Multigene phylogeny of root-knot nematodes and molecular characterization of Meloidogyne nataliei Golden, Rose & Bird, 1981 (Nematoda: Tylenchida)

Abstract

The root-knot nematodes of the genus Meloidogyne are highly adapted, obligate plant parasites, consisting of nearly one hundred valid species, and are considered the most economically important group of plant-parasitic nematodes. Six Meloidogyne species: M . arenaria , M . hapla , M . incognita , M . microtyla , M . naasi and M . nataliei were previously reported in Michigan, USA. For this study, Meloidogyne nataliei was isolated from the grapevine Vitis labrusca from the type locality in Michigan, USA, and was characterized using isozyme analysis and ribosomal and mitochondrial gene sequences. No malate dehydrogenase activity was detected using macerate of one, five, six, seven or ten females of M . nataliei per well. However, one strong band (EST = S1; Rm: 27.4) of esterase activity was detected when using homogenates of ten egg-laying females per well. Phylogenetic analyses of sequences of the partial 18S ribosomal RNA, D2-D3 of 28S rRNA, internal transcribed spacer of rRNA, mitochondrial cytochrome oxidase subunit I genes and the cytochrome oxidase subunit II -16S rRNA intergeneric fragment from fifty-five valid Meloidogyne species and M . nataliei were conducted using Bayesian inference and maximum likelihood methods. From these results, we infer 11 distinct clades among studied species, with M . nataliei and M . indica composing a basal lineage. Seventy five percent of these species belong to seven clades within the Meloidogyne superclade. Characterization of these clades is provided and evolutionary trends within the root-knot nematodes are discussed.

A Single, Shared Triploidy in Three Species of Parasitic Nematodes

“…These results lead us to conclude that these three MIG genomes descend from a single, common hybridization event. Curiously, the maximum likelihood topology inferred with POInT for these three organisms differs from both of the published ones (Tigano et al 2005;Brito et al 2015;Szitenberg et al 2017;Álvarez-Ortega et al 2019): we speculate that it may be difficult to infer phylogenetic relationships among these species with standard gene tree approaches due to the paralogy introduced by the triploidy.…”

“…These nematodes' adaptability is illustrated by their rapid invasions of numerous crop species in the few thousand years since the origins of agriculture (Lunt et al 2014). As suggested by the cartoon phylogeny in Figure 1A, the relationships of these three MIG species are still contested, with some published studies proposing that M. arenaria and M. javanica are sister to each other (Tigano et al 2005;Szitenberg et al 2017) and others arguing for M. incognita and M. arenaria as sisters (Brito et al 2015;Álvarez-Ortega et al 2019).…”

“…A) A schematic phylogeny of the root-knot nematodes showing the placement of the hybridization event shared by the MIG group. The tree topology was adapted from published phylogenetic inferences (Tigano et al 2005;Brito et al 2015;Szitenberg et al 2017;Álvarez-Ortega et al 2019). B) Of the three possible rooted topologies for the three MIG taxa, we show the one that gives the maximum likelihood of observing the set of gene losses found in these genomes (Methods).…”

Sensitive, Accurate and Rapid Detection of the Northern Root-Knot Nematode, Meloidogyne hapla, Using Recombinase Polymerase Amplification Assays

“…Accurate and rapid identification of nematodes is essential for their control. It has been shown that sequences of nuclear ribosomal genes: 18S rRNA, ITS rRNA, the D2-D3 of 28S rRNA, IGS rRNA and mitochondrial genes: COII-16S rRNA fragment, COI and COII clearly differentiate M. hapla from all other root-knot nematodes [3]. Several specific primers have been designed for the diagnostics of this species using conventional PCR [4][5][6][7].…”

First report of Meloidogyne hapla on kiwifruit in South Africa

“…The molecular characterization followed the methods described in Álvarez-Ortega et al (2019) . The ribosomal ITS and LSU sequences were analyzed and aligned using the program BioEdit ( Hall, 1999 ), aligned using CLUSTAL W ( Thompson et al, 1994 ).…”