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Marjatta Raudaskoski - One of the best experts on this subject based on the ideXlab platform.
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t dna transfer and integration in the ectomycorrhizal fungus Suillus bovinus using hygromycin b as a selectable marker
Current Genetics, 2002Co-Authors: Mubashir Hanif, Alejandro G Pardo, Markus Gorfer, Marjatta RaudaskoskiAbstract:The T-DNA of Agrobacterium tumefaciens can be transferred to plants, yeasts, fungi and human cells. Using this system, dikaryotic mycelium of the ectomycorrhizal fungus Suillus bovinus was transformed with recombinant hygromycin B phosphotransferase (hph) and enhanced green fluorescent protein (EGFP) genes fused with a heterologous fungal promoter and CaMV 35S terminator. Transformation resulted in hygromycin B-resistant clones, which were mitotically stable. Putative transformants were analysed for the presence of hph and EGFP genes by PCR and Southern analysis. The latter analysis proved both multiple- and single-copy integrations of the genes in the S. bovinus genome. A. tumefaciens transformation should make possible the development of tagged mutagenesis and targeted gene disruption technology for S. bovinus.
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characterization of small gtpases cdc42 and rac and the relationship between cdc42 and actin cytoskeleton in vegetative and ectomycorrhizal hyphae of Suillus bovinus
Molecular Plant-microbe Interactions, 2001Co-Authors: Markus Gorfer, Mika T. Tarkka, Mubashir Hanif, Alejandro G Pardo, Erja Laitiainen, Marjatta RaudaskoskiAbstract:This work reports the isolation and molecular characterization of CDC42 and RAC1 cDNAs from the ectomycorrhiza forming filamentous homobasidiomycete Suillus bovinus. Previously, no RAC gene was described from filamentous fungi and no CDC42 gene was described from homobasidiomycetes. Southern hybridization with SbCDC42 and SbRAC1 cDNAs indicated that the S. bovinus genome contains only one CDC42 and one RAC1 gene. The predicted amino acid sequence of SbRac1p is 77% identical with the Rac1B protein of chick, whereas SbCdc42p is most identical with Schizosaccharomyces pombe Cdc42p, showing 88% identity. In the predicted amino acid sequences of SbRac1p and SbCdc42p, the five guanine nucleotide binding regions, switch I and II, and the effector domain are highly identical to those known in other small GTPases. These domain structures suggest that in S. bovinus, SbRac1p and SbCdc42p function as molecular switches regulating the organization of actin cytoskeleton, similar to yeasts and mammals. SbRAC1 and SbCDC4...
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molecular characterization of actin genes from homobasidiomycetes two different actin genes from schizophyllum commune and Suillus bovinus
Gene, 2000Co-Authors: Mika T. Tarkka, Markus Gorfer, Ritva Vasara, Marjatta RaudaskoskiAbstract:The actin-encoding genes Scact1 and Scact2 of the homobasidiomycete Schizophyllum commune are the first actin genes isolated from higher filamentous fungi. Their isolation shows that homobasidiomycetes have two actin encoding genes instead of one typical to yeasts and filamentous ascomycetes. This result was further confirmed by cloning two actin encoding genes, Sbact1 and Sbact2, from another homobasidiomycete Suillus bovinus. The comparison of the genomic and cDNA sequences of the actin genes showed that Scact1 and Scact2 genes of S. commune contain seven introns, five of which are at the same position in the two genes while S. bovinus actin genes contain nine similarly positioned introns. In the four genes, five intron positions are shared, which indicates a close relationship between the actin encoding genes from S. commune and S. bovinus. Northern hybridization and analysis of two-dimensional immunoblots showed a diVerence in the expression levels between the two actin genes in each fungus. No actin protein could be detected from S. commune Scact2. The deduced amino acid sequence of the Scact2 gene also diVers considerably from any other known actin protein. These data suggest that the Scact2 gene either has a special as yet unidentified function in S. commune life cycle or is a transcribed but no longer translated pseudogene. Scact2 gene has a putative mORF (short open reading frame) and Scact1 gene an intron in the 5ae-untranslated region, which could reduce the translational eYciency and increase the transcriptional eYciency of the Scact2 and Scact1 genes, respectively. During mating in S. commune or at formation of ectomycorrhiza in S. bovinus, the expression of actin genes was similar to that in vegetative hyphae. This result suggests that the reorganization of actin cytoskeleton in response to extra- and intracellular signals in higher filamentous fungi could be directly regulated by members of signalling pathways well characterized in yeast and mammalian cells. © 2000 Elsevier Science B.V. All rights reserved.
