Academic literature on the topic 'Phytophthora alni'
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Journal articles on the topic "Phytophthora alni"
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Pintos Varela, C., C. Rial Martínez, J. P. Mansilla Vázquez, and O. Aguín Casal. "First Report of Phytophthora Rot on Alders Caused by Phytophthora alni subsp. alni in Spain." Plant Disease 94, no. 2 (February 2010): 273. http://dx.doi.org/10.1094/pdis-94-2-0273a.
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Phytophthora alni, a soil- and waterborne pathogen, causes aggressive root and collar rot on riparian alder populations (1,2,4). The disease has been described from several European countries with a destructive impact in Great Britain (1,2). All European alder species and the red alder (Alnus rubra) are highly susceptible. P. alni has multiple variants that have been placed in three subspecies: P. alni subsp. alni, P. alni subsp. uniformis, and P. alni subsp. multiformis (1). In July 2009, a survey of symptoms of Phytophthora rot from A. glutinosa at 20 riparian stands along the Avia River in Galicia (northwest Spain) was conducted. Affected trees showed symptoms of Phytophthora rot including abnormally small, sparse, and yellowish foliage, dieback in the canopy, necroses of the inner bark and cambium, and bleeding cankers on the trunks (2,4). Phytophthora spp. were baited from saturated rhizosphere soil and watercourses using oak leaflets (4). Roots and tissue from fresh active inner bark lesions were transferred to selective medium V8-PARPH agar (4) and incubated for 7 days at 22°C in the dark. A Phytophthora sp. was isolated, transferred to carrot agar (CA), and incubated in the dark. Colonies were appressed, often irregular in outline, and with limited aerial mycelium (1). Growth on CA occurred from 4 to 31°C with optimum growth at 23 to 25°C. Chlamydospores were not observed. Ellipsoid, nonpapillate, noncaducous sporangia had a length/breadth average ratio of 1.4. Nesting and extended internal proliferation occurred. Oogonia, antheridia, and oospores were abundantly produced in a single culture. Oogonia with tapered stalks were spherical (mature oogonia 38 to 50 μm in diameter) and some had ornamented walls or bullate protuberances (1,2). Antheridia were large, amphigynous, and predominantly two-celled (23 to 37 × 16 to 23 μm). Oospores were plerotic. Distorted comma-shaped or smaller oogonia and aborted oospores were observed (1). Amplification of DNA was accomplished by using sequence-characterized amplification region-PCR primers (3). The amplicon sizes obtained were identical to P. alni subsp. alni (3). Internal transcribed spacer (ITS)-DNA and nadh1 mitochondrial gene were also amplified. DNA sequences of ITS and mt-DNA regions were deposited in GenBank (Nos. GU108602 and GU108603). Comparison of the sequences showed 100% homology with P. alni subsp. alni (GenBank Nos. FJ746679 and DQ202490). P. alni subsp. alni was recovered from trees at 3 of 20 riparian alder stands with symptoms. Pathogenicity of one representative isolate was confirmed by inoculating 10 3-year-old A. glutinosa seedlings grown in pots. One shallow cut was made into the bark at the collar level. A colonized agar plug, from the margin of an actively growing colony of P. alni subsp. alni, was inserted beneath the flap that was sealed with Parafilm. Five controls seedlings received only sterile CA agar plugs. Plants were incubated at 24°C and 95% humidity for 30 days. On inoculated plants, necroses progressed bidirectionally from the wound, and dead leaves and wilting of shoots were observed. P. alni subsp. alni was recovered from inoculated seedlings, but not from controls. To our knowledge, this is the first report of Phytophthora rot on alder caused by P. alni subsp. alni in Spain. References: (1) C. M. Brasier et al. Mycol. Res. 108:1172, 2004. (2) J. Gibbs et al. For. Comm. Bull. 126, 2003 (3) R. Ioos et al. Eur. J. Plant Pathol. 112:323, 2005. (4) T. Jung et al. Plant Pathol. 53:197, 2004.
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Štěpánková, P., K. Černý, V. Strnadová, P. Hanáček, and M. Tomšovský. "Identification of Phytophthora alni subspecies in riparian stands in the Czech Republic." Plant Protection Science 49, Special Issue (November 19, 2013): S3—S10. http://dx.doi.org/10.17221/41/2013-pps.
