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Barbara Jane Christ - One of the best experts on this subject based on the ideXlab platform.
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in vitro culture of the obligate parasite spongospora subterranea cercozoa Plasmodiophorida associated with root inducing transferred dna transformed potato hairy roots
Journal of Eukaryotic Microbiology, 2007Co-Authors: Xinshun Qu, Barbara Jane ChristAbstract:. Spongospora subterranea is a soil-borne, obligate parasitic protist that causes powdery scab of potatoes. In this study, an in vitro culture system was developed for the maintenance and proliferation of the protist in potato hairy roots. The hairy roots of potato were induced in vitro with Agrobacterium rhizogenes. Cystosori of S. subterranea from potato scab lesions were surface disinfested and used to inoculate potato hairy roots. Plasmodia, zoosporangia, and cystosori were observed microscopically in the hairy roots within 6 wk after inoculation, indicating the completion of the life cycle of S. subterranea in vitro. This is the first in vitro culture system for S. subterranea, and will be a valuable tool to study fundamental and practical aspects of the biology of the parasite.
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In Vitro Culture of the Obligate Parasite Spongospora subterranea (Cercozoa; Plasmodiophorida) Associated with Root‐Inducing Transferred‐DNA Transformed Potato Hairy Roots
Journal of Eukaryotic Microbiology, 2007Co-Authors: Xinshun Qu, Barbara Jane ChristAbstract:. Spongospora subterranea is a soil-borne, obligate parasitic protist that causes powdery scab of potatoes. In this study, an in vitro culture system was developed for the maintenance and proliferation of the protist in potato hairy roots. The hairy roots of potato were induced in vitro with Agrobacterium rhizogenes. Cystosori of S. subterranea from potato scab lesions were surface disinfested and used to inoculate potato hairy roots. Plasmodia, zoosporangia, and cystosori were observed microscopically in the hairy roots within 6 wk after inoculation, indicating the completion of the life cycle of S. subterranea in vitro. This is the first in vitro culture system for S. subterranea, and will be a valuable tool to study fundamental and practical aspects of the biology of the parasite.
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detection and quantification of spongospora subterranea f sp subterranea by pcr in host tissue and naturally infested soils
American Journal of Potato Research, 2006Co-Authors: Xinshun Qu, James A Kavanagh, Damian Egan, Barbara Jane ChristAbstract:A polymerase chain reaction (PCR) assay using primers SsF and SsR designed from the internal transcribed spacer (ITS) regions ofSpongospora subterranea f. sp.subterranea was developed for the specific identification and quantification ofS. subterranea. These primers amplified a 434 bp product from DNA ofS. subterranea spore balls, but not from DNA of healthy potato, common scab tuber, and taxonomically related plasmodiophorids. This PCR assay was successfully used for the detection ofS. subterranea in naturally infected symptomatic and asymptomatic potato tubers.Spongospora subterranea in other infected symptomless host plants was detected by PCR. The PCR assay was modified with improved soil DNA extraction methods to detectS. subterranea in soil. The assay was sensitive, and one spore ball per gram of soil could be detected. Following the design of a heterologous competitor DNA template from the sequence of λDNA, a competitive PCR assay for the quantification ofS. subterranea in soil was developed and provided accurate quantification in the range of 1 to 104 spore balls per 0.25 g of soil. In a preliminary survey of naturally infested field soil samples, spore ball concentrations were estimated to vary from ca 0 to 3600 spore balls per 0.25-g soil sample by this competitive PCR assay. The spore ball levels were compared with the powdery scab disease incidence of potatoes in these fields, and a correlationship between spore ball levels and subsequent disease incidence was found. The PCR assays developed in this investigation can be routinely used to detect and quantifyS. subterranea in diseased plant tissue, asymptomatic plant tissue, and infested soil.
Xinshun Qu - One of the best experts on this subject based on the ideXlab platform.
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in vitro culture of the obligate parasite spongospora subterranea cercozoa Plasmodiophorida associated with root inducing transferred dna transformed potato hairy roots
Journal of Eukaryotic Microbiology, 2007Co-Authors: Xinshun Qu, Barbara Jane ChristAbstract:. Spongospora subterranea is a soil-borne, obligate parasitic protist that causes powdery scab of potatoes. In this study, an in vitro culture system was developed for the maintenance and proliferation of the protist in potato hairy roots. The hairy roots of potato were induced in vitro with Agrobacterium rhizogenes. Cystosori of S. subterranea from potato scab lesions were surface disinfested and used to inoculate potato hairy roots. Plasmodia, zoosporangia, and cystosori were observed microscopically in the hairy roots within 6 wk after inoculation, indicating the completion of the life cycle of S. subterranea in vitro. This is the first in vitro culture system for S. subterranea, and will be a valuable tool to study fundamental and practical aspects of the biology of the parasite.
