title: The transcriptome of Nacobbus aberrans reveals insights into the evolution of sedentary endoparasitism in plant-parasitic nematodes.
abstract: Within the phylum Nematoda, plant-parasitism is hypothesized to have arisen independently on at least four occasions. The most economically damaging plant-parasitic nematode species, and consequently the most widely studied, are those that feed as they migrate destructively through host roots causing necrotic lesions (migratory endoparasites) and those that modify host root tissue to create a nutrient sink from which they feed (sedentary endoparasites). The false root-knot nematode Nacobbus aberrans is the only known species to have both migratory endoparasitic and sedentary endoparasitic stages within its life cycle. Moreover, its sedentary stage appears to have characteristics of both the root-knot and the cyst nematodes. We present the first large-scale genetic resource of any false-root knot nematode species. We use RNAseq to describe relative abundance changes in all expressed genes across the life cycle to provide interesting insights into the biology of this nematode as it transitions between modes of parasitism. A multigene phylogenetic analysis of N. aberrans with respect to plant-parasitic nematodes of all groups confirms its proximity to both cyst and root-knot nematodes. We present a transcriptome-wide analysis of both lateral gene transfer events and the effector complement. Comparing parasitism genes of typical root-knot and cyst nematodes to those of N. aberrans has revealed interesting similarities. Importantly, genes that were believed to be either cyst nematode, or root-knot nematode, "specific" have both been identified in N. aberrans. Our results provide insights into the characteristics of a common ancestor and the evolution of sedentary endoparasitism of plants by nematodes.
authors.affiliation: Centre for Plant Sciences, University of Leeds, United Kingdom Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Dundee, United Kingdom.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Eves-van den Akker
authors.affiliation: Centre for Plant Sciences, University of Leeds, United Kingdom.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Lilley
authors.affiliation: Centre National de la Recherche Scientifique, INRA Institut National de la Recherche Agronomique, UMR 1355, Université de Nice-Sophia Antipolis, Sophia-Antipolis, France.
authors.forename: Etienne G J
authors.initials: EG
authors.lastname: Danchin
authors.affiliation: Centre National de la Recherche Scientifique, INRA Institut National de la Recherche Agronomique, UMR 1355, Université de Nice-Sophia Antipolis, Sophia-Antipolis, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Rancurel
authors.affiliation: Information and Computational Sciences Group, Dundee Effector Consortium, James Hutton Institute, Dundee, United Kingdom.
authors.forename: Peter J A
authors.initials: PJ
authors.lastname: Cock
authors.affiliation: Centre for Plant Sciences, University of Leeds, United Kingdom p.e.urwin@leeds.ac.uk john.jones@hutton.ac.uk.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Urwin
authors.affiliation: Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Dundee, United Kingdom p.e.urwin@leeds.ac.uk john.jones@hutton.ac.uk.
authors.forename: John T
authors.initials: JT
authors.lastname: Jones
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D015801:Helminth Proteins / Q000235:genetics* / Q000378:metabolism; D058507:Host Specificity; D006790:Host-Parasite Interactions; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000469:parasitology*; D016415:Sequence Alignment; D014026:Nicotiana / Q000469:parasitology; D059467:Transcriptome; D014431:Tylenchoidea / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
chemical_list: D015801:Helminth Proteins
keywords: RNAseq; effectors; host mimics; lateral gene transfer; phylogenetics; plant-parasitic nematode