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In the Czech Republic, Phytophthora alni was first confirmed in 2001 and the pathogen has been quickly spreading and occupying almost the whole area of the country. The pathogen attacks Alnus glutinosa or A. incana to a lesser extent and causes considerable losses of alder trees along hundreds of kilometres of riverbanks. The aim of our work was to perform the identification of P. alni isolates at the subspecific level using PCR and to determine the frequencies and distribution of particular subspecies. The allele-specific PCR primers focused on allele diversity of orthologs of ASF-like, TRP1, RAS-Ypt, and GPA1 genes were selected for identification. Eighty-eight per cent of the 59 analysed isolates belonged to P. alni ssp. alni while 12% were P. alni ssp. uniformis. P. alni ssp. multiformis has not been recorded in the country till now. The two subspecies differed in distribution. P. alni ssp. alni dominated in riparian stands along broader rivers in lowlands and the results confirmed the more effective spreading of P. alni ssp. alni based on its higher aggressiveness and ecological advantage. P. alni ssp. uniformis was acquired rather from riparian stands of small watercourses at higher altitudes. The insular distribution of P. alni ssp. uniformis may represent the remains of its former occurrence. Therefore, P. alni ssp. uniformis may be an indigenous subspecies suppressed by the more aggressive related taxon.
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Ioos, Renaud, Franck Panabières, Benoît Industri, Axelle Andrieux, and Pascal Frey. "Distribution and Expression of Elicitin Genes in the Interspecific Hybrid Oomycete Phytophthora alni." Applied and Environmental Microbiology 73, no. 17 (June 29, 2007): 5587–97. http://dx.doi.org/10.1128/aem.00721-07.
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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′ untranslated region (3′UTR)-specific PCRs and sequencing. The occurrence of multiple 3′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.
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Redondo, Miguel A., Johanna Boberg, Christer H. B. Olsson, and Jonàs Oliva. "Winter Conditions Correlate with Phytophthora alni Subspecies Distribution in Southern Sweden." Phytopathology® 105, no. 9 (September 2015): 1191–97. http://dx.doi.org/10.1094/phyto-01-15-0020-r.
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During the last century, the number of forest pathogen invasions has increased substantially. Environmental variables can play a crucial role in determining the establishment of invasive species. The objective of the present work was to determine the correlation between winter climatic conditions and distribution of two subspecies of the invasive forest pathogen Phytophthora alni: P. alni subspp. alni and uniformis killing black alder (Alnus glutinosa) in southern Sweden. It is known from laboratory experiments that P. alni subsp. alni is more pathogenic than P. alni subsp. uniformis, and that P. alni subsp. alni is sensitive to low temperatures and long frost periods. By studying the distribution of these two subspecies at the northern limit of the host species, we could investigate whether winter conditions can affect the geographical distribution of P. alni subsp. alni spreading northward. Sixteen major river systems of southern Sweden were systematically surveyed and isolations were performed from active cankers. The distribution of the two studied subspecies was highly correlated with winter temperature and duration of periods with heavy frost. While P. alni subsp. uniformis covered the whole range of temperatures of the host, P. alni subsp. alni was recovered in areas subjected to milder winter temperatures and shorter frost periods. Our observations suggest that winter conditions can play an important role in limiting P. alni subsp. alni establishment in cold locations, thus affecting the distribution of the different subspecies of P. alni in boreal regions.
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Nave, Corina, Juliette Schwan, Sabine Werres, and Janett Riebesehl. "Alnus glutinosa Threatened by Alder Phytophthora: A Histological Study of Roots." Pathogens 10, no. 8 (August 3, 2021): 977. http://dx.doi.org/10.3390/pathogens10080977.
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Alder dieback remains a major problem in European alder stands and its spread continues to threaten their existence. The causal agent of this disease is the so-called alder Phytophthora species complex, which includes the hybrid Phytophthora ×alni and its parental species P. uniformis and P. ×multiformis. Little is known about the survival of these Phytophthora species in alder. The aim of our investigations was to find out whether, and if so where, the pathogen survives. The subject of these studies was alder roots. Therefore, artificial infection studies and histological studies with P. ×alni and P. uniformis were carried out on seedlings of black alder (Alnus glutinosa). These histological studies revealed oogonia and oospores of P. ×alni and P. uniformis in different parts of the root tissue.
