ARS | Publication request: Molecular phylogenetics and the evolution of host plant associations in the nematode genus Fergusobia (Tylenchida: Fergusobiinae)

Submitted to: Molecular Phylogenetics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 15, 2007
Publication Date: March 12, 2007
Citation: Weimin, Y., Giblin-Davis, R.M., Davies, K.A., Purcell, M.F., Scheffer, S.J., Taylor, G.S., Center, T.D., Morris, K., Thomas, K. 2007. Molecular phylogenetics and the evolution of host plant associations in the nematode genus Fergusobia (Tylenchida: Fergusobiinae). Molecular Phylogenetics and Evolution. 45:123-141.

Technical Abstract: Fergusobia nematodes (Tylenchida: Fergusobiinae) and Fergusonina flies (Diptera: Fergusoninidae) are mutualists that develop together in galls formed in meristematic tissues of many species of the plant family Myrtaceae in Australasia. Evolutionary relationships of Fergusobia species were inferred from phylogenetic analyses of the DNA sequences of the nuclear ribosomal DNA near-full length small subunit (up to1689 bp), partial large subunit D2/D3 domain (up to 889 bp), and partial mitochondrial cytochrome oxidase subunit I (618 bp). The analyses included 21 SSU, 87 D2/D3, 82 mtCOI, and 66 combined D2/D3 and mtCOI sequences from Fergusobia isolates sampled from a variety of myrtaceous hosts and gall types in Australia and New Zealand between 1999 and 2006. The SSU data supported a monophyletic Fergusobia genus within a paraphyletic Howardula. A clade of Drosophila-associated Howardula, including H. aoronymphium, was the closest sequenced sister group. Phylogenetic analysis of sequences from D2/D3 and mtCOI, separately and combined, revealed many monophyletic clades within Fergusobia. The relationships inferred by D2/D3 and mtCOI were congruent with some exceptions. Well-supported clades were generally consistent with host plant species and gall type. However, phylogenetic analysis suggested host switching or putative hybridization events in many groups, except the lineage of shoot bud gallers on the broad-leaved Melaleuca species complex.