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Developmentally regulated proteins during differentiation of root system and ectomycorrhiza in Scots pine (Pinus sylvestris) with Suillus bovinus
Physiologia Plantarum, 1998Co-Authors: Mika T. Tarkka, Sara S. Niini, Marjatta RaudaskoskiAbstract:Total and radiolabelled proteins from Pinus sylvestris roots, ectomycorrhiza and the ectomycorrhizal fungus Suillus bovinus, were analyzed after separation by 2-D gel electrophoresis. The purpose was to address the contribution of individual proteins to the development of ectomycorrhiza. In Pinus sylvestris, ectomycorrhiza forms only in the short roots and therefore special attention was paid to the proteins of short roots before formation of ectomycorrhiza. A main result, from comparisons of protein amounts in main and lateral root tips and short roots, was that the specialized growth pattern of short roots is associated with the production of five short root-specific proteins, and that several proteins of the main and lateral roots are repressed in short roots. At the morphologically different stages of the ectomycorrhiza, only few changes appeared in the amounts of the host and the symbiont proteins. Only one ectomycorrhiza-specific protein could be distinguished.
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Tubulin and actin protein patterns in Scots pine (Pinus sylvestris) roots and developing ectomycorrhiza with Suillus bovinus
Physiologia Plantarum, 1996Co-Authors: Sara S. Niini, Mika T. Tarkka, Marjatta RaudaskoskiAbstract:The role of tubulin and actin in the development of Scots pine (Pinus sylvestris) roots and in the formation of the ectomycorrhiza with the basidiomycete Suillus bovinus was studied by immunoblotting of 2D-gels with anti-tubulin and anti-actin antibodies. In the short roots the α-tubulin pattern was different from that in the other root types due to the more acidic pI of the two α-tubulins. During the formation of the ectomycorrhiza, two new α-tubulins were detected in the acidic α-tubulin cluster. No such variation occurred in the plant β-tubulin patterns. The fungal tubulins dominated in the ectomycorrhiza, but no changes in tubulin polypeptide patterns from those in the S. bovinus mycelium were observed. Contrary to the tubulins, plant actin dominated in the mycorrhiza. The specific α-tubulin patterns of uninfected and infected short roots indicate that α-tubulin is involved in the morphogenesis of Pinus sylvestris short roots. The high level of plant actin at early stage of the mycorrhiza formation suggests a significant role of this protein in the interaction between plant cells and fungal hyphae.
Mika T. Tarkka - One of the best experts on this subject based on the ideXlab platform.
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Two phylogenetically highly distinct β-tubulin genes of the basidiomycete Suillus bovinus
Current Genetics, 2005Co-Authors: Jarmo T. Juuti, Mika T. Tarkka, Sanna Jokela, Lars Paulin, Jarkko LahdensaloAbstract:Genes tubb1 and tubb2 which encode β-tubulins 1 and 2, respectively, were characterised from the ectomycorrhizal basidiomycete Suillus bovinus . The two β-tubulins are surprisingly divergent, with the lowest known sequence identity (60%) in any single fungal species. Comparative analysis showed that β-tubulin 1 and the intron distribution within the tubb1 gene resemble the other β-tubulins. β-Tubulin 2, in contrast, is the most divergent fully described fungal β-tubulin and the gene contains at least 21 introns, which is the largest amount known for any β-tubulin gene. Despite this divergence, both genes are constitutively expressed in the functional compartments of the mycorrhizosphere and in pure cultures. Transcription of tubb1 is about 2.4 times higher than that of tubb2 ; and this difference is also seen at the translation level. Evidence suggested that phosphorylation may be the main post-translational modification of both β-tubulins. The putative GTP-binding site residues of β-tubulin 1 match crystallised pig β-tubulin residues, while five of the nine differences in β-tubulin 2 match the pig α-tubulin GTP-site, suggesting the presence of adaptive sequence evolution. In a Bayesian analysis, β-tubulin 1 joins the other basidiomycete sequences, while β-tubulin 2 loosely associates with the group of divergent ascomycete sequences without any clear relative among the known full-length fungal β-tubulin sequences.
