title: Disentangling Peronospora on Papaver: phylogenetics, taxonomy, nomenclature and host range of downy mildew of opium poppy (Papaver somniferum) and related species.
abstract: Based on sequence data from ITS rDNA, cox1 and cox2, six Peronospora species are recognised as phylogenetically distinct on various Papaver species. The host ranges of the four already described species P. arborescens, P. argemones, P. cristata and P. meconopsidis are clarified. Based on sequence data and morphology, two new species, P. apula and P. somniferi, are described from Papaver apulum and P. somniferum, respectively. The second Peronospora species parasitizing Papaver somniferum, that was only recently recorded as Peronospora cristata from Tasmania, is shown to represent a distinct taxon, P. meconopsidis, originally described from Meconopsis cambrica. It is shown that P. meconopsidis on Papaver somniferum is also present and widespread in Europe and Asia, but has been overlooked due to confusion with P. somniferi and due to less prominent, localized disease symptoms. Oospores are reported for the first time for P. meconopsidis from Asian collections on Papaver somniferum. Morphological descriptions, illustrations and a key are provided for all described Peronospora species on Papaver. cox1 and cox2 sequence data are confirmed as equally good barcoding loci for reliable Peronospora species identification, whereas ITS rDNA does sometimes not resolve species boundaries. Molecular phylogenetic data reveal high host specificity of Peronospora on Papaver, which has the important phytopathological implication that wild Papaver spp. cannot play any role as primary inoculum source for downy mildew epidemics in cultivated opium poppy crops.
authors.affiliation: Division of Systematic and Evolutionary Botany, Department of Botany and Biodiversity Research, University of Vienna, Wien, Austria; Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU-University of Natural Resources and Life Sciences, Wien, Austria.
authors.forename: Hermann
authors.initials: H
authors.lastname: Voglmayr
authors.affiliation: Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Montes-Borrego
authors.affiliation: Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Córdoba, Spain.
authors.forename: Blanca B
authors.initials: BB
authors.lastname: Landa
mesh_terms: D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D058507:Host Specificity / Q000235:genetics; D009892:Opium; D010207:Papaver / Q000235:genetics* / Q000382:microbiology; D044742:Peronospora / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D009892:Opium