@article {4083, title = {First report of bleeding canker caused by Phytophthora cactorum on horse chestnut in Turkey}, journal = {Plant Disease}, volume = {86}, year = {2002}, month = {06/2002}, pages = {697 - 697}, abstract = {

Bleeding canker on horse chestnut (Aesculus sp.), caused by Phytophthora cactorum (Lebert and Cohn) Schr{\"o}eter previously has been reported from the United States and Europe (1). In August 2000, it was found for the first time in a park in Ankara Province, Turkey. Symptoms included sparse yellowish brown foliage with abnormally small leaves, and dark-stained spots or dark brown necrosis of the bark on the trunk and main branches, with or without a reddish black gummy exudate. P. cactorum was isolated from tissues taken from the margins of necrotic bark. Pure cultures were slightly radiate, fluffy but not dense, and had short aerial hyphae when grown on carrot agar, potato dextrose agar, or V8 agar. Sporangia were ovoid, strongly papillate, and averaged 35.6 μm in length and 26.8 μm in width (range: 24 to 55 μm {\texttimes} 19 to 40 μm). The isolates were homothallic with smooth-walled paragynous oogonia ranging from 23.5 to 34.5 μm in diameter. To satisfy Koch{\textquoteright}s postulates, mycelium of P. cactorum was placed under the bark of six branches of healthy horse chestnut. Noninoculated wounds served as controls. Four months later a reddish black gummy exudate was observed oozing from the inoculated wounds, and the bark tissue was necrotic for 3 to 4 cm around each infection. P. cactorum was successfully reisolated from the necrotic bark tissue. Control wounds remained healthy. To our knowledge, this is the first report of this disease on horse chestnut in Asia Minor.

}, issn = {0191-2917}, doi = {10.1094/PDIS.2002.86.6.697C}, url = {http://dx.doi.org/10.1094/PDIS.2002.86.6.697C}, author = {Intini, M. and Gurer, M. and Ozturk, S.} } @article {Ioos2006511, title = {Genetic characterization of the natural hybrid species Phytophthora alni as inferred from nuclear and mitochondrial DNA analyses}, journal = {Fungal Genetics and Biology}, volume = {43}, number = {7}, year = {2006}, pages = {511 - 529}, abstract = {

The different subspecies of Phytophthora alni, P. alni subsp. alni (Paa), P. alni subsp. uniformis (Pau), and P. alni subsp. multiformis (Pam), are recent and widespread pathogens of alder in Europe. They are believed to be a group of emergent heteroploid hybrids between two phylogenetically close Phytophthora species. Nuclear and mitochondrial DNA analyses were performed, using a broad collection of P. alni and two closely related species, P. cambivora and P. fragariae. (Paa) possesses three different alleles for each of the nuclear genes we studied, two of which are present in Pam as well, whereas the third matches the single allele present in Pau. Moreover, Paa displays common mtDNA patterns with both Pam and Pau. A combination of the data suggests that Paa may have been generated on several occasions by hybridization between Pam and Pau, or their respective ancestors. Pau might have P. cambivora as a species ancestor, whereas Pam seems to have either been generated itself by an ancient reticulation or by autopolyploidization.

}, keywords = {Interspecific hybridization}, issn = {1087-1845}, doi = {DOI: 10.1016/j.fgb.2006.02.006}, url = {http://www.sciencedirect.com/science/article/B6WFV-4JS1TK3-1/2/aead0efc6dc22a393ebadec5b3211855}, author = {Renaud Ioos and Axelle Andrieux and Beno{\'O}t Mar{\'A}ais and Pascal Frey} } @article {MEN:MEN1554, title = {Characterization of microsatellite markers in the interspecific hybrid Phytophthora alni ssp. alni, and cross-amplification with related taxa}, journal = {Molecular Ecology Notes}, volume = {7}, number = {1}, year = {2007}, pages = {133{\textendash}137}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora alni ssp. alni is an interspecific hybrid oomycete causing a large-scale decay of alders throughout Europe. In this study we developed a set of 10 microsatellite markers that shows promise for population studies and for studying hybridization events between the parental species of the hybrid. Moreover, the genotype and the ploidy of the different subspecies of P. alni might be inferred from the quantitative ratio of amplified genome-specific alleles. Nine primer pairs cross amplified with the related species Phytophthora cambivora and Phytophthora fragariae and yielded distinct alleles.

