Identification, phylogeny and phylogeography of circumfenestrate cyst nematodes (Nematoda: Heteroderidae) as inferred from analysis of ITS-rDNA

Some 134 ITS rRNA gene sequences for circumfenestrate cyst nematodes and two sequences for non-cyst nematodes of the family Heteroderidae, of which 46 were newly obtained, were analysed by phylogenetic and phylogeographic methods. Sequence and phylogenetic analysis combined with known morphological, biological and geographical data allowed the identification, amongst samples original to this study, of several belonging to known valid species as well as others that might be new species. The phylogenetic analysis revealed six major clades for circumfenestrate cyst nematodes: i) Globodera from South and North America; ii) Globodera from Europe, Asia, Africa and Oceania; iii) Paradolichodera; iv) Punctodera; v) Cactodera; and vi) Betulodera. Monophylies of Punctodera, Cactodera and Betulodera were highly supported. The Betulodera clade occupied a basal position on all trees. Phylogeographic analysis suggested a North American origin of Punctoderinae with possible further long distance dispersal to South America, Africa and other regions. Molecular data supported synonymisation of G. achilleae with G. millefolii and of G. hypolysi with G. artemisiae. PCR-RFLP diagnostic profiles for some Globodera and Cactodera species are given. Problems of diagnostics for Globodera species using PCR with specific primers are discussed.