Occurrence of Cryptaphelenchus minutus and other nematode species associated with the bark of unidentified coniferous tree in Italy

During the inspection of vegetable material for EXPO 2015 in Milan (Italy), samples of bark from an unidentified coniferous tree were analysed and screened for the presence of the pinewood nematode, Bursaphelenchus xylophilus, in accordance with the surveillance of European Union to enable early detection and prevent further spread. In this study, nematodes associated with the bark of unidentified coniferous tree were collected and identified by morphometrics and sequencing of ITS, D2-D3 expansion domains of the 28S rRNA and the partial 18S rRNA genes. The sequences obtained and the phylogenetic analyses, using the ITS, D2-D3 expansion domains of the 28S rRNA and the partial 18S rRNA genes, revealed the presence of four Aphelenchidae species. Two of the species recovered were phylogenetically related to Cryptaphelenchus species. One of the two was identified as C. minutus, as it showed morphology and morphometry largely overlapping with Bursaphelenchus minutus, but phylogenetically closely related to Cryptaphelenchus species. The other three species recovered were only molecularly identified herein, by sequencing the ITS and the D2-D3 expansion domains, as Cryptaphelenchus sp. 1 and two Aphelenchoides species.

Automated summary

In this study, four nematode species were identified in bark samples from an unidentified coniferous tree, with one species closely related to the pinewood nematode but phylogenetically related to Cryptaphelenchus species.