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In Vitro Culture of the Obligate Parasite Spongospora subterranea (Cercozoa; Plasmodiophorida) Associated with Root‐Inducing Transferred‐DNA Transformed Potato Hairy Roots
Journal of Eukaryotic Microbiology, 2007Co-Authors: Xinshun Qu, Barbara Jane ChristAbstract:. Spongospora subterranea is a soil-borne, obligate parasitic protist that causes powdery scab of potatoes. In this study, an in vitro culture system was developed for the maintenance and proliferation of the protist in potato hairy roots. The hairy roots of potato were induced in vitro with Agrobacterium rhizogenes. Cystosori of S. subterranea from potato scab lesions were surface disinfested and used to inoculate potato hairy roots. Plasmodia, zoosporangia, and cystosori were observed microscopically in the hairy roots within 6 wk after inoculation, indicating the completion of the life cycle of S. subterranea in vitro. This is the first in vitro culture system for S. subterranea, and will be a valuable tool to study fundamental and practical aspects of the biology of the parasite.
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detection and quantification of spongospora subterranea f sp subterranea by pcr in host tissue and naturally infested soils
American Journal of Potato Research, 2006Co-Authors: Xinshun Qu, James A Kavanagh, Damian Egan, Barbara Jane ChristAbstract:A polymerase chain reaction (PCR) assay using primers SsF and SsR designed from the internal transcribed spacer (ITS) regions ofSpongospora subterranea f. sp.subterranea was developed for the specific identification and quantification ofS. subterranea. These primers amplified a 434 bp product from DNA ofS. subterranea spore balls, but not from DNA of healthy potato, common scab tuber, and taxonomically related plasmodiophorids. This PCR assay was successfully used for the detection ofS. subterranea in naturally infected symptomatic and asymptomatic potato tubers.Spongospora subterranea in other infected symptomless host plants was detected by PCR. The PCR assay was modified with improved soil DNA extraction methods to detectS. subterranea in soil. The assay was sensitive, and one spore ball per gram of soil could be detected. Following the design of a heterologous competitor DNA template from the sequence of λDNA, a competitive PCR assay for the quantification ofS. subterranea in soil was developed and provided accurate quantification in the range of 1 to 104 spore balls per 0.25 g of soil. In a preliminary survey of naturally infested field soil samples, spore ball concentrations were estimated to vary from ca 0 to 3600 spore balls per 0.25-g soil sample by this competitive PCR assay. The spore ball levels were compared with the powdery scab disease incidence of potatoes in these fields, and a correlationship between spore ball levels and subsequent disease incidence was found. The PCR assays developed in this investigation can be routinely used to detect and quantifyS. subterranea in diseased plant tissue, asymptomatic plant tissue, and infested soil.
Martin Kirchmair - One of the best experts on this subject based on the ideXlab platform.
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Vitis 43 (4), 187–189 (2004) First record of a plasmodiophorid parasite in grapevine
2016Co-Authors: L. Huber, M. Hammes, Gerhard Eisenbeis, Reinhold Pöder, Martin KirchmairAbstract:In the context of an interdisciplinary project on grape pests and pathogens in Rheingau (Germany), the fine root system of grafted rootstocks has been screened for patho-genic fungi associated with root galls induced by grape phylloxera (Daktulosphaira vitifoliae (Fitch)). In several insect-induced galls, masses of resting spores of a plasmodiophorid could be seen. An additional selective screening revealed the occurrence of the plasmodiophorid parasite also in samples of gall-free rootlets: cortical cells of small necrotic areas were crowded with resting spores or other developmental stages of its life cycle. According to current taxonomic concepts, this plasmodiophorid could be identified as a member of the genus Sorosphaera Schroeter, resembling S. veronicae Schroeter. This is the first record of a plasmodiophorid parasite in grapevine. K e y w o r d s: Plant pathogen, soil, sporosori, Sorosphaera, Vitis
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First record of a plasmodiophorid parasite in grapevine
Vitis: Journal of Grapevine Research, 2015Co-Authors: L. Huber, M. Hammes, Gerhard Eisenbeis, Reinhold Pöder, Martin KirchmairAbstract:In the context of an interdisciplinary project on grape pests and pathogens in Rheingau (Germany), the fine root system of grafted rootstocks has been screened for pathogenic fungi associated with root galls induced by grape phylloxera ( Daktulosphaira vitifoliae (Fitch)). In several insect-induced galls, masses of resting spores of a plasmodiophorid could be seen. An additional selective screening revealed the occurrence of the plasmodiophorid parasite also in samples of gall-free rootlets: cortical cells of small necrotic areas were crowded with resting spores or other developmental stages of its life cycle. According to current taxonomic concepts, this plasmodiophorid could be identified as a member of the genus Sorosphaera Schroeter, resembling S. veronicae Schroeter. This is the first record of a plasmodiophorid parasite in grapevine.