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Aguayo, Jaime, Gerard C. Adams, Fabien Halkett, Mursel Catal, Claude Husson, Zoltán Á. Nagy, Everett M. Hansen, Benoît Marçais, and Pascal Frey. "Strong Genetic Differentiation Between North American and European Populations of Phytophthora alni subsp. uniformis." Phytopathology® 103, no. 2 (February 2013): 190–99. http://dx.doi.org/10.1094/phyto-05-12-0116-r.
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Alder decline caused by Phytophthora alni has been one of the most important diseases of natural ecosystems in Europe during the last 20 years. The emergence of P. alni subsp. alni —the pathogen responsible for the epidemic—is linked to an interspecific hybridization event between two parental species: P. alni subsp. multiformis and P. alni subsp. uniformis. One of the parental species, P. alni subsp. uniformis, has been isolated in several European countries and, recently, in North America. The objective of this work was to assess the level of genetic diversity, the population genetic structure, and the putative reproduction mode and mating system of P. alni subsp. uniformis. Five new polymorphic microsatellite markers were used to contrast both geographical populations. The study comprised 71 isolates of P. alni subsp. uniformis collected from eight European countries and 10 locations in North America. Our results revealed strong differences between continental populations (Fst = 0.88; Rst = 0.74), with no evidence for gene flow. European isolates showed extremely low genetic diversity compared with the North American collection. Selfing appears to be the predominant mating system in both continental collections. The results suggest that the European P. alni subsp. uniformis population is most likely alien and derives from the introduction of a few individuals, whereas the North American population probably is an indigenous population.
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Varela, C. Pintos, C. Rial Martínez, O. Aguín Casal, J. P. Mansilla Vázquez, and A. Ares Yebra. "First Report of Phytophthora alni subsp. uniformis on Black Alder in Spain." Plant Disease 96, no. 4 (April 2012): 589. http://dx.doi.org/10.1094/pdis-10-11-0891-pdn.
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Phytophthora alni is the causal organism responsible for devastating losses occurring on riparian alders stands in Europe. This emergent hybrid pathogen has multiple variants that have been placed in three subspecies (1). P. alni subsp. uniformis and P. alni subsp. multiformis are reported to be less aggressive than P. alni subsp. alni, though all are considered pathogenic. In Spain, P. alni subsp. alni was detected for the first time in 2009 in Galicia (northwestern Spain) causing root and collar rot on riparian alder populations (3,4), but other subspecies had not been identified. In April 2011, a survey along the Deza River in Galicia was carried out to clarify the Phytophthora sp. associated with the alder decline. Thirty riparian Alnus glutinosa stands, from both sides of the river, were surveyed. Samples of bark and roots of 18 alder stands that showed symptoms of Phytophthora rot and soil from all 30 stands were collected. Roots and tissue from fresh, active, inner bark lesions from 54 trees were transferred to selective medium V8-PARPH agar and incubated for 7 days at 22°C in the dark. P. alni subsp. alni (1) was isolated from roots, bark, or soil in five alder stands. Another Phytophthora sp. was isolated from the bark of one symptomatic tree located in Silleda (Pontevedra), transferred to carrot agar (CA), and incubated in the dark. On CA, the isolate produced irregular and appressed colonies with an optimum growth temperature of 22 to 23°C. The isolate was homothallic with smooth-walled oogonia with a diameter ranging from 36 to 50 μm and two-celled, amphigynous antheridia (1). In soil extract, noncaducous, nonpapillate, ellipsoid-to-ovoid sporangia were produced. Average sporangium were 43.4 × 30.1 μm with a length/breadth ratio of 1.43. Internal proliferation occurred. Amplification of DNA was accomplished by sequence characterized amplified region (SCAR)-PCR primers (2). The amplicon sizes obtained were identical to P. alni subsp. uniformis. Internal transcribed spacer (ITS) (DC6-ITS6/ITS4) and nadh1 (NADHF1/NADHR1) mitochondrial gene regions were also amplified and deposited in GenBank (Nos. JN880411 and JN880410). Comparison of the sequences showed 100% homology with P. alni subsp. uniformis (GenBank Nos. GU259293 and