title: Phytophthora terminalis sp. nov. and Phytophthora occultans sp. nov., two invasive pathogens of ornamental plants in Europe.
abstract: In the past decade several Phytophthora strains were isolated from diseased Pachysandra terminalis plants suffering stem base and root rot, originating from the Netherlands and Belgium. All isolates were homothallic and had a felt-like colony pattern, produced semi-papillate sporangia, globose oogonia and had a maximum growth at ~ 27 C. Several additional Phytophthora strains were isolated from diseased Buxus sempervirens plants, originating from the Netherlands and Belgium, which had sustained stem base and root rot; similar strains also were isolated from Acer palmatum, Choisya ternata and Taxus in the United Kingdom. All isolates were homothallic and had a stellate colony pattern, produced larger semi-papillate sporangia and smaller globose oogonia than the isolates from Pa. terminalis and had a maximum growth temperature of ~ 30 C. Phylogenetic analyses of both species using the internal transcribed spacer region of the nuc rDNA (ITS), mt cytochrome oxidases subunit I gene (CoxI) and nuc translation elongation factor 1-α gene (TEF1α) revealed that all sequences of each species were identical at each locus and unique to that species, forming two distinct clusters in subclade 2a. Sequence analysis of partial β-tubulin genes showed that both taxa share an identical sequence that is identical to that of Ph. himalsilva, a species originating from Asia, suggesting a common Asian origin. Pathogenicity trials demonstrated disease symptoms on their respective hosts, and re-isolation and re-identification of the inoculated pathogens confirmed Koch's postulates.
authors.affiliation: Plant Protection Service, Ministry of Economic Affairs, P.O. Box 9102, 6700 HC Wageningen, the Netherlands w.a.man.in.t.veld@minlnv.nl.
authors.forename: Willem A
authors.initials: WA
authors.lastname: Man In 't Veld
authors.affiliation: Plant Protection Service, Ministry of Economic Affairs, P.O. Box 9102, 6700 HC Wageningen, the Netherlands.
authors.forename: Karin C H M
authors.initials: KC
authors.lastname: Rosendahl
authors.affiliation: Plant Protection Service, Ministry of Economic Affairs, P.O. Box 9102, 6700 HC Wageningen, the Netherlands.
authors.forename: Patricia C J
authors.initials: PC
authors.lastname: van Rijswick
authors.affiliation: Plant Protection Service, Ministry of Economic Affairs, P.O. Box 9102, 6700 HC Wageningen, the Netherlands.
authors.forename: Johan P
authors.initials: JP
authors.lastname: Meffert
authors.affiliation: Plant Protection Service, Ministry of Economic Affairs, P.O. Box 9102, 6700 HC Wageningen, the Netherlands.
authors.forename: Marcel
authors.initials: M
authors.lastname: Westenberg
authors.affiliation: Plant Protection Service, Ministry of Economic Affairs, P.O. Box 9102, 6700 HC Wageningen, the Netherlands.
authors.forename: Bart T L H
authors.initials: BT
authors.lastname: van de Vossenberg
authors.affiliation: The Royal Horticultural Society, RHS Garden Wisley, Woking, Surrey GU23 6QB, United Kingdom.
authors.forename: Geoff
authors.initials: G
authors.lastname: Denton
authors.affiliation: Praktijkonderzoek Plant en Omgeving, Wageningen UR, P.O. Box 85, 2160 AB Lisse, the Netherlands.
authors.forename: Fons A J
authors.initials: FA
authors.lastname: van Kuik
mesh_terms: D005060:Europe; D008969:Molecular Sequence Data; D010802:Phylogeny; D010838:Phytophthora / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D010935:Plant Diseases / Q000382:microbiology*; D010944:Plants / Q000382:microbiology*; D013172:Spores, Fungal / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification
keywords: Asian radiation; global trade; invasive species; plant pathogens; taxonomy