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Cross-kingdom host shifts of phytomyxid parasites
BMC Evolutionary Biology, 2014Co-Authors: Sigrid Neuhauser, Simon Bulman, Martin Kirchmair, David BassAbstract:Background Phytomyxids (plasmodiophorids and phagomyxids) are cosmopolitan, obligate biotrophic protist parasites of plants, diatoms, oomycetes and brown algae. Plasmodiophorids are best known as pathogens or vectors for viruses of arable crops (e.g. clubroot in brassicas, powdery potato scab, and rhizomania in sugar beet). Some phytomyxid parasites are of considerable economic and ecologic importance globally, and their hosts include important species in marine and terrestrial environments. However most phytomyxid diversity remains uncharacterised and knowledge of their relationships with host taxa is very fragmentary. Results Our molecular and morphological analyses of phytomyxid isolates–including for the first time oomycete and sea-grass parasites–demonstrate two cross-kingdom host shifts between closely related parasite species: between angiosperms and oomycetes, and from diatoms/brown algae to angiosperms. Switching between such phylogenetically distant hosts is generally unknown in host-dependent eukaryote parasites. We reveal novel plasmodiophorid lineages in soils, suggesting a much higher diversity than previously known, and also present the most comprehensive phytomyxid phylogeny to date. Conclusion Such large-scale host shifts between closely related obligate biotrophic eukaryote parasites is to our knowledge unique to phytomyxids. Phytomyxids may readily adapt to a wide diversity of new hosts because they have retained the ability to covertly infect alternative hosts. A high cryptic diversity and ubiquitous distribution in agricultural and natural habitats implies that in a changing environment phytomyxids could threaten the productivity of key species in marine and terrestrial environments alike via host shift speciation.
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Sorosphaerula nom. n. for the plasmodiophorid genus Sorosphaera J. Schröter 1886 (Rhizaria: Endomyxa: Phytomyxea: Plasmodiophorida).
The Journal of eukaryotic microbiology, 2011Co-Authors: Sigrid Neuhauser, Martin KirchmairAbstract:. Sorosphaerula nom. n. is introduced to replace the phytomyxean generic name Sorosphaera J. Schroter, which is preoccupied by the foraminiferan genus Sorosphaera Brady. As it is agreed now that both the Foraminifera and the Phytomyxea belong to the Rhizaria, this homonomy within the same supergroup of eukaryotes needs to be revised. To avoid future homonomy, we recommend that the International Code of Zoological Nomenclature be applied for future taxonomic work on Phytomyxea.
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The ecological potentials of Phytomyxea (“plasmodiophorids”) in aquatic food webs
Hydrobiologia, 2011Co-Authors: Sigrid Neuhauser, Martin Kirchmair, Frank H. GleasonAbstract:The Phytomyxea (“plasmodiophorids”) including both Plasmodiophorida and Phagomyxida is a monophyletic group of Eukaryotes composed of obligate biotrophic parasites of green plants, brown algae, diatoms and stramenopiles commonly found in many freshwater, soil and marine environments. However, most research on Phytomyxea has been restricted to plant pathogenic species with agricultural importance, thereby missing the huge ecological potential of this enigmatic group of parasites. Members of the Phytomyxea can induce changes in biomass in their hosts (e.g. hypertrophies of the host tissue) under suitable environmental conditions. Upon infection they alter the metabolism of their hosts, consequently changing the metabolic status of their host. This results in an altered chemical composition of the host tissue, which impacts the diversity of species which feed on the tissues of the infected host and on the zoospores produced by the parasites. Furthermore, significant amounts of nutrients derived from the hosts, both primary producers (plants and algae) and primary consumers (litter decomposers and plant parasites [Oomycetes]), can enter the food web at different trophic levels in form of zoospores and resting spores. Large numbers of zoospores and resting spores are produced which can be eaten by secondary and tertiary consumers, such as grazing zooplankton and metazoan filter-feeders. Therefore, these microbes can act as energy-rich nutrient resources which may significantly alter the trophic relationships in fresh water, soil and marine habitats. Based on the presented data, Phytomyxea can significantly contribute to the complexity and energy transfer within food webs.
M J Adams - One of the best experts on this subject based on the ideXlab platform.
