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J. Keller - One of the best experts on this subject based on the ideXlab platform.
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Ultrastructure de la paroi sporique des Heterobasidiomycetes — I
Persoonia, 1992Co-Authors: J. KellerAbstract:The spore walls in some Auriculariales and Tremellales are analysed to demonstrate an eventual uniformity of structure and to compare it with the construction formed near the apophysis during Sporogenesis. The dolipores of several species are also observed.
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ultrastructure de la paroi sporique des heterobasidiomycetes i
Persoonia, 1992Co-Authors: J. KellerAbstract:The spore walls in some Auriculariales and Tremellales are analysed to demonstrate an eventual uniformity of structure and to compare it with the construction formed near the apophysis during Sporogenesis. The dolipores of several species are also observed.
Regine Kahmann - One of the best experts on this subject based on the ideXlab platform.
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the wopr protein ros1 is a master regulator of Sporogenesis and late effector gene expression in the maize pathogen ustilago maydis
PLOS Pathogens, 2016Co-Authors: Marie Tollot, Daniela Assmann, Christian Becker, Janine Altmuller, Julien Y Dutheil, Carleric Wegner, Regine KahmannAbstract:The biotrophic basidiomycete fungus Ustilago maydis causes smut disease in maize. Hallmarks of the disease are large tumors that develop on all aerial parts of the host in which dark pigmented teliospores are formed. We have identified a member of the WOPR family of transcription factors, Ros1, as major regulator of spore formation in U. maydis. ros1 expression is induced only late during infection and hence Ros1 is neither involved in plant colonization of dikaryotic fungal hyphae nor in plant tumor formation. However, during late stages of infection Ros1 is essential for fungal karyogamy, massive proliferation of diploid fungal cells and spore formation. Premature expression of ros1 revealed that Ros1 counteracts the b-dependent filamentation program and induces morphological alterations resembling the early steps of Sporogenesis. Transcriptional profiling and ChIP-seq analyses uncovered that Ros1 remodels expression of about 30% of all U. maydis genes with 40% of these being direct targets. In total the expression of 80 transcription factor genes is controlled by Ros1. Four of the upregulated transcription factor genes were deleted and two of the mutants were affected in spore development. A large number of b-dependent genes were differentially regulated by Ros1, suggesting substantial changes in this regulatory cascade that controls filamentation and pathogenic development. Interestingly, 128 genes encoding secreted effectors involved in the establishment of biotrophic development were downregulated by Ros1 while a set of 70 “late effectors” was upregulated. These results indicate that Ros1 is a master regulator of late development in U. maydis and show that the biotrophic interaction during Sporogenesis involves a drastic shift in expression of the fungal effectome including the downregulation of effectors that are essential during early stages of infection.
Max L Nibert - One of the best experts on this subject based on the ideXlab platform.
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ictv virus taxonomy profile partitiviridae
Journal of General Virology, 2018Co-Authors: Eeva J Vainio, Nobuhiro Suzuki, Said A Ghabrial, Jiatao Xie, Marilyn J. Roossinck, Sead Sabanadzovic, E Maiss, Sotaro Chiba, Max L NibertAbstract:The Partitiviridae is a family of small, isometric, non-enveloped viruses with bisegmented double-stranded (ds) RNA genomes of 3–4.8 kbp. The two genome segments are individually encapsidated. The family has five genera, with characteristic hosts for members of each genus: either plants or fungi for genera Alphapartitivirus and Betapartitivirus, fungi for genus Gammapartitivirus, plants for genus Deltapartitivirus and protozoa for genus Cryspovirus. Partitiviruses are transmitted intracellularly via seeds (plants), oocysts (protozoa) or hyphal anastomosis, cell division and Sporogenesis (fungi); there are no known natural vectors. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Partitiviridae, which is available at www.ictv.global/report/partitiviridae.
Marie Tollot - One of the best experts on this subject based on the ideXlab platform.
