First report, morphological and molecular characterization of Xiphinema elongatum and X. pachtaicum (Nematoda, Longidoridae) from Ethiopia

A total of six soil samples were collected around rhizosphere of citrus plants during 2010 from Melkassa Agricultural Research Center experimental station, Ethiopia. From these samples two most important ecto-plant parasitic nematodes of the genus Xiphinema were found and analysed. The genus Xiphinema is a large group of the phylum nematoda which constitutes more than 260 species. They are polyphagous root- ectoparasites of many crop plants and some species of this genus cause damage by direct feeding on root tips and transmit nepoviruses. The delimitation and discrimination of two species in the genus is presented, described herein as Xiphinema elongatum and Xiphinema pachtaicum. Morphological and morphometric data were done using light microscopy and results of both species were fit within the previously described nematode species of X. elongatum and X. pachtaicum. 18S rDNA were analysed using Bayesian inference (BI) method to reconstruct phylogenetic relationships of the studied Xiphinema sp. (KP407872 X. elongatum and KP407873 X. pachtaicum) with other Xiphinema species. The 18S rDNA sequence of X. pachtaicum was alike to previously described species from the GenBank but X. elongatum exhibited very small levels of nucleotides differences (0.4%) which might be possible intra-specific divergence. Though this region of rDNA has less resolution on complex species, its combination with morphological and morphometric analyses, suggests these species as X. elongatum and X. pachtaicum with the GenBank accession number of KP407872 and KP407873, respectively. Short notes, morphological measurements, illustrations, and molecular data are given to these species. These species are reported for the first time from Ethiopia and it provides new geographical information of these organisms.