Morphological and molecular characterisation of Paralongidorus plesioepimikis n. sp. (Nematoda: Longidoridae) from southern Spain

Abstract

25Paralongidorus plesioepimikis n. sp. from Spain 2 Summary -Paralongidorus plesioepimikis n. sp. is described and illustrated by light 1 microscopy, scanning electron microscopy and molecular studies from specimens collected in 2 a sandy soil in the rhizosphere of stone pine (Pinus pinea) in Bonares (Huelva Province), 3 southern Spain. The new species is characterised by a very long body (9.71-14.11 mm), a 4 rounded lip region, with a clear constriction followed by a depression posterior to the 5 amphidial aperture, a very long and flexible odontostyle (202-227 µm), guiding ring located 6 at 36.5-44.0 m from anterior end, dorsal pharyngeal gland nucleus in anterior part of bulb, 7 one subventral pair of nuclei near middle of bulb, vulva at 33-38%, and a dorsally convex tail 8 with rounded terminus (32-39 m long). SEM observations showed a very large amphidial 9 fovea with conspicuous aperture ca three-fourths as wide as lip region and cephalic papillae 10 appearing as small apertures, each located just anterior to a distinct cephalic lobe. The 11 sequences of the D2-D3 expansion segments of 28S rRNA, partial 18S rRNA and ITS rRNA 12 gene for P. plesioepimikis n. sp. were obtained. Phylogenetic analyses of P. plesioepimikis n. 13 sp. rRNA gene sequences and of Paralongidorus spp. and Longidorus spp. sequences 14 published in GenBank were done using Maximum Likelihood and Bayesian inference. 15Paralongidorus species (including P. plesioepimikis n. sp.) clustered together, except for P. 16 bikanerensis which clustered within Longidorus spp. and was clearly separated from all other 17Paralongidorus spp. in trees generated from the D2-D3 expansion segments of 28S and 18 partial 18S data set. ML analysis using SH-test for the validity of Paralongidorus was 19 performed and showed the validity of the genus using the D2-D3 expansion segment of 28S 20 and partial 18S. 21 22

An update on the genus Longidorus, Paralongidorus and Xiphinema (Family Longidoridae) in Portugal

“…Macara (1994) reported a large list of populations belonging to the X. diversicaudatum complex, but unfortunately did not include any detailed morphometric and morphological characterizations. Results of the D2-D3 region of 28S gene obtained by Gutiérrez-Gutiérrez et al (2013) during a morphological and molecular phylogenetic study of subfamily Xiphineminae species belonging to the X. diversicaudatum complex suggest that the population of X. diversicaudatum (GenBank accession number: AY601624) from northern Portugal, which was not identified on the basis of detailed morphological and morphometric analysis, was a misidentification and should be considered conspecific with X. coxi europaeum Sturhan, 1984. Subsequently, the phylogenetic analysis developed by Chizhov et al (2014), during a polyphasic study based on morphological and molecular data where several new Central European X. diversicaudatum populations were incorporated, is in agreement with the idea of Gutiérrez-Gutiérrez et al (2013b) regarding a misidentification of the Portuguese population (GenBank accession number: AY601624) which should be considered as X. coxi europaeum.…”

Morphological and molecular characterisation of Paralongidorus rex Andrássy, 1986 (Nematoda: Longidoridae) from Poland and Ukraine

“…The new sequences of the 18S rRNA, D2-D3 of 28S rRNA and ITS1 rRNA genes were aligned using ClustalX 1.83 with default parameters with their corresponding published gene sequences (He et al 2005;Palomares-Rius et al 2008, 2013Pedram et al 2012).…”

Description and molecular phylogeny of one new and one known needle nematode of the genus Paralongidorus (Nematoda: Longidoridae) from grapevine in Portugal using integrative approach

“…The taxonomic and systematic position of the genus Paralongidorus Siddiqi, Hooper & Klan, 1963 within the family Longidoridae (Thorne, 1935) Meyl, 1961 appears to be accepted by the scientific community, however the species composition are continuously being subject of debate (Hunt 1993, Siddiqi et al 1993, Coomans 1996, Escuer & Arias 1997, Decraemer & Robbins 2007. This genus, member of the commonly known needle nematodes, is quite diverse with about 90 valid species of migratory ectoparasites that parasitise a wide range of agronomic crops, ornamentals, and forest trees (Taylor & Brown 1997, Decraemer & Robbins 2007, Palomares-Rius et al 2013, Kornobis et al 2015, Barsi & De Luca 2017. This group of phytopathogenic species are of global interest because they cause directly damage on the roots of the host plant attributable to their ectoparasitic feeding and one species is able to transmit damaging nepoviruses (Taylor & Brown 1997, Decraemer & Robbins 2007.…”

“…Morphometric and morphological identification within this genus at species level is mainly based on characteristics of adult females (Escuer & Arias 1997).However, the high intraspecific variability of some diagnostic features and the great diversity in phenotypic plasticity make species identification based on gross morphology and internal anatomical features a technically difficult task even for experts. Recently, the sequencing of RNA-based markers is an increasingly powerful approach for the molecular diagnostics and for understanding their inter-and intra-genetic variability (Palomares-Rius et al 2013, Kornobis et al 2015, Barsi & De Luca 2017. Several ribosomal RNA (rRNA) genes are used for molecular characterizations of these nematodes: partial 28S rRNA gene (He et al 2005, Palomares-Rius et al 2008, Pedram et al 2012, Kornobis et al 2015, Barsi & De Luca 2017, 18S rRNA gene (Palomares-Rius et al 2008, Pedram et al 2012, Kornobis et al 2015 and internal transcribed spacer (ITS) region of the rRNA genes (Palomares-Rius et al 2008, Pedram et al 2012, Kornobis et al 2015, Barsi & De Luca 2017.…”

“…in Europe and it is frequently found parasitizing a large number of forest trees, grapevine, chestnut tree (Castanea spp. ), walnut trees (Juglans regia L.) and a wide range of vegetable crops in Europe (Heyns, 1975;Lamberti et al, 1983;Roca et al 1988;Macara 1994;Lišková, 1995;Bravo & Lemos 1997;Taylor & Brown 1997;Lišková & Brown, 1998, 1999Gutiérrez-Gutiérrez et al 2016), ii) P. iberis Dalmasso, 1969 in grapevine in Algeria (Dalmasso 1969), vi) P. plesioepimikis Palomares-Rius, Cantalapiedra-Navarrete, Gutiérrez-Gutiérrez, Liébanas & Castillo, 2013 in the rhizosphere of stone pine (Pinus pinea L.) in Spain (Palomares-Rius et al 2013), vii) P. georgiensis (Tulaganov, 1937) Luc & Doucet 1984, in a vegetable garden soil in Egypt (Tulaganov 1937), viii) P. remeyi Altherr 1963 in an unknown host in France (Altherr, 1963), ix) P. rex is commonly found infesting grapevine and oak forest in Hungary (Andrássy 1986, Barsi et al 2007), forest tree species and grasses in Poland and Ukraine (Kornobis et al 2015), and x) P. francolambertii in the rhizosphere of silver lime trees (Tilia tomentosa Moench) and juniper trees (Juniperus communis L.) in a forest in Serbia (Barsi & De Luca 2017). In Europe the low species diversity of Paralongidorus and Longidorus and their current geographical distribution can be attributed to their center of origin, which is supposed to be located in South African-Indian division when it was only one supercontinent (Pangea), before the separation of major plate tectonics (Coomans,1985).…”