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the use of conventional and quantitative real time pcr assays for polymyxa graminis to examine host plant resistance inoculum levels and intraspecific variation
New Phytologist, 2004Co-Authors: E Ward, K Kanyuka, J Motteram, D Kornyukhin, M J AdamsAbstract:Summary • A real-time PCR protocol based on 18S rDNA sequences was developed to provide a specific, sensitive and quantitative assay for the root-infecting virus vector Polymyxa graminis. • The assay was calibrated with zoospore suspensions and inoculated roots and then shown to work with naturally infected plant roots and infested soil. Both the temperate P. graminis ribotypes previously described are detected but are not distinguished. DNA from related plasmodiophorids and from a range of fungi and plants was not detected. • Different genotypes of Triticum were grown in a soil infested with P. graminis and Soil-borne cereal mosaic virus (SBCMV). The genotypes differed in susceptibility to P. graminis, the least susceptible being the Triticum monococcum accession K-58505. • Conventional PCR assays and sequencing of amplified rDNA fragments showed that P. graminis isolates infecting wheat were mostly, but not exclusively, of ribotype II. Ribotype II was clearly associated with SBCMV transmission and seems to occur preferentially on wheat whereas ribotype I is mostly associated with barley.
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polymyxa graminis and the cereal viruses it transmits a research challenge
Molecular Plant Pathology, 2003Co-Authors: Konstantin Kanyuka, E Ward, M J AdamsAbstract:UNLABELLED SUMMARY Polymyxa graminis is a eukaryotic obligate biotrophic parasite of plant roots that belongs to a poorly studied discrete taxonomic unit informally called the 'plasmodiophorids'. P. graminis is non-pathogenic, but has the ability to acquire and transmit a range of plant viruses which cause serious diseases in cereal crop species and result in significant yield reductions. The viruses are protected from the environment within P. graminis resting spores ('cysts') that may remain dormant but viable for decades (probably until a suitable host plant is encountered). The persistent, soil-borne nature of these diseases makes the use of virus-resistant crop varieties currently the only practical and environmentally friendly means of control. USEFUL WEBSITES http://www.rothamsted.bbsrc.ac.uk/ppi/links/pplinks/plasmod/index.html, http://www.dpvweb.net/, http://www.rothamsted.bbsrc.ac.uk/ppi/Iwgpvfv/index.html, http://www.rothamsted.bbsrc.ac.uk/ppi/links/pplinks/bymoviruses/index.html, http://oak.cats.ohiou.edu/~braselto/plasmos/
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analysis of ribosomal dna sequences of polymyxa species and related fungi and the development of genus and species specific pcr primers
Fungal Biology, 1998Co-Authors: E Ward, M J AdamsAbstract:A region of about 800 bp of ribosomal DNA has been sequenced in 10 isolates of Polymyxa and one isolate each of Plasmodiophora brassicae and the chytrid Olpidium brassicae. This region consists of about 330 bp at the 3′ end of the 18S gene, the 5-8S DNA and the two internal transcribed spacers. A shorter region was also sequenced from one isolate each of Spongospora subterranea and a Ligniera sp. The results supported the earlier division of P. graminis into three subgroups and the recognition of P. betae as a distinct species. In phylogenetic analyses, the Ligniera and Spongospora isolates grouped with the other plasmodiophorids and the Olpidium isolate with the Mycota. The plasmodiophorids appeared as a distinct group and were not closely related to any other eukaryotes (including a range of fungi and protozoa). The DNA sequences were used to design primers for specific amplification of either Polymyxa or P. graminis DNA.
Sigrid Neuhauser - One of the best experts on this subject based on the ideXlab platform.
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draft genome resource for the potato powdery scab pathogen spongospora subterranea
Molecular Plant-microbe Interactions, 2018Co-Authors: Stefan Ciaghi, Sigrid Neuhauser, Arne SchwelmAbstract:: The Plasmodiophorida (Phytomyxea, Rhizaria) are a group of protists that infect plants. Of this group, Spongospora subterranea causes major problems for the potato industry by causing powdery scab and root galling of potatoes and as vector for the Potato mop-top virus (PMTV) (genus Pomovirus, family Virgaviridae). A single tuber isolate (SSUBK13) of this uncultivable protist was used to generate DNA for Illumina sequencing. The data were assembled to a draft genome of 28.08 Mb consisting of 2,340 contigs and an L50 of 280. A total of 10,778 genes were predicted and 93% of the BUSCO genes were detected. The presented genome assembly is only the second genome of a plasmodiophorid. The data will accelerate functional genomics to study poorly understood interaction of plasmodiophorids and their hosts.
