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

Abstract

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.

Rotylenchus dalikhaniensis n. sp. (Nematoda: Hoplolaimidae), a monosexual species recovered from the rhizosphere of Ruscus hyrcanus Woronow in Mazandaran province, northern Iran

“…As in recent contributions (Cantalapiedra-Navarrete et al, 2012, 2013, the phylogenetic relationship showed that R. conicaudaus (HQ700698) formed a clade with two species of Helicotylenchus and occupied a paraphyletic position. This phylogenetic tree clearly showed the paraphyly of the Hoplolaimidae as previously docu mented by other authors (Subbotin et al, 2007;Vovlas et al, 2008;Atighi et al, 2011;Cantalapiedra-Navarrete et al, 2012, 2013. Figure 6 presents a phylogenetic tree constructed using ITS 1 sequence of the new species and 42 species of Rotylenchus and one belonolaim as outgroup taxon.…”

“…Primers for 28S rRNA gene D2-D3 amplification were forward primer D2a (5'-ACAAGTACCGTGAGGGAAAGT-3') and re verse primer D3b (5'-TGCGAAGGAACCAGCTACTA-3') (Nunn, 1992). The forward primer TW81 (5'-GTTTC CGTAGGTGAACCTGC-30 and reverse primer 5.8SM5 (5'-GGCGCAATGTGCATTCGA-3') were used for am plification of the ITS 1-rRNA gene (Vovlas et al, 2008). PCR was carried out in a total volume of 30 /i\ (16.7 /A distilled water, 3 /A lOx PCR buffer, 0.6 /A 10 mMd NTP mixture, 1.2 /A 50 mM MgCl2 , 1.5 /A of each primer (lOpmol /xl-1), 0.5 /A of Taq DNA polymerase (5U /A~x, CinnaGen) and 5 /A of DNA template).…”

“…The large number of species within Rotylenchus Filipjev, 1936 (ca 97 nominal species) complicates the identification process. Recently, DNAbased approaches have been successfully used for the molecular diagnostics of Rotylenchus (Vovlas et al, 2008;Atighi et al, 2011;Cantalapiedra-Navarrete et al, 2013). Phylogenetic studies within the genus have been carried out based on the D2-D3 expansion region of the 28S and ITSl-rRNA genes, providing initial insight toward resolving phylogenetic relationships among Rotylenchus species and other genera, and demonstrating paraphyly of the genus in the majority rule consensus trees within Hoplolaimidae (Subbotin et al, 2007;Vovlas et al, 2008).…”

Molecular characterization of Xiphinema brevicollum (Nematoda: Longidoridae) from the Czech Republic

“…Molecular features are considered to be particularly useful where morphological characters lead to an ambiguous interpretation or when dealing with cryptic species which are clearly different based on their genes, but are difficult to distinguish based on morphological characteristics (Tandingan De Ley et al 2007;Vovlas et al 2008). Since the identification of X. brevicollum is controversial and morphological analysis (e.g.…”

Description of Rotylenchus arasbaranensis n. sp. from Iran with discussion on the taxonomic status of Plesiorotylenchus Vovlas, Castillo & Lamberti, 1993 (Nematoda: Hoplolaimidae)

“…The large num ber of species within the genus (ca 95 nominal species) complicates the identification process and has required the construction of tabular and dichotomous keys, based on a combination of major and supplementary characters, to enable pragmatic morphological identification (Castillo & Vovlas, 2005). Recently, DNA-based approaches have been successfully used for the molecular diagnostics of species of Rotylenchus (Vovlas et al, 2008;Atighi et al, 2011;Cantalapiedra-Navarrete et al, 2013). Phylogenetic studies within Rotylenchus have been carried out based on the D2-D3 expansion region of the 28S and ITS1 rRNA genes, providing initial insights toward resolving phylogenetic relationships among Rotylenchus species, and demonstrating paraphyly of the genus in the majority rule consensus trees within Hoplolaimidae Filipjev, 1934(Subbotin et al, 2007Vovlas et al, 2008;CantalapiedraNavarrete et al, 2012).…”