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two phylogenetically highly distinct β tubulin genes of the basidiomycete Suillus bovinus
Current Genetics, 2005Co-Authors: Jarmo T. Juuti, Mika T. Tarkka, Sanna Jokela, Lars Paulin, Jarkko LahdensaloAbstract:Genes tubb1 and tubb2 which encode beta-tubulins 1 and 2, respectively, were characterised from the ectomycorrhizal basidiomycete Suillus bovinus. The two beta-tubulins are surprisingly divergent, with the lowest known sequence identity (60%) in any single fungal species. Comparative analysis showed that beta-tubulin 1 and the intron distribution within the tubb1 gene resemble the other beta-tubulins. beta-Tubulin 2, in contrast, is the most divergent fully described fungal beta-tubulin and the gene contains at least 21 introns, which is the largest amount known for any beta-tubulin gene. Despite this divergence, both genes are constitutively expressed in the functional compartments of the mycorrhizosphere and in pure cultures. Transcription of tubb1 is about 2.4 times higher than that of tubb2; and this difference is also seen at the translation level. Evidence suggested that phosphorylation may be the main post-translational modification of both beta-tubulins. The putative GTP-binding site residues of beta-tubulin 1 match crystallised pig beta-tubulin residues, while five of the nine differences in beta-tubulin 2 match the pig alpha-tubulin GTP-site, suggesting the presence of adaptive sequence evolution. In a Bayesian analysis, beta-tubulin 1 joins the other basidiomycete sequences, while beta-tubulin 2 loosely associates with the group of divergent ascomycete sequences without any clear relative among the known full-length fungal beta-tubulin sequences.
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characterization of small gtpases cdc42 and rac and the relationship between cdc42 and actin cytoskeleton in vegetative and ectomycorrhizal hyphae of Suillus bovinus
Molecular Plant-microbe Interactions, 2001Co-Authors: Markus Gorfer, Mika T. Tarkka, Mubashir Hanif, Alejandro G Pardo, Erja Laitiainen, Marjatta RaudaskoskiAbstract:This work reports the isolation and molecular characterization of CDC42 and RAC1 cDNAs from the ectomycorrhiza forming filamentous homobasidiomycete Suillus bovinus. Previously, no RAC gene was described from filamentous fungi and no CDC42 gene was described from homobasidiomycetes. Southern hybridization with SbCDC42 and SbRAC1 cDNAs indicated that the S. bovinus genome contains only one CDC42 and one RAC1 gene. The predicted amino acid sequence of SbRac1p is 77% identical with the Rac1B protein of chick, whereas SbCdc42p is most identical with Schizosaccharomyces pombe Cdc42p, showing 88% identity. In the predicted amino acid sequences of SbRac1p and SbCdc42p, the five guanine nucleotide binding regions, switch I and II, and the effector domain are highly identical to those known in other small GTPases. These domain structures suggest that in S. bovinus, SbRac1p and SbCdc42p function as molecular switches regulating the organization of actin cytoskeleton, similar to yeasts and mammals. SbRAC1 and SbCDC4...
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molecular characterization of actin genes from homobasidiomycetes two different actin genes from schizophyllum commune and Suillus bovinus
Gene, 2000Co-Authors: Mika T. Tarkka, Markus Gorfer, Ritva Vasara, Marjatta RaudaskoskiAbstract:The actin-encoding genes Scact1 and Scact2 of the homobasidiomycete Schizophyllum commune are the first actin genes isolated from higher filamentous fungi. Their isolation shows that homobasidiomycetes have two actin encoding genes instead of one typical to yeasts and filamentous ascomycetes. This result was further confirmed by cloning two actin encoding genes, Sbact1 and Sbact2, from another homobasidiomycete Suillus bovinus. The comparison of the genomic and cDNA sequences of the actin genes showed that Scact1 and Scact2 genes of S. commune contain seven introns, five of which are at the same position in the two genes while S. bovinus actin genes contain nine similarly positioned introns. In the four genes, five intron positions are shared, which indicates a close relationship between the actin encoding genes from S. commune and S. bovinus. Northern hybridization and analysis of two-dimensional immunoblots showed a diVerence in the expression levels between the two actin genes in each fungus. No actin protein could be detected from S. commune Scact2. The deduced amino acid sequence of the Scact2 gene also diVers considerably from any other known actin protein. These data suggest that the Scact2 gene either has a special as yet unidentified function in S. commune life cycle or is a transcribed but no longer translated pseudogene. Scact2 gene has a putative mORF (short open reading frame) and Scact1 gene an intron in the 5ae-untranslated region, which could reduce the translational eYciency and increase the transcriptional eYciency of the Scact2 and Scact1 genes, respectively. During mating in S. commune or at formation of ectomycorrhiza in S. bovinus, the expression of actin genes was similar to that in vegetative hyphae. This result suggests that the reorganization of actin cytoskeleton in response to extra- and intracellular signals in higher filamentous fungi could be directly regulated by members of signalling pathways well characterized in yeast and mammalian cells. © 2000 Elsevier Science B.V. All rights reserved.