DQ202489). Pathogenicity was tested on 10 3-year-old black alder plants grown in pots. A shallow wound was made with a scalpel at the root collar level of each plant. A 5-mm-diameter mycelia plug, taken from the margin of a 7-day-old culture grown on CA, was inserted in every wound and sealed with Parafilm. Five black alder control plants received only sterile CA agar plugs. Plants were kept at 24°C and 80% humidity. After 3 months, wilting of shoots, dead leaves, and dark stained necroses of the bark tissue varying in length from 0.8 to 5 cm were observed on inoculated plants. Control plants remained healthy. P. alni subsp. uniformis was recovered from inoculated plants, but not from controls. To our knowledge, this is the first time that P. alni subsp. uniformis has been reported in Spain. The presence of a new subspecies in a new region can result in hybridization between individuals of different species or subspecies. This process may allow the rapid evolution and adaptation of these species to new hosts or environmental conditions. References: (1) C. M. Brasier et al. Mycol. Res. 108:1172, 2004. (2) R. Ioos et al. Eur. J. Plant Pathol. 112:323, 2005. (3) C. Pintos et al. Plant Dis. 94:273, 2010. (4) A. Solla et al. Plant Pathol.59:78, 2010.
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Strnadová, V., K. Černý, V. Holub, and B. Gregorová. "The effects of flooding and Phytophthora alni infection on black alder." Journal of Forest Science 56, No. 1 (January 28, 2010): 41–46. http://dx.doi.org/10.17221/67/2009-jfs.
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The influences of long-term flooding and <I>Phytophthora alni</I> subsp. <I>alni</I> infection on the growth and development of 4-year-old <I>Alnus glutinosa</I> (black alder) saplings were investigated. The black alder saplings were divided into four groups and then subjected to combinations of both factors – flooded and inoculated with pathogen, flooded non-inoculated, non-flooded inoculated, and control. The biomass of the living roots and actinorrhizae, increase in stem length, length of leaves, rate of chlorotic foliage, amount of foliage biomass and length of stem necrosis were assessed after seven weeks. Both factors, flooding and <I>P. alni</I> infection significantly affected the black alder. In addition, a significant effect of interaction was observed. The inoculated flooded group had a substantially lower biomass weight of living roots, actinorrhiza and leaves than the other groups. The necroses caused by the pathogen in the flooded group were more extensive than those in the non-flooded one. These findings demonstrate that the simultaneous incidence of stress caused by flooding and <I>P. alni</I> infection is highly dangerous for black alder.
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Štochlová, P., K. Novotná, and K. Černý. " Factors affecting the development of Phytophthora alni ssp. alni infections in Alnus glutinosa L." Journal of Forest Science 58, No. 3 (March 27, 2012): 123–30. http://dx.doi.org/10.17221/26/2011-jfs.
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Phytophthora alni is responsible for a devastating disease in alder and changes in the environment of riparian and alder carr ecosystems. One of the main approaches to solve this problem is to find naturally resistant genotypes using a series of artificial inoculation experiments, to preserve and use them in programmes for resistance breeding. However, the results of artificial inoculation experiments (screening for natural resistance) can be affected by several factors. The potential effect of the social status of the host, the presence of naturally occurring P. alni infections, the season and the size of the sections of branches used were studied in a series of infection experiments. It was found out that the development of lesions was significantly affected by the year season (the largest lesions were found in summer) and by the presence of naturally occurring P. alni infections in the sampled trees (the lesions were five times larger in healthy trees and trees recovered from natural P. alni infections compared to trees with active disease development).
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Sárándi-Kovács, Judit, Ferenc Lakatos, and Ilona Szabó. "Post-epidemic Situation of a Previously Phytophthora alni-infected Common Alder Stand/ Egy korábban Phytophthora alni által fertőzött mézgáséger-állomány járvány utáni állapota." Acta Silvatica et Lignaria Hungarica 11, no. 1 (June 1, 2015): 27–38. http://dx.doi.org/10.1515/aslh-2015-0002.
