Molecular and morphological characterization of the spiral nematode Helicotylenchus oleae Inserra, Vovlas & Golden, 1979 (Nematoda: Hoplolaimidae) in the Mediterranean Basin

The spiral nematode Helicotylenchus oleae is an ectoparasite of olive roots and is distributed in some countries in the Mediterranean Basin. In this study, we provided morphological and molecular characterisation of topotypes from southern Italy, as well as of several other populations from Crete (Greece) and Spain. Correct identification of plant-parasitic nematode species is essential to establish appropriate control strategies and for preventing their spread to other areas. Helicotylenchus oleae is reported for the first time in Greece (Crete). Integrative morphometric and molecular data for H. oleae populations using D2-D3 expansion segments of 28S rDNA, ITS-rDNA, and the cytochrome c oxidase subunit 1 (coxI), were in agreement with the original descriptions of the species, except for some minor differences, which may be a result of intraspecific variability. The phylogenetic relationships of this species with other representatives of Helicotylenchus spp. using D2-D3 expansion segments and the ITS-rRNA region was studied showing a low intraspecific diversity for H. oleae species. For the first time, coxI molecular data is obtained for the genus Helicotylenchus.This research was supported by grant P12-AGR 1486 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, ‘Una manera de hacer Europa’, grant 201740E042, "Análisis de diversidad molecular, barcoding, y relaciones filogenéticas de nematodos fitoparásitos en cultivos mediterráneos" from Spanish National Research Council (CSIC), grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the Mediterranean basin’ from Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and AGL-2012-37521 from ‘Ministerio de Economía y Competitividad’ of Spain.Peer reviewe