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Developmentally regulated proteins during differentiation of root system and ectomycorrhiza in Scots pine (Pinus sylvestris) with Suillus bovinus
Physiologia Plantarum, 1998Co-Authors: Mika T. Tarkka, Sara S. Niini, Marjatta RaudaskoskiAbstract:Total and radiolabelled proteins from Pinus sylvestris roots, ectomycorrhiza and the ectomycorrhizal fungus Suillus bovinus, were analyzed after separation by 2-D gel electrophoresis. The purpose was to address the contribution of individual proteins to the development of ectomycorrhiza. In Pinus sylvestris, ectomycorrhiza forms only in the short roots and therefore special attention was paid to the proteins of short roots before formation of ectomycorrhiza. A main result, from comparisons of protein amounts in main and lateral root tips and short roots, was that the specialized growth pattern of short roots is associated with the production of five short root-specific proteins, and that several proteins of the main and lateral roots are repressed in short roots. At the morphologically different stages of the ectomycorrhiza, only few changes appeared in the amounts of the host and the symbiont proteins. Only one ectomycorrhiza-specific protein could be distinguished.
Jarmo T. Juuti - One of the best experts on this subject based on the ideXlab platform.
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Two phylogenetically highly distinct β-tubulin genes of the basidiomycete Suillus bovinus
Current Genetics, 2005Co-Authors: Jarmo T. Juuti, Mika T. Tarkka, Sanna Jokela, Lars Paulin, Jarkko LahdensaloAbstract:Genes tubb1 and tubb2 which encode β-tubulins 1 and 2, respectively, were characterised from the ectomycorrhizal basidiomycete Suillus bovinus . The two β-tubulins are surprisingly divergent, with the lowest known sequence identity (60%) in any single fungal species. Comparative analysis showed that β-tubulin 1 and the intron distribution within the tubb1 gene resemble the other β-tubulins. β-Tubulin 2, in contrast, is the most divergent fully described fungal β-tubulin and the gene contains at least 21 introns, which is the largest amount known for any β-tubulin gene. Despite this divergence, both genes are constitutively expressed in the functional compartments of the mycorrhizosphere and in pure cultures. Transcription of tubb1 is about 2.4 times higher than that of tubb2 ; and this difference is also seen at the translation level. Evidence suggested that phosphorylation may be the main post-translational modification of both β-tubulins. The putative GTP-binding site residues of β-tubulin 1 match crystallised pig β-tubulin residues, while five of the nine differences in β-tubulin 2 match the pig α-tubulin GTP-site, suggesting the presence of adaptive sequence evolution. In a Bayesian analysis, β-tubulin 1 joins the other basidiomycete sequences, while β-tubulin 2 loosely associates with the group of divergent ascomycete sequences without any clear relative among the known full-length fungal β-tubulin sequences.
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two phylogenetically highly distinct β tubulin genes of the basidiomycete Suillus bovinus
Current Genetics, 2005Co-Authors: Jarmo T. Juuti, Mika T. Tarkka, Sanna Jokela, Lars Paulin, Jarkko LahdensaloAbstract:Genes tubb1 and tubb2 which encode beta-tubulins 1 and 2, respectively, were characterised from the ectomycorrhizal basidiomycete Suillus bovinus. The two beta-tubulins are surprisingly divergent, with the lowest known sequence identity (60%) in any single fungal species. Comparative analysis showed that beta-tubulin 1 and the intron distribution within the tubb1 gene resemble the other beta-tubulins. beta-Tubulin 2, in contrast, is the most divergent fully described fungal beta-tubulin and the gene contains at least 21 introns, which is the largest amount known for any beta-tubulin gene. Despite this divergence, both genes are constitutively expressed in the functional compartments of the mycorrhizosphere and in pure cultures. Transcription of tubb1 is about 2.4 times higher than that of tubb2; and this difference is also seen at the translation level. Evidence suggested that phosphorylation may be the main post-translational modification of both beta-tubulins. The putative GTP-binding site residues of beta-tubulin 1 match crystallised pig beta-tubulin residues, while five of the nine differences in beta-tubulin 2 match the pig alpha-tubulin GTP-site, suggesting the presence of adaptive sequence evolution. In a Bayesian analysis, beta-tubulin 1 joins the other basidiomycete sequences, while beta-tubulin 2 loosely associates with the group of divergent ascomycete sequences without any clear relative among the known full-length fungal beta-tubulin sequences.
