Description of the first-stage juveniles of Xiphinema cretense and X. herakliense - Distribution of Xiphinema and Longidorus species in olive orchards and grapevines in Crete, Greece

The occurrence of nematodes of the family Longidoridae was investigated in soil samples collected from cultivated and wild olives and grapevines in Crete. The first-stage juveniles of Xiphinema cretense and X. herakliense are described for the first time. The species X. israeliae, X. cretense, X. herakliense and Longidorus pseudoelongatus, previously recorded exclusively from olives in Crete, are herein reported in the rhizosphere of grapevines. Also L. iranicus is reported for the first time in cultivated olive, while X. italiae and L. closelongatus are reported for the first time in wild olive in Crete. Data on the occurrence of phytoparasitic nematode species in cultivated olives, wild olives and grapevines are updated with those previously published.This research was supported by 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), grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, “Una manera de hacer Europa”. I.G. Birmpilis and E. Nasiou were employed by the ARIMNET-PESTOL-IVE project.Peer reviewe

Unravelling the Biodiversity and Molecular Phylogeny of Needle Nematodes of the Genus Longidorus (Nematoda: Longidoridae) in Olive and a Description of Six New Species

The genus Longidorus includes a remarkable group of invertebrate animals of the phylum Nematoda comprising polyphagous root-ectoparasites of numerous plants including several agricultural crops and trees. Damage is caused by direct feeding on root cells as well as by transmitting nepoviruses that cause disease on those crops. Thus, correct identification of Longidorus species is essential to establish appropriate control measures. We provide the first detailed information on the diversity and distribution of Longidorus species infesting wild and cultivated olive soils in a wide-region in southern Spain that included 159 locations from which 449 sampling sites were analyzed. The present study doubles the known biodiversity of Longidorus species identified in olives by including six new species (Longidorus indalus sp. nov., Longidorus macrodorus sp. nov., Longidorus onubensis sp. nov., Longidorus silvestris sp. nov., Longidorus vallensis sp. nov., and Longidorus wicuolea sp. nov.), two new records for wild and cultivate olives (L. alvegus and L. vineacola), and two additional new records for wild olive (L. intermedius and L. lusitanicus). We also found evidence of some geographic species associations to western (viz. L. alvegus, L. intermedius, L. lusitanicus, L. onubensis sp. nov., L. vineacola, L. vinearum, L. wicuolea sp. nov.) and eastern distributions (viz. L. indalus sp. nov.), while only L. magnus was detected in both areas. We developed a comparative study by considering morphological and morphometrical features together with molecular data from nuclear ribosomal RNA genes (D2–D3 expansion segments of 28S, ITS1, and partial 18S). Results of molecular and phylogenetic analyses confirmed the morphological hypotheses and allowed the delimitation and discrimination of six new species of the genus described herein and four known species. Phylogenetic analyses of Longidorus spp. based on three molecular markers resulted in a general consensus of these species groups, since lineages were maintained for the majority of species. This study represents the most complete phylogenetic analysis for Longidorus species to date.Financial support was received by Projects AGL-2012-37521 from ‘Ministerio de Economía y Competitividad’ of Spain, Project P12-AGR-1486 from ‘Consejería de Economía, Innovación y Ciencia’ of Junta de Andalucía, and FEDER financial support from the European Union is gratefully acknowledged. The grant 219262 ArimNET_ERANET FP7 2012–2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the Mediterranean basin’ from Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), also provided partial financial support.Peer reviewe

