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Evolution of intraspecific diversity of invasive pathogen of alder Phytophthora ×alni
Pecka, Štěpán ; Koukol, Ondřej (advisor) ; Sedlářová, Michaela (referee)
Phytophthora alni s. l. (Peronosporomycetes: Stramenopila) is an invasive pathogen causing phytophthora root and collar rot in alders. It has been known from Europe since the '90s and from the Czech Republic since 2001. Three species were found are known within species complex P. alni s. l. Two of these species hybridized in Europe and created third triploid species called Phytophthora ×alni (Phytophthora alni subsp. alni). Dozens of genotypes have been identified with the help of microsatellites in previous studies, nevertheless only one genotype (Pxa-1) was dominating and most of other genotypes were closely related to it. The trend of increasing or decreasing incidence of this genotype differed among these studies. This thesis compares changes in the P. ×alni population in Vltava basin over the last 14 years during which a significant decrease in number of available hosts of this pathogen took place. Multilocus genotypes were determined using a set of 10 microsatellite markers. Among the 94 P. ×alni isolates reliably genotyped, 23 were of different genotypes. None of these genotypes, however, were found on the same localities repeatedly (except the dominant genotype). Incidence of the dominant genotype increased over time (from 63 % to 86 %). Most of the other genotypes were only slightly...
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Invasion of Phytophthora alni in Europe
Pecka, Štěpán ; Černý, Karel (advisor) ; Kolařík, Miroslav (referee)
Species complex Phytophthora alni s. l. (Peronosporomycetes: Stramenopila) is a group of invasive pathogens of alder trees. It spreads mainly via water and causes root and collar rot often resulting in the death of attacked trees. Especially in riparian stands it often causes significant losses of alder and therefore remarcable changes of ecosystems and watercourses. The species complex is very polymorphic and divided into three species - P. ×alni, P. uniformis and P. ×multiformis. The most widespread in Europe and in the Czech Republic is the P. ×alni species. The aim of this thesis is to summarize information about P. alni complex (and especially of the most important taxon P. ×alni), to describe history of its spread and development of its area in Europe, genetic variability and inner structure of its populations, ecology and pathways of spread and, based of the known results, decribe the current situation of the invasion. Key words: Phytophthora alni, Peronosporomycetes, Alnus, pathogen, hybridization, area, riparian stands
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Invasion of Phytophthora alni in Europe
Pecka, Štěpán ; Černý, Karel (advisor) ; Kolařík, Miroslav (referee)
Species complex Phytophthora alni s. l. (Peronosporomycetes: Stramenopila) is a group of invasive pathogens of alder trees. It spreads mainly via water and causes root and collar rot often resulting in the death of attacked trees. Especially in riparian stands it often causes significant losses of alder and therefore remarcable changes of ecosystems and watercourses. The species complex is very polymorphic and divided into three species - P. ×alni, P. uniformis and P. ×multiformis. The most widespread in Europe and in the Czech Republic is the P. ×alni species. The aim of this thesis is to summarize information about P. alni complex (and especially of the most important taxon P. ×alni), to describe history of its spread and development of its area in Europe, genetic variability and inner structure of its populations, ecology and pathways of spread and, based of the known results, decribe the current situation of the invasion. Key words: Phytophthora alni, Peronosporomycetes, Alnus, pathogen, hybridization, area, riparian stands
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