A new species of the genus Xiphinema Cobb 1913 (Nematoda: Longidoridae) from north and northwest Iran

European Journal of Plant Pathology - Five populations of a new dagger nematode species were recovered from natural grasslands and forests of north and northwest Iran, and described based upon...     

Correction to: A new species of the genus Xiphinema Cobb 1913 (Nematoda: Longidoridae) from north and Northwest Iran

European Journal of Plant Pathology - A Correction to this paper has been published: https://doi.org/ https://doi.org/10.1007/s10658-021-02272-1     

Characterization of Longidorus helveticus (Nematoda: Longidoridae) from the Czech Republic

Longidorus helveticus was found at two out of 285 sampling sites for the first time in the Czech Republic. Females, males and juvenile stages were analyzed morphologically and morphometrically. The morphological identification of samples was verified by polymerase chain reaction using a species specific primer. Four markers of ribosomal DNA (18S, ITS1, ITS2, D2-D3 expansion segments of 28S rRNA) and two markers of mitochondrial DNA (cox1 and nad4) were sequenced and analyzed and compared with published gene sequences of other populations of L. helveticus. The partial mitochondrial cytochrome c-oxidase subunit 1 gene and partial nicotinamide dehydrogenase subunits 4 gene showed relatively high genetic variation within the species compared with ribosomal DNA markers.     

Molecular characterization of <Emphasis Type="Italic">Xiphinema brevicollum</Emphasis> (Nematoda: Longidoridae) from the Czech Republic

Populations of Xiphinema brevicollum occurring in the Czech Republic were described morphologically and molecularly. Published species-specific primer set BL18 and BV3 was used to amplify three populations of X. brevicollum from the Czech Republic. These primers were tested against 9 species of Xiphinema and 11 species of Longidorus. Amplification was also observed for X. inaequale, X. italiae and X. lambertii. Three additional markers, mitochondrial cytochrome c oxidase subunit 1, ribosomal D2/D3 expansion segment of the 28S gene and 18S gene, were amplified and sequenced for X. brevicollum, X. inaequale and X. lambertii belonging to X. americanum-group. Comparison of cox1 sequences of X. brevicollum from the Czech Republic with X. taylori from the Slovak Republic (accession number AM086702) suggested that these populations represent the same species.     

The relationship between species within the Xiphinema americanum-group (Nematoda: Dorylaimida)1

Principal components and hierarchical cluster analysis based on morphometric characters of the type populations of the 39 species attributed to the Xiphinema americanum-group confirmed the occurrence of five subgroups. The use of a single character is generally insufficient to characterize a species because of the wide intra-population and intra-specific variations. Hierarchical cluster analysis, although impractical for species/population identification, appears useful in the study of the relationships between species or groups of species.     

Morphological and molecular characterisation of Longidorus sabalanicus n. sp. (Nematoda: Longidoridae) from Iran

European Journal of Plant Pathology - The effects of three biological control agents (BCAs) including Funneliformis mosseae BEG12 (FM) as arbuscular mycorrhizal fungi (AMF), Bacillus velezensis...     

Phylogeny, diversity, and species delimitation in some species of the Xiphinema americanum-group complex (Nematoda: Longidoridae), as inferred from nuclear and mitochondrial DNA sequences and morphology

During nematode surveys in southern Spain and Italy 14 populations of Xiphinema species tentatively identified as Xiphinema americanum-group were detected. Morphological and morphometrical studies identified three new species and six known Xiphinema americanum-group species, viz.: Xiphinema parabrevicolle n. sp., Xiphinema parapachydermum n. sp., Xiphinema paratenuicutis n. sp., Xiphinema duriense, Xiphinema incertum, Xiphinema opisthohysterum, Xiphinema pachtaicum, Xiphinema rivesi, and Xiphinema santos. The Xiphinema americanum-group is the most difficult Xiphinema species group for diagnosis since the morphology is very conservative and morphometric characters often overlap. This group includes vectors of several important plant pathogenic viruses that cause significant damage to a wide range of agricultural crops. Molecular characterisation of these species using D2-D3 expansion regions of 28S rRNA, 18S rRNA, ITS1-rRNA and the protein-coding mitochondrial gene, cytochrome oxidase c subunit 1 was carried out and maximum likelihood and Bayesian inference analysis were used to reconstruct phylogenetic relationships among these species and with other Xiphinema americanum-group species.     