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Abstract This paper reports on the current situation of the Phytophthora species occurring in a declining common alder (Alnus glutinosa) stand in North-West Hungary. The stand was affected by a severe epidemic caused by Phytophthora alni in the late 1990s. The authors evaluated the health condition of the forest stand and collected soil samples from the rhizosphere of twenty selected trees two times per year in 2011 and in 2012 in order to isolate Phytophthora species. A diverse Phytophthora community was found in the soil consisting of eight species with different aggressiveness and with different ecological demands. Pathogenicity tests confirmed the role of the collected strains in the decline of the alder stand.
Dissertations / Theses on the topic "Phytophthora alni"
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Aguayo, Silva Jaime Cristián. "Étude des conditions de l'émergence du phytophthora alni sur l'aulne glutineux." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0153/document.
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Depuis les années 1990, l'aulne glutineux, espèce clé des ripisylves, est affecté par un oomycète qui cause son dépérissement : Phytophthora alni subsp. alni (Paa). La genèse de Paa est liée à un événement d'hybridation interspécifique entre deux espèces proches, improprement nommées P. alni subsp. uniformis (Pau) et P. alni subsp. multiformis (Pam), car initialement considérées comme des variants de Paa. L'objectif de cette thèse était d'identifier les facteurs ayant pu jouer un rôle dans l'émergence de la maladie en Europe. Par une approche de génétique des populations, nous avons montré que Pau est une espèce invasive en Europe, probablement originaire d'Amérique du Nord. Après son introduction, l'hybridation de Pau avec Pam serait l'un des facteurs essentiels de l'apparition de Paa. Nos résultats confirment que Paa aurait été généré suite à des hybridations récurrentes, qui ont structuré géographiquement les populations en Europe. L'analyse de la variabilité génétique de Paa, révélée par des marqueurs microsatellites, a toutefois montré un faible polymorphisme, avec un génotype dominant largement répandu en Europe. Par ailleurs grâce à la modélisation, nos résultats ont établi que le dépérissement du houppier des aulnes est lié à la température. En particulier l'incidence de la maladie augmente lors des hivers doux, qui pourraient favoriser la survie du mycélium de Paa, celui-ci ne présentant pas de structure de survie hivernale (chlamydospores ou oospores). La température estivale joue également un rôle, plus complexe à interpréter. On constate en effet que l'incidence de la maladie diminue avec l'augmentation des températures estivales, mais ce phénomène pourrait dépendre d'autres facteurs tels que l'état physiologique des arbres ou le type de communautés microbiologiques présentes dans les sols. Inversement, le phénomène de guérison des arbres est favorisé par des températures hivernales basses et par des températures estivales élevées. L'émergence de la maladie ne peut pas être expliquée par le changement climatique. Cependant, une augmentation des températures hivernales dans le futur dans le cadre du changement climatique aggraverait très probablement l'épidémieSince the early 1990's alder decline caused by the oomycete Phytophthora alni subsp. alni (Paa) is one of the most important threats to riparian ecosystems in Europe. The emergence of Paa is related to an interspecific hybridization event between two related species -initially considered as Paa variants- misnamed as Phytophthora alni subsp. uniformis (Pau) and Phytophthora alni subsp. multiformis (Pam). The objective of this thesis was to identify the factors that may have contributed to the emergence of the disease in Europe. Following a population genetics approach we showed that Pau is likely to be an invasive species in Europe, probably native to North America. Its introduction would have enabled hybridization with Pam and, consequently be a major cause on the emergence of Paa. Our results confirm that Paa has arisen from several hybridization events, which have geographically structured its European populations. Paa's genetic variability, revealed by microsatellite markers, showed low levels of polymorphism, with a dominant genotype scattered throughout Europe. In addition, a modelling approach revealed that alders' crown decline is linked to temperature. In particular, the disease incidence increases during mild winters which favours mycelium survival as Paa does not produce resistant spores (chlamydospores or oospores). The effect of summer temperatures is more complex to explain. Disease incidence decreases when summer temperatures are higher, but this phenomenon can also be linked to the physiological conditions of trees or changes in soil microbiological communities. Conversely, tree recovery is favoured by lower winter and higher summer temperatures. Climate change does not explain the emergence of the disease. However, increases in winter temperatures du to climate change may strengthen the epidemic
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Ioos, Renaud Pinon Jean. "Caractérisation génétique de Phytophthora alni Brasier & S.A. Kirk, hybride interspécifique agent du dépérissement de l'aulne en Europe." [S.l.] : [s.n.], 2006. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2006_0105_IOOS.pdf.