Barcoding de nematodos fitoparásitos

Trabajo presentado en la III Reunión Grupo Especializado en Detección, Diagnóstico e Identificación de la Sociedad Española de Fitopatología (GEDDI-SEF), celebrado en Valencia (España) del 28 al 30 de noviembre de 2017.La identificación tradicional de especies de nematodos fitoparásitos mediante estudios de morfología y morfometrla es complicada por la presencia de una alta variabilidad morfológica que puede incidir en un gran solapamiento de muchos caracteres provocando una interpretación ambigua de éstos para el diagnóstico de especies. En muchos casos existe la presencia de especies crípticas (muy similares morfométricamente, pero distintas molecularmente) que hacen necesaria la utilización de marcadores moleculares conservados (generalmente ribosómicos o mitocondriales) que permiten la correcta identificación de dichas especies. Por este motivo, es necesario integrar la morfología y morfometría con marcadores moleculares apropiados en un contexto de ''taxonomía integrativa". En este contexto las técnicas de barcoding para distintos marcadores moleculares pueden ayudar a la identificación de especies tanto en estudios rutinarios de poblaciones de campo como en estudios de meta-barcoding de suelo. Los genes ribosómicos (18S, región 02-03 del gen 28S y la región intergénica de separación de genes ribosómicos(ITS)) y algunos marcadores moleculares del ADN mitocondrial (cox/y cytB) parecen ser buenos marcadores para la identificación y filogenia en nematodos. La familia Longidoridae comprende importantes especies de nematodos fitoparásitos, tanto por su parasitismo al alimentarse de las ralees de las plantas, como por ser transmisores de algunas especies de nepovirus. Dentro de esta familia, hay claros ejemplos de especies crípticas y de grupos de especies con escasas diferencias morfológicas entre sí, pero con importantes características fitopatológicas (p. ej. transmisión de virus), lo que lo hace ser un buen ejemplo para integrar estas técnicas de taxonomía integratlva y barcoding. En este trabajo presentamos los resultados obtenidos en el análisis de 560 secuencias de la regiónD2-D3 y 253 secuencias parciales del gen cox/de nematodos de la familia Longidoridae (Xiphinema, Longidorus y Paralongidorus) y se discuten las potencialidades y debilidades de las técnicas de barcoding en la identificación de este grupo de nematodos.N

The utility of mtDNA and rDNA for barcoding and phylogeny of plant-parasitic nematodes from Longidoridae (Nematoda, Enoplea)

The traditional identification of plant-parasitic nematode species by morphology and morphometric studies is very difficult because of high morphological variability that can lead to considerable overlap of many characteristics and their ambiguous interpretation. For this reason, it is essential to implement approaches to ensure accurate species identification. DNA barcoding aids in identification and advances species discovery. This study sought to unravel the use of the mitochondrial marker cytochrome c oxidase subunit 1 (coxI) as barcode for Longidoridae species identification, and as a phylogenetic marker. The results showed that mitochondrial and ribosomal markers could be used as barcoding markers, except for some species from the Xiphinema americanum group. The ITS1 region showed a promising role in barcoding for species identification because of the clear molecular variability among species. Some species presented important molecular variability in coxI. The analysis of the newly provided sequences and the sequences deposited in GenBank showed plausible misidentifications, and the use of voucher species and topotype specimens is a priority for this group of nematodes. The use of coxI and D2 and D3 expansion segments of the 28S rRNA gene did not clarify the phylogeny at the genus level.This research was supported by grants P12-AGR 1486 and AGR-136 from the ‘Consejeria de Economia, Innovacion y Ciencia’ of the Junta de Andalucia, 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 219262 ArimNET_ERANET FP7 2012–2015 Project PESTOLIVE ‘Contribution of olive history for the management of soil-borne parasites in the Mediterranean basin’ from the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and Project AGL-2012-37521 from the ‘Ministerio de Economía y Competitividad’ of Spain.Peer reviewe

Plant-parasitic nematodes associated with cultivated and wild olive trees in Crete, Greece

The present study is part of a survey for the identification of plant-parasitic nematodes in the rhizosphere of cultivated and wild olive trees in Crete, Greece. Sixteen species corresponding to 13 genera are added to 20 species belonging to 8 genera, previously reported in the survey. Seven nematode species, Filenchus ditissimus, Filenchus vulgaris, Ogma civellae, Pratylenchoides crenicauda, Psilenchus hilarulus, Tylenchus elegans, and Zygotylenchus guevarai, are recorded for the first time in Greece.The present research was funded by grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the Mediterranean basin’ conducted by the Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, ‘Una manera de hacer Europa’