematodes extracted from 59 rhizosphere soil samples were morphologically identified as belonging to eight genera: Geocenamus, Helicotylenchus, Rotylenchulus, Heterodera, Paratylenchus, Pratylenchus, Pratylenchoides and Xiphinema. Further, nucleotide sequences were determined from 85 individuals of different genera for species diagnosis. We identified 13 species, including three species of the genus Pratylenchus (P. crenatus, P. kumamotoensis and P. neglectus), Helicotylenchus sp. 1, Rotylenchulus sp. 1, Paratylenchus nanus, Heterodera trifolii, Heterodera spp., Pratylenchoides ritteri, Geocenamus sp. 1, Geocenamus sp. 2, Xiphinema brevicollum and Xiphinema sp. 1. The dominant plant-parasitic nematode on Dokdo was P. crenatus, which was found in 25.4% of the samples. Our study provides important information about the biodiversity of plant-parasitic nematodes on Dokdo Island.