Morphological and molecular analysis of six aphelenchoidoids from Australian conifers and their relationship to Bursaphelenchus (Fuchs, 1937)

Abstract

Six isolates of Australian Aphelenchoidoidea, viz., Laimaphelenchus preissii from native coniferous Callitris preissii trees, L. australis from the common pine plantation trees of Pinus radiata and P. pinaster and L. heidelbergi and two morphospecies of Aphelenchoides (H1 and K1) and Cryptaphelenchus sp. (K2) from diseased P. radiata trees, were studied using light microscopy, scanning electron microscopy and phylogenetic analyses of nearly full length sequences of SSU, D2/D3 expansion segments of LSU rDNA and a fragment of cytochrome oxidase subunit I (COI). Bayesian phylogenetic analyses of SSU, LSU and COI of the six nematode species revealed that none of these Australian aphelenchoidoids was inferred to be closely related to Bursaphelenchus. The selected isolates of Aphelenchoides and Laimaphelenchus used in this study were paraphyletic in all molecular analyses. Cryptaphelenchus sp. (K2) was inferred to be sister to Seinura with SSU sequences.

Description of Aphelenchoides macrospica n. sp. (Nematoda: Aphelenchoididae) from Northwestern Iran

“…is grouped with other genera of Aphelenchoidinae, i.e., Ficophagus Davies, Ye, Kanzaki, Bartholomaeus, Zeng, and Giblin-Davis, 2015, Martininema Davies, Ye, Kanzaki, Bartholomaeus, Zeng, and Giblin-Davis, 2015, Laimaphelenchus Fuchs, 1937, and Schistonchus s.s. Davies, Ye, Kanzaki, Bartholomaeus, Zeng, and Giblin-Davis, 2015, in clade 2. According to our molecular analysis, the members of the genus Aphelenchoides appears to be paraphyletic, a finding that agrees with previous studies (Zhao et al, 2008;Rybarczyk-Mydl À owska et al, 2012;Wang et al, 2013;Fang et al, 2014aFang et al, , 2014bMiraeiz et al, 2015;Esmaeili et al, 2016aEsmaeili et al, , 2016bGolhasan et al, 2016). Furthermore Aphelenchoides, Laimaphelenchus, and Schistonchus s. l cannot be clearly separated, possibly implying that all the genera share a recent common ancestor (Zeng et al, 2007).…”

Molecular and Morphological Characterization of Aphelenchoides fuchsi sp. n. (Nematoda: Aphelenchoididae) Isolated from Pinus eldarica in Western Iran

“…Small subunit of rDNA contains sufficient phylogenetic signal for the identification of Aphelenchoides species (De Ley et al, 2006;Zhao et al, 2008;Van Megen et al, 2009) and have been shown to be more useful for species identification compared to D2-D3 expansion segments of 28S rRNA and internal transcribed spacer rRNA, as both of these markers showed more species variability than did partial 18S rDNA (Zhao et al 2008;Esmaeili et al, 2016). This is the second new species of the genus from Iran to be described and sequenced.…”

Morphological and molecular characterization of Laimaphelenchus deconincki (Nematoda: Aphelenchoididae) based on specimens from Iran

“…In a study of Laimaphelenchus and Aphelenchoides species, Zhao et al (2008) showed that i) L. preissii and Aphelenchoides sp. (EU287599) were a sister group ii) L. heidelbergi and Aphelenchoides sp.…”