Molecular characterisation and diagnostics of some Longidorus species (Nematoda: Longidoridae) from Russia and other countries using rRNA genes

The needle nematodes of the genus Longidorus can cause diseases of various crops and trees, and are comprised of more than 150 valid species. Eleven valid and six unidentified species of the genus Longidorus collected in different regions of Russia, two states of USA, Germany, New Zealand and Ukraine were molecularly characterized using analysis of the partial 18S rRNA and the D2–D3 expansion segments of the 28S rRNA gene sequences. Fifty-four partial 28S rRNA and fifteen partial 18S rRNA gene sequences were obtained for the present study. Using molecular criteria, we confirmed the morphological identification and distinguished between the following species: L. aetnaeus, L. africanus, L. andalusicus, L. artemisiae, L. caespiticola, L. distinctus, L. elongatus, L. euonymus, L. intermedius, L. leptocephalus and L. lignosus. Two longidorid populations from Russia and four from California were not identified to a species level. We obtained the full length D2–D3 of 28S rRNA gene sequence from several freshly-collected L. artemisiae samples. We confirmed the identity of the D2 region of 28S rRNA gene sequence with a short D2 of 28S rRNA gene fragment sequence previously obtained from formalin-fixed nematodes embedded in the L. artemisiae paratype slides. Longidorus lignosus was molecularly characterized and L. aetnaeus was reported from Russia for the first time. PCR-D2-D3-RFLP diagnostic profiles generated by five restriction enzymes: AluI, HinfI, Bsp143I, Tru1I and RsaI are presented for sixteen Longidorus species.     

Integrative diagnosis and molecular phylogeny of dagger and needle nematodes of olives and grapevines in the island of Crete,Greece, with description of Xiphinema cretense n. sp. (Nematoda,Longidoridae)

The occurrence and geographic distribution of longidorid nematode species inhabiting the rhizosphere of cultivated and wild olive and grapevine in Crete Island were investigated. Morphological and morphometrical studies identified five Longidorus and six Xiphinema species, with frequencies of prevalence (for wild and cultivated olives and grapevines, respectively) as follows: Longidorus closelongatus (2.0–13.3 %), L. cretensis (1.0–6.7 %), L. moesicus (13.3 % only in grapevines), L. orientalis (3.3 % only in grapevines), L. pseudoelongatus (7.0 % only in olives), Xiphinema cretense n. sp. (3.0 % only in olives), X. index (3.0–23.3 %), X. israeliae (6.3 % only in olives), X. italiae (3.3–10.0 %), X. pachtaicum (26.7–42 %) and X. simile (3.3 % only in grapevines). Xiphinema cretense n. sp. is characterized by a body size 3,872–6,135 μm long, lip region anteriorly rounded, separated from the rest of the body by a depression, odontostyle and odontophore 140.6 and 80.3 μm long respectively, vulva position at 46.0–50.5 %, female tail 31.0–38.0 μm long, nearly hemispherical with curvature essentially dorsal and with a tip completely rounded or presenting a very short bulge, c ratio (119.1–186.9), c’ ratio (0.7–0.8). Molecular characterisation using D2-D3 expansion regions of 28S rRNA, 18S rRNA and ITS1-rRNA was carried out and maximum likelihood and Bayesian inference analysis were used to reconstruct phylogenetic relationships among these species and with other longidorids.     