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Ioos, Renaud. "Caractérisation génétique de Phytophthora alni Brasier & S. A. Kirk, hybride interspécifique agent du dépérissement de l'aulne en Europe." Nancy 1, 2006. http://docnum.univ-lorraine.fr/public/SCD_T_2006_0105_IOOS.pdf.
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Une maladie émergente causant le dépérissement de l'aulne est causée par un complexe de trois taxons du genre Phytophthora (Oomycète) : P. Alni subsp. Alni (Paa), P. Alni subsp. Multiformis (Pam) et P. Alni subsp. Uniformis (Pau). La première partie de cette étude a consisté à mettre au point des outils de détection spécifiques de ces trois taxons. À partir de SCARs générés par RAPD, nous avons défini trois couples d'amorces de PCR dont l'utilisation combinée permet la détection et l'identification spécifique de Paa, Pam et Pau dans différents substrats (plante, eau, sol). Nous avons ensuite étudié la présence et la distribution allélique pour quatre gènes nucléaires contenant des introns sur une collection de P. Alni et d'espèces proches. L'ADN mitochondrial a également été étudié par RFLP et séquençage de deux gènes. Nous avons montré que i) Pau ne semble pas avoir été généré par hybridation, ii) Pam présente deux allèles fortement divergents pour chaque gène nucléaire et résulterait donc d'une réticulation ou d'une autopolyploïdisation, iii) Paa cumule les allèles présents chez Pam et Pau et a probablement été créé par hybridation entre Pam et Pau ou des taxons très proches. De plus, nous avons étudié le profil d'expression des gènes codant pour des élicitines, famille multigénique spécifique du genre hytophthora. L'additivité des profils de Pau et Pam vis-à-vis de Paa a confirmé nos premiers résultats. Enfin, afin d'étudier la variabilité génétique de ces différents taxons, des marqueurs microsatellites ont été isolés chez Paa et caractérisés. Les génotypes obtenus montrent une faible variabilité chez les trois taxons. Ils confirment nos hypothèses quant à l'origine de Paa et suggèrent que Pam est aussi un taxon allopolyploïdeAn emergent disease of alder is caused by a complex of three taxa belonging to the genus Phytophthora (Oomycetes): P. Alni subsp. Alni (Paa), P. Alni subsp. Multiformis (Pam) and P. Alni subsp. Uniformis (Pau). The first part of this study focused on the development of specific detection tools for these three taxa. Based on SCARs generated with RAPD, we designed three PCR primer pairs which can be combined to specifically detect and identify Paa, Pam and Pau in different substrates (plant tissue, water, soil). Second, we studied the occurrence and the allelic distribution for several nuclear single-copy genes containing introns on a wide collection of P. Alni and close species. Mitochondrial DNA was also studied through RFLP and gene sequencing. We demonstrated that i) Pau may not result from a hybridization event, ii) two divergent alleles for each of the nuclear genes are observed in Pam, which suggests this taxon may have been generated by a reticulation or by autopolyploidisation, iii) Paa combines the alleles observed in Pam and Pau and was probably generated by hybridization between Pam and Pau or Pam- and Pau-like taxa. In addition, we studied the expression of elicitin genes, a multigenic family specific to the genus Phytophthora. The cumulative patterns of Pau and Pam in regard with Paa confirmed our first results. Last, in order to study the genetic variability of the different taxa, microsatellite markers were isolated in Paa and characterized. The genotypes we resolved demonstrate a low level of variability for the three taxa. They confirm our hypotheses in regard with Paa origin and suggest that Pam is also an allopolyploid taxon
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Černý, Karel. "Vnitrodruhová struktura Phytopthora alni Brasier et S. A. Kirk na území ČR." Doctoral thesis, 2013. http://www.nusl.cz/ntk/nusl-177235.
