Molecular phylogeny of the genus Rotylenchus (Nematoda, Tylenchida) and description of a new species

17 pages, 8 figures.A description of a new species of plant parasitic nematodes of the genus Rotylenchus from the family Hoplolaimidae is given and a recognition of Rotylenchus jaeni comb. n., previously known as subspecies R. magnus jaeni, as separate species is proposed. Rotylenchus montanus sp. n. is characterized by a hemispherical lip region with six rarely seven annuli, stylet 33–37 µm, female tail rounded, regularly annulated tip with 12–18 annuli and phasmid located 2–9 annuli anterior to anus. Rotylenchus montanus sp. n. is close to species of the monosexual group R. arsenjevi, R. corsicus, R. fragaricus, R. helicus, R. indorobustus and R. neorobustus, by a number of specific characteristics resulting from its specific matrix code: A5, B1, C1, D4, E2, F2, G3, H2, I2, J2, K2. Molecular characterization of R. montanus sp. n. and other Rotylenchus species are provided using D2–D3 expansion segments of 28S and the ITS1 of rRNA genes. The D2–D3 of 28S rRNA and the ITS1–rRNA sequences of R. montanus sp. n. differed in one nucleotide and in 16–20 nucleotides from those of an unidentified Rotylenchus species from Russia, respectively. Molecular analysis of populations of R. magnus and R. jaeni comb. n. demonstrated differences in the D2–D3 and the ITS1–rRNA sequences. These genetic differences together with some minor morphological characters support that both subspecies should be considered as two cryptic sibling species and warranted their elevation to species rank. The result of phylogenetic analysis of Hoplolaimidae for 45 sequences of the D2 and D3 expansion regions of 28S rRNA gene using Bayesian inference analysis under the complex model is presented. Phylogenetic tree of Rotylenchus species represents seven moderate to highly supported lineages. Grouping of Rotylenchus species within other hoplolaimids and analysis of phylogenetic relationships within the genus Rotylenchus using the ITS1 of rRNA gene sequences are also discussed.The second author acknowledges support from NSF PEET grant DEB-0731516, and the fifth author acknowledges support from Consejería de Innovación Ciencia y Empresa (CICE) of Junta de Andalucía grant P06-AGR-01360.Peer reviewe

Integrative taxonomy and molecular phylogeny of the plant-parasitic nematode genus Paratylenchus (nematoda: paratylenchinae) : linking species with molecular barcodes

Pin nematodes of the genus Paratylenchus are obligate ectoparasites of a wide variety of plants that are distributed worldwide. In this study, individual morphologically vouchered nematode specimens of fourteen Paratylenchus species, including P. aculentus, P. elachistus, P. goodeyi, P. holdemani, P. idalimus, P. microdorus, P. nanus, P. neoamblycephalus, P. straeleni and P. veruculatus, are unequivocally linked to the D2-D3 of 28S, ITS, 18S rRNA and COI gene sequences. Combined with scanning electron microscopy and a molecular analysis of an additional nine known and thirteen unknown species originating from diverse geographic regions, a total of 92 D2-D3 of 28S, 41 ITS, 57 18S rRNA and 111 COI new gene sequences are presented. Paratylenchus elachistus, P. holdemani and P. neoamblycephalus are recorded for the first time in Belgium and P. idalimus for the first time in Europe. Paratylenchus is an excellent example of an incredibly diverse yet morphologically minimalistic plant-parasitic genus, and this study provides an integrated analysis of all available data, including coalescence-based molecular species delimitation, resulting in an updated Paratylenchus phylogeny and the corrective reassignment of 18 D2-D3 of 28S, 3 ITS, 3 18S rRNA and 25 COI gene sequences that were previously unidentified or incorrectly classified

Characterisation of a population of Pratylenchus hippeastri from bromeliads and description of two related new species, P. floridensis n. sp. and P. parafloridensis n. sp. from grasses in Florida

Morphological and molecular analyses confirmed the presence of P. hippeastri in regulatory samples collected in commercial bromeliad operations from genera Guzmania, Neoregelia and Vriesea in central and south Florida, USA. These P. hippeastri from bromeliads contained males which were not detected in the type population from amaryllis. The rDNA sequences of these males matched those of P. hippeastri female type material. Pratylenchus hippeastri and related root-lesion nematodes from several hosts in Florida were characterized at the morphological and molecular level, whereas other samples from Russia and South Africa at the molecular level only. Phylogenetic and sequence analysis using the ITS rRNA gene of these root-lesion nematodes revealed the presence of eight putative new species (spH1-H8) closely related to P. hippeastri. However, detailed morphological and molecular analyses are still required to confirm their unique species status. Here we describe two Florida representatives of the amphimictic root-lesion nematodes from Bahia grass (N1) and maidencane (N2), previously characterized by Inserra et al. (1996) and Duncan et al. (1999), as two new species phylogentically related to P. hippeastri and named Pratylenchus floridensis n. sp. and P. parafloridensis n. sp., respectively. The small round or oval, rarely rectangular and occasionally oblong and enlarged spermatheca and the bluntly pointed or subacute tail with smooth and occasionally indented terminus separate P. floridensis n. sp. from P. parafloridensis n. sp., which has a quadrangular spermatheca and a sub hemispherical or bluntly pointed tail with generally smooth and rarely indented terminus. However, these characters may overlap in some specimens making the morphological separation problematic without the use of molecular analysis. The close phylogenetic relationships shared by the species characterized in this study indicate that they are representatives of a P. hippeastri species complex