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the wopr protein ros1 is a master regulator of Sporogenesis and late effector gene expression in the maize pathogen ustilago maydis
PLOS Pathogens, 2016Co-Authors: Marie Tollot, Daniela Assmann, Christian Becker, Janine Altmuller, Julien Y Dutheil, Carleric Wegner, Regine KahmannAbstract:The biotrophic basidiomycete fungus Ustilago maydis causes smut disease in maize. Hallmarks of the disease are large tumors that develop on all aerial parts of the host in which dark pigmented teliospores are formed. We have identified a member of the WOPR family of transcription factors, Ros1, as major regulator of spore formation in U. maydis. ros1 expression is induced only late during infection and hence Ros1 is neither involved in plant colonization of dikaryotic fungal hyphae nor in plant tumor formation. However, during late stages of infection Ros1 is essential for fungal karyogamy, massive proliferation of diploid fungal cells and spore formation. Premature expression of ros1 revealed that Ros1 counteracts the b-dependent filamentation program and induces morphological alterations resembling the early steps of Sporogenesis. Transcriptional profiling and ChIP-seq analyses uncovered that Ros1 remodels expression of about 30% of all U. maydis genes with 40% of these being direct targets. In total the expression of 80 transcription factor genes is controlled by Ros1. Four of the upregulated transcription factor genes were deleted and two of the mutants were affected in spore development. A large number of b-dependent genes were differentially regulated by Ros1, suggesting substantial changes in this regulatory cascade that controls filamentation and pathogenic development. Interestingly, 128 genes encoding secreted effectors involved in the establishment of biotrophic development were downregulated by Ros1 while a set of 70 “late effectors” was upregulated. These results indicate that Ros1 is a master regulator of late development in U. maydis and show that the biotrophic interaction during Sporogenesis involves a drastic shift in expression of the fungal effectome including the downregulation of effectors that are essential during early stages of infection.
Józef Bednara - One of the best experts on this subject based on the ideXlab platform.
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The dynamics of the actin cytoskeleton during Sporogenesis in Psilotum nudum L.
Protoplasma, 2011Co-Authors: Dorota Tchórzewska, Józef BednaraAbstract:The actin cytoskeleton (microfilaments, MFs) accompanies the tubulin cytoskeleton (microtubules) during the meiotic division of the cell, but knowledge about the scope of their physiological competence and cooperation is insufficient. To cast more light on this issue, we analysed the F-actin distribution during the meiotic division of the Psilotum nudum sporocytes. Unfixed sporangia of P. nudum were stained with rhodamine-phalloidin and 4′,6-diamidino-2-phenylindole dihydrochloride, and we monitored the changes in the actin cytoskeleton and nuclear chromatin throughout Sporogenesis. We observed that the actin cytoskeleton in meiotically dividing cells is not only part of the kariokinetic spindle and phragmoplast but it also forms a well-developed network in the cytoplasm present in all phases of meiosis. Moreover, in telophase I F-actin filaments formed short-lived phragmoplast, which was adjacent to the plasma membrane, exactly at the site of future cell wall formation. Additionally, the meiocytes were pre-treated with cytochalasin-B at a concentration that causes damage to the MFs. This facilitated observation of the effect of selective MFs damage on the course of meiosis and Sporogenesis of P. nudum . Changes were observed that occurred in the cytochalasin-treated cells: the daughter nuclei were located abnormally close to each other, there was no formation of the equatorial plate of organelles and, consequently, meiosis did not occur normally. It seems possible that, if the actin cytoskeleton only is damaged, regular cytokinesis will not occur and, hence, no viable spores will be produced.
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ORIGINAL ARTICLE The dynamics of the actin cytoskeleton during Sporogenesis
2010Co-Authors: In Psilotum Nudum L, Dorota Tchórzewska, Józef BednaraAbstract:accompanies the tubulin cytoskeleton (microtubules) during the meiotic division of the cell, but knowledge about the scope of their physiological competence and cooperation is insufficient. To cast more light on this issue, we analysed the F-actin distribution during the meiotic division of the Psilotum nudum sporocytes. Unfixed sporangia of P. nudum were stained with rhodamine-phalloidin and 4′,6-diamidino-2-phenylindole dihydrochloride, and we monitored the changes in the actin cytoskeleton and nuclear chromatin throughout Sporogenesis. We observed that the actin cytoskeleton in meiotically dividing cells is not only part of the kariokinetic spindle and phragmoplast but it also forms a well-developed network in the cytoplasm present in all phases of meiosis. Moreover, in telophase I F-actin filaments formed short-lived phragmoplast, which was adjacent to the plasma membrane, exactly at the site of future cell wall formation. Additionally, the meiocytes were pre-treated with cytochalasin-B at a concentration that causes damage to the MFs. This facilitated observation of the effect of selective MFs damage on the course of meiosis and Sporogenesis of P. nudum. Changes were observed that occurred in the cytochalasin-treated cells: the daughter nuclei were located abnormally close to each other, there was no formation of the equatorial plate of organelles and, consequently, meiosis did not occur normally. It seems possible that, if the actin cytoskeleton only is damaged