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The work is aimed to study of morphological variability of Phytophthora alni complex in the area of the Czech Republic with use of numerical phenetics. The morphological analysis of 29 Phytophthora alni strains acquired from the area of the pathogen in the Czech Republic was carried out. In total there were studied 50 cultural and morphological characteristics: 14 cultural characteristics, 16 characteristics describing asexual and 20 characteristics describing sexual structures. The all morphological measurements were repeated twenty times at magnification 1600× with use of Olympus BH-2 microscope, Olympus E-510 camera and Quick Photocamera 2.3 measuring software. The data were processed in Statistica 8.0 in modules of non-parametric statistics, descriptive statistics, cluster analysis, analysis of principal components and discriminant analysis. In the area there was confirmed the presence of the two taxa belonging to the P. alni complex: Phytophthora alni subsp. alni (Paa) a Phytophthora alni subsp. uniformis (Pau). The third taxon (P. alni subsp. multiformis) was not found. The nominate subspecies Paa prevailed - more than 4/5 of studied isolates belonged to this taxon. The classification of isolates was in full agreement with molecular study of identical set of isolates which was parallely performed (Štěpánková et al. 2013). The morphological analysis showed, that majority of Czech isolates of P. alni complex can be successfully determined on the basis of standard morphological characters -- oogonial wall ornamentation, antheridial length, rate of aborted oogonia etc. Ca 10 % of isolates were found to be intermediate. All studied isolates were divided with series of cluster and PCA analysis in two relevant clusters and a discriminant function dividing the isolates in the two taxa on basis of morphological characters was generated and validated. The rate of standard oogonia, high of oogonial ornamentation, rate of two-celled antheridia with central septum and antheridial length were used as discriminators. The two different Paa morphotypes were found in the area of the Czech Republic. The discriminant function dividing the Paa isolates in these two morphotypes was also constructed and tested. The discriminators were oogonia diameter, high of oogonial ornamentation and width of antheridium. The most reliable character was the antheridial width: the north-western morphotype has antheridia wider by 3 micrometres than the south-eastern one. The Paa taxon was continuously distributed in the western part of the area, its frequency diminshes eastward. The distribution of the second taxon - Pau - was scattered and insular, but it was found out in the whole area of the Czech Republic. It could be supposed, that the parental taxon Pau had spread before Paa invasion in the area. Later the new and more combative Paa replaced the older weakly pathogenic Pau. The recent area of Pau is apparently insular and probably relict. The two Paa morphotypes importantly differ in their distribution - the first morphotype is more frequent in north-western part of the area (and predominates in western, central and northern Bohemia) while the second one is frequent in the south-eastern part (southern Bohemia and Moravia). Likely, these two subpopulations can represent the remains of colonisation waves of two allopatric Paa lineages. The lineages can originated by repeated independent hybridisation between parental Pau and Pam taxa somewhere in western or central Europe.
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Clemenz, Christian [Verfasser]. "Ökophysiologische und phytopathologische Untersuchungen an Phytophthora alni (Brasier) infizierten Schwarzerlen (Alnus glutinosa [L.] Gaertn.) / Christian Clemenz." 2007. http://d-nb.info/988098849/34.
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Mombour, Janne [Verfasser]. "Ökophysiologische und phytopathologische Untersuchungen an Phytophthora alni -infizierten Schwarzerlen (Alnus glutinosa [L.] Gaertn.) unter besonderer Berücksichtigung der Ausbreitungsdynamik des Pathogens im Rindengewebe / vorgelegt von Janne Mombour." 2009. http://d-nb.info/1003838464/34.
Full textReports on the topic "Phytophthora alni"
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Seeland, T. M., M. E. Ostry, R. Venette, and J. Juzwik. An annotated bibliography of invasive tree pathogens Sirococcus clavigignenti-juglandacearum, Phytophthora alni, and Phytophthora quercina and a regulatory policy and management practices for invasive species. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Research Station, 2006. http://dx.doi.org/10.2737/nc-gtr-270.
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