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DataSheet1.pdf
2018Co-Authors: David Bass, Sigrid Neuhauser, Christopher Van Der Gast, Serena Thomson, Sally Hilton, Gary D. BendingAbstract:Microbial communities closely associated with the rhizosphere can have strong positive and negative impacts on plant health and growth. We used a group-specific amplicon approach to investigate local scale drivers in the diversity and distribution of plasmodiophorids in rhizosphere/root and bulk soil samples from oilseed rape (OSR) and wheat agri-systems. Plasmodiophorids are plant- and stramenopile-associated protists including well known plant pathogens as well as symptomless endobiotic species. We detected 28 plasmodiophorid lineages (OTUs), many of them novel, and showed that plasmodiophorid communities were highly dissimilar and significantly divergent between wheat and OSR rhizospheres and between rhizosphere and bulk soil samples. Bulk soil communities were not significantly different between OSR and wheat systems. Wheat and OSR rhizospheres selected for different plasmodiophorid lineages. An OTU corresponding to Spongospora nasturtii was positively selected in the OSR rhizosphere, as were two genetically distinct OTUs. Two novel lineages related to Sorosphaerula veronicae were significantly associated with wheat rhizosphere samples, indicating unknown plant-protist relationships. We show that group-targeted eDNA approaches to microbial symbiont-host ecology reveal significant novel diversity and enable inference of differential activity and potential interactions between sequence types, as well as their presence.
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Cross-kingdom host shifts of phytomyxid parasites
BMC Evolutionary Biology, 2014Co-Authors: Sigrid Neuhauser, Simon Bulman, Martin Kirchmair, David BassAbstract:Background Phytomyxids (plasmodiophorids and phagomyxids) are cosmopolitan, obligate biotrophic protist parasites of plants, diatoms, oomycetes and brown algae. Plasmodiophorids are best known as pathogens or vectors for viruses of arable crops (e.g. clubroot in brassicas, powdery potato scab, and rhizomania in sugar beet). Some phytomyxid parasites are of considerable economic and ecologic importance globally, and their hosts include important species in marine and terrestrial environments. However most phytomyxid diversity remains uncharacterised and knowledge of their relationships with host taxa is very fragmentary. Results Our molecular and morphological analyses of phytomyxid isolates–including for the first time oomycete and sea-grass parasites–demonstrate two cross-kingdom host shifts between closely related parasite species: between angiosperms and oomycetes, and from diatoms/brown algae to angiosperms. Switching between such phylogenetically distant hosts is generally unknown in host-dependent eukaryote parasites. We reveal novel plasmodiophorid lineages in soils, suggesting a much higher diversity than previously known, and also present the most comprehensive phytomyxid phylogeny to date. Conclusion Such large-scale host shifts between closely related obligate biotrophic eukaryote parasites is to our knowledge unique to phytomyxids. Phytomyxids may readily adapt to a wide diversity of new hosts because they have retained the ability to covertly infect alternative hosts. A high cryptic diversity and ubiquitous distribution in agricultural and natural habitats implies that in a changing environment phytomyxids could threaten the productivity of key species in marine and terrestrial environments alike via host shift speciation.
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Phylogenetic tree of the partial 18S rDNA gene sequences from the novel Maullinia sp. which is parasitic in Durvillaea antarctica.
2013Co-Authors: Franz Goecke, Jutta Wiese, Alejandra Núñez, Antje Labes, Johannes F. Imhoff, Sigrid NeuhauserAbstract:Maullinia sp. (JX163857) is placed within the Phagomyxida and sister to the second brown algal parasitic species of Phytomyxea Maullinia ectocarpii. The phylogenetic tree was constructed using Bayesian analyses running the GTR+I+R model with 1000000 generations (burnin = 1000). Posterior probabilities are shown above the nodes. The resolution of the branches within the Plasmodiophorida was better supported in PHYML analyses (data not shown).
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Sorosphaerula nom. n. for the plasmodiophorid genus Sorosphaera J. Schröter 1886 (Rhizaria: Endomyxa: Phytomyxea: Plasmodiophorida).
The Journal of eukaryotic microbiology, 2011Co-Authors: Sigrid Neuhauser, Martin KirchmairAbstract:. Sorosphaerula nom. n. is introduced to replace the phytomyxean generic name Sorosphaera J. Schroter, which is preoccupied by the foraminiferan genus Sorosphaera Brady. As it is agreed now that both the Foraminifera and the Phytomyxea belong to the Rhizaria, this homonomy within the same supergroup of eukaryotes needs to be revised. To avoid future homonomy, we recommend that the International Code of Zoological Nomenclature be applied for future taxonomic work on Phytomyxea.