Cytochrome c oxidase subunit 1 analysis of <Emphasis Type="Italic">Xiphinema diversicaudatum,X. pachtaicum,X. simile</Emphasis> and <Emphasis Type="Italic">X. vuittenezi</Emphasis> (Nematoda,Dorylaimida)

Genetic analyses using sequences of partial cytochrome c oxidase subunit 1 (cox1) gene of mitochondrial DNA were conducted to determine the extent of genetic variation within and among Xiphinema diversicaudatum, X. pachtaicum, X. simile and X. vuittenezi populations. Pairwise distance among the four species was 22.5 to 31.2%. Four different sequence variants of cox1 were determined among six populations of X. diversicaudatum and three variants among three populations of X. simile. Nucleotide variation was detected at 18 of 414 bp (1.9 to 2.7%) in X. diversicaudatum and 4 of 435 bp (0.2 to 0.9%) in X. simile. All changes were at silent sites. No nucleotide variation was detected within three populations of X. pachtaicum and within three populations of X. vuittenezi.     

PM 7/95 (2): Xiphinema americanum sensu lato

Specific scope

This Standard describes a diagnostic protocol for Xiphinema americanum sensu lato 1 . This Standard should be used in conjunction with PM 7/76 Use of EPPO diagnostic protocols. Terms used are those in the EPPO Pictorial Glossary of Morphological Terms in Nematology 2 .

Specific approval and amendment

Approved in 2009‐09. Revised in 2017‐01. This revision was prepared on the basis of the IPPC Diagnostic Protocol adopted in 2016 (Annex 11 to ISPM 27, IPPC, 2016). This EPPO Diagnostic Standard differs in terms of format but it is consistent with the content of the IPPC Standard. However, since the adoption of the IPPC Protocol 5 new species have been added into the group and are included in this version of the EPPO Protocol.     

PM 7/95(1): Xiphinema americanum sensu lato

Specific scope

This standard describes a diagnostic protocol for Xiphinema americanum sensu lato ¹ 1 Use of names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

Approved in 2009–09.

     

Description of Longidorus armeniacae n. sp. (Nematoda: Longidoridae), associated with Prunus armeniaca L. in Semnan province,Iran

European Journal of Plant Pathology - Longidorus armeniacae n. sp. is described and illustrated using morphological and molecular data. It was recovered from the rhizosphere of apricot trees in...     

Frequency of transmission of artichoke Italian latent nepovirus by Longidorus fasciatus (Nematoda: Longidoridae) from artichoke fields in the Iria and Kandia areas of Argolis in northeast Peloponnesus, Greece

Artichoke Italian latent nepovirus (AILV) transmitted by Longidorus fasciatus is a causative agent of artichoke patchy chlorotic stunting (APCS) in northeast Peloponnesus in southern Greece. Populations of L. fasciatus collected from the Iria and Kandia areas of Argolis in northeast Peloponnesus were used in laboratory experiments to determine the frequency of transmission of the virus by its natural vector. One tenth to almost one half of the L. fasciatus specimens recovered from soil collected in two artichoke fields showing APCS transmitted AILV. Allowing nematodes access for 4 wk to Nicotiana clevelandii mechanically infected with AILV did not increase the number of individual specimens able to transmit virus. The total number of specimens transmitting virus in an experiment did not exceed fifty percent of the individuals tested. Virus-like particles were only observed adsorbed to the inner surface of the odontostyle and it is suggested that the high frequency of transmission of AILV by L. fasciatus is a result of efficient dissociation of virus particles from the specific sites of retention in the vector.     

The life cycle of Dichelyne (Cucullanellus) minutus (Nematoda: Cucullanidae)

Mature specimens of the nematode Dichelyne (Cucullanellus) minutus (Rudolphi, 1819) (Ascaridida, Cucullanidae, Seuratoidea) were obtained from the intestine of flounder Platichthys flesus (L.) caught in the Oresund, Denmark. Plaice Pleuronectes platessa L. and common goby Pomatoschistus microps (Kr?yer) also harbour this species. The eggs embryonate on the seabottom. Larvae about 440 microm long, and believed to be in their third stage, hatch from the eggs. These larvae are not directly infective to flounders or gobies. The polychaete Nereis diversicolor O.F. Muller acts as obligatory intermediate host. Experimental infections showed that larvae >600 microm long and provided with achitinous tooth survived in flounder and common goby. The third-stage larvae moult to fourth-stage larvae in the fish gut wall. Mature worms occur in the lumen of the anterior part of the intestine. All developmental stages may be transferred from one flounder to another; thus the flounder may acquire the parasite also by devouring infected gobies.