}, keywords = {genotyping, oomycete, polyploidy}, issn = {1471-8286}, doi = {10.1111/j.1471-8286.2006.01554.x}, url = {http://dx.doi.org/10.1111/j.1471-8286.2006.01554.x}, author = {Renaud Ioos and Barr{\'e}s, Beno{\^{\i}t and Axelle Andrieux and Pascal Frey} } @article {springerlink:10.1007/s10658-005-6233-2, title = {SCAR{\textendash}based PCR primers to detect the hybrid pathogen Phytophthora alni and its subspecies causing alder disease in Europe}, journal = {European Journal of Plant Pathology}, volume = {112}, year = {2005}, note = {10.1007/s10658-005-6233-2}, pages = {323-335}, publisher = {Springer Netherlands}, abstract = {

Since the 1990s, a new Phytophthora species hybrid has been jeopardizing the natural population of alders throughout Europe. This new Phytophthora, P. alni, has been suggested as a natural hybrid between two closely related species of Phytophthora. Little is known about the epidemiology of this pathogen, because its direct isolation is not always satisfactory. In this study we developed three pairs of Polymerase Chain Reaction (PCR) primers derived from Sequence Characterized Amplified Regions (SCAR) that allow discrimination among the three subspecies of P. alni: P. alni subsp. alni, P. alni subsp. uniformis and P. alni subsp. multiformis. These molecular tools were successfully used to detect P. alni directly in different substrates such as infested river water and soil, and necrotic alder bark, without the need for any prior baiting or isolation stages. An Internal Amplification Control (IAC) was included to help discriminate against false negative samples due to the potential presence of inhibitory compounds in DNA extracts. These molecular tools should be useful for epidemiological studies on this emerging disease.

}, issn = {0929-1873}, url = {http://dx.doi.org/10.1007/s10658-005-6233-2}, author = {Renaud Ioos and Husson, Claude and Axelle Andrieux and Pascal Frey} } @article {1227, title = {Distribution and expression of elicitin genes in the interspecific hybrid oomycete Phytophthora alni}, journal = {Appl. Environ. Microbiol.}, volume = {73}, year = {2007}, pages = {5587-5597}, abstract = {

Phytophthora alni subsp. alni, P. alni subsp. multiformis, and P. alni subsp. uniformis are responsible for alder disease in Europe. Class I and II elicitin gene patterns of P. alni subsp. alni, P. alni subsp. multiformis, P. alni subsp. uniformis, and the phylogenetically close species P. cambivora and P. fragariae were studied through mRNA sequencing and 3{\textquoteright} untranslated region (3{\textquoteright}UTR)-specific PCRs and sequencing. The occurrence of multiple 3{\textquoteright}UTR sequences in association with identical elicitin-encoding sequences in P. alni subsp. alni indicated duplication/recombination events. The mRNA pattern displayed by P. alni subsp. alni demonstrated that elicitin genes from all the parental genomes are actually expressed in this allopolyploid taxon. The complementary elicitin patterns resolved confirmed the possible involvement of P. alni subsp. multiformis and P. alni subsp. uniformis in the genesis of the hybrid species P. alni subsp. alni. The occurrence of multiple and common elicitin gene sequences throughout P. cambivora, P. fragariae, and P. alni sensu lato, not observed in other Phytophthora species, suggests that duplication of these genes occurred before the radiation of these species.

}, doi = {doi:10.1128/AEM.00721-07}, url = {http://aem.asm.org/content/73/17/5587.abstract}, author = {Renaud Ioos and Panabi{\`e}res, Franck and Industri, Beno{\^{\i}t and Axelle Andrieux and Pascal Frey} } @article {PPA:PPA2513, title = {Potential susceptibility of Australian native plant species to branch dieback and bole canker diseases caused by Phytophthora ramorum}, journal = {Plant Pathology}, volume = {61}, number = {2}, year = {2012}, pages = {234{\textendash}246}, publisher = {Blackwell Publishing Ltd}, abstract = {

Susceptibility to branch dieback caused by Phytophthora ramorum was tested using a detached branch assay for 66 Australian native plant species sourced from established gardens and arboreta in California. Six of these species were further tested for their susceptibility to bole cankers caused by P.\ ramorum using a sealed log assay. Isopogon formosus and Eucalyptus denticulata were identified as potentially highly susceptible Australian branch dieback hosts. Thirteen potentially tolerant Australian host species included Banksia attenuata, B.\ marginata, E. haemastoma, E.\ regnans, Pittosporum undulatum and Billardiera heterophylla. Eucalyptus regnans was identified as a potentially highly susceptible bole canker host, while E.\ diversicolor and E.\ viminalis were considered potentially tolerant species to bole cankers caused by P.\ ramorum. Phytophthora ramorum was able to infect all 66 species, as confirmed by reisolation. These results extend the known potential host range for P.\ ramorum, confirm it as a possible threat to Australian plant industries and ecosystems and highlight additional associated hosts that are important in the global horticultural trade, native forests and plantation forestry.

}, keywords = {invasive organism, oomycete, ramorum branch dieback, Sudden oak death}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02513.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02513.x}, author = {Ireland, K. B. and H{\"u}berli, D. and Dell, B. and Smith, I. W. and D. M. Rizzo and Hardy, G. E. St. J.} } @article {EFP:EFP755, title = {Potential susceptibility of Australian flora to a NA2 isolate of Phytophthora ramorum and pathogen sporulation potential}, journal = {Forest Pathology}, volume = {42}, year = {2011}, pages = {305{\textendash}320}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum is an invasive plant pathogen and the cause of considerable and widespread damage in nurseries, gardens and natural woodland ecosystems of the USA and Europe. It is considered to be a significant plant disease as it could cause biodiversity loss and severe economic losses in plant industries in areas where it is not yet known to exist, such as Australasia. Foliar susceptibility and sporulation potential were tested using detached-leaf assays for 70 Australian native plant species sourced from established gardens and arboreta in California using a NA2 isolate of P. ramorum. Correa {\textquoteright}Sister Dawn{\textquoteright}, Eucalyptus regnans, Isopogon cuneatus, I. formosus, Leptospermum scoparium, L. lanigerum and Melaleuca squamea were identified as potentially highly susceptible host species. Hedycarya angustifolia, Olearia argophylla, Phyllocladus aspleniifolius, Pittosporum undulatum and Podocarpus lawrencei were identified as potentially resistant. All 70 species were able to be infected with P. ramorum, as confirmed by reisolation. Putative sporulating hosts include five members of the Myrtaceae, Agonis flexuosa, Corymbia ficifolia, Eucalyptus haemastoma, E. delegatensis and E. viminalis. As a part of a precautionary strategy, the potentially highly susceptible species found in this study are suitable candidates for targeted surveillance programmes in high-risk incursion areas of Australia and within the global horticultural trade.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00755.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00755.x}, author = {Ireland, K. B. and H{\"u}berli, D. and Dell, B. and Smith, I. W. and D. M. Rizzo and Hardy, G. E. St. J.} } @article {Ivors2004378, title = {AFLP and phylogenetic analyses of North American and European populations of Phytophthora ramorum}, journal = {Mycological Research}, volume = {108}, number = {4}, year = {2004}, pages = {378 - 392}, abstract = {

The genetic structure within and between USA and European populations of the emerging phytopathogen Phytophthora ramorum was examined. Four primer combinations were used for amplified fragment length polymorphism (AFLP) fingerprinting of 67 USA isolates from California and Oregon, and 18 European isolates from Belgium, Germany, The Netherlands, Spain and the UK. In addition, three DNA regions (ITS, cox II, and nad 5) of additional Phytophthora species were amplified by polymerase chain reaction, sequenced, and analysed to provide better phylogenetic understanding of P. ramorum within the genus Phytophthora. AFLP banding patterns indicate that the 85 isolates form two distinct lineages within a monophyletic group, distinct from the closely related outgroup species P. lateralis. With the exception of two isolates from an Oregon nursery, European and USA isolates clustered separately within individual clades. The AFLP profiles also indicate that a single clonal lineage dominates the North American population, while the European population consists of an array of mainly unique, closely related AFLP types. Sequences from the three DNA regions were identical among all P. ramorum isolates, and phylogenetic analysis indicates that P. ramorum is closely related to P. lateralis and P. hibernalis.

}, issn = {0953-7562}, doi = {10.1017/S0953756204009827}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208615609}, author = {Ivors, Kelly L. and Katherine J. Hayden and Peter J.M. Bonants and Rizzo, David M. and Garbelotto, Matteo} } @article {MEC:MEC2864, title = {Microsatellite markers identify three lineages of Phytophthora ramorum in US nurseries, yet single lineages in US forest and European nursery populations}, journal = {Molecular Ecology}, volume = {15}, number = {6}, year = {2006}, pages = {1493{\textendash}1505}, publisher = {Blackwell Publishing Ltd}, abstract = {

Analysis of 12 polymorphic simple sequence repeats identified in the genome sequence of Phytophthora ramorum, causal agent of {\textquoteleft}sudden oak death{\textquoteright}, revealed genotypic diversity to be significantly higher in nurseries (91\% of total) than in forests (18\% of total). Our analysis identified only two closely related genotypes in US forests, while the genetic structure of populations from European nurseries was of intermediate complexity, including multiple, closely related genotypes. Multilocus analysis determined populations in US forests reproduce clonally and are likely descendants of a single introduced individual. The 151 isolates analysed clustered in three clades. US forest and European nursery isolates clustered into two distinct clades, while one isolate from a US nursery belonged to a third novel clade. The combined microsatellite, sequencing and morphological analyses suggest the three clades represent distinct evolutionary lineages. All three clades were identified in some US nurseries, emphasizing the role of commercial plant trade in the movement of this pathogen.

}, keywords = {exotic microbe, oomycete, population genetics, SSR, Sudden oak death}, issn = {1365-294X}, doi = {10.1111/j.1365-294X.2006.02864.x}, url = {http://dx.doi.org/10.1111/j.1365-294X.2006.02864.x}, author = {K. Ivors and Garbelotto, M. and Vries, I. D. E. and Ruyter-Spira, C. and Hekkert, B. TE. and Rosenzweig, N. and Bonants, P.} }