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Suillus bovinus glutamine synthetase gene organization transcription and enzyme activities in the scots pine mycorrhizosphere developed on forest humus
New Phytologist, 2004Co-Authors: Jarmo T. Juuti, Sari Timonen, Sanna Jokela, Lars Paulin, Robin SenAbstract:Summary • Glutamine synthetase (GS) expression and activity is of central importance for cellular ammonium assimilation and recycling. Thus, a full characterization of this enzyme at the molecular level is of critical importance for a better understanding of nitrogen (N) assimilation in the mycorrhizal symbiosis. • Genomic and cDNA libraries of Suillus bovinus were constructed to isolate the GS gene, glnA, and corresponding cDNAs. The transcription initiation site was identified and transcription and enzyme activities were characterized in pure culture mycelium and mycorrhiza, and extramatrical mycelium samples harvested from Scots pine–Suillus bovinus microcosms grown on forest humus. • Pure culture mycelium, mycorrhiza and extramatrical mycelium all exhibited equivalent levels of GS transcription, translation and enzyme activities. However, levels of transcription and enzyme activity did not correlate as a large majority of detectable transcripts showed specific 5′-end truncation. • Our data suggest that GS is constitutively expressed and not directly affected by environmental conditions of the symbiotic N uptake. Any changes in the intracellular ammonium level are most likely handled by regulatory flexibility of GS at enzyme level.
Robin Sen - One of the best experts on this subject based on the ideXlab platform.
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Suillus bovinus glutamine synthetase gene organization transcription and enzyme activities in the scots pine mycorrhizosphere developed on forest humus
New Phytologist, 2004Co-Authors: Jarmo T. Juuti, Sari Timonen, Sanna Jokela, Lars Paulin, Robin SenAbstract:Summary • Glutamine synthetase (GS) expression and activity is of central importance for cellular ammonium assimilation and recycling. Thus, a full characterization of this enzyme at the molecular level is of critical importance for a better understanding of nitrogen (N) assimilation in the mycorrhizal symbiosis. • Genomic and cDNA libraries of Suillus bovinus were constructed to isolate the GS gene, glnA, and corresponding cDNAs. The transcription initiation site was identified and transcription and enzyme activities were characterized in pure culture mycelium and mycorrhiza, and extramatrical mycelium samples harvested from Scots pine–Suillus bovinus microcosms grown on forest humus. • Pure culture mycelium, mycorrhiza and extramatrical mycelium all exhibited equivalent levels of GS transcription, translation and enzyme activities. However, levels of transcription and enzyme activity did not correlate as a large majority of detectable transcripts showed specific 5′-end truncation. • Our data suggest that GS is constitutively expressed and not directly affected by environmental conditions of the symbiotic N uptake. Any changes in the intracellular ammonium level are most likely handled by regulatory flexibility of GS at enzyme level.
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its probe development for specific detection of rhizoctonia spp and Suillus bovinus based on southern blot and liquid hybridization fragment length polymorphism
Fungal Biology, 2003Co-Authors: Henrietta Gronberg, Lars Paulin, Robin SenAbstract:Development of specific DNA probes targeting rDNA internal transcribed spacer (ITS-1 or -2) sequences is described for the detection of strains representing uninucleate and binucleate Rhizoctonia spp. and Suillus bovinus. Discriminatory taxon/species-specific target sequences were identified following full length ITS sequence alignment of the test fungal sequences and those of other root associated pathogenic or mycorrhizal fungi. Both long (124–151 bp) and shorter (20–25 bp) probes were generated for assessment in Southern dot blot and liquid hybridization ITS capture-fragment length polymorphism assays. Fungal genomic DNA was presented as the target in dot blot protocols using the longer DIG (digoxigenin) labelled probes whilst the shorter 3′ biotin-labelled oligonucleotide probes were hybridized to PCR amplified full length ITS (ITS1-5.8S-ITS2) in both dot blot and liquid hybridization assays. The optimal hybridization temperatures for dot blot detection also produced maximal target specific signals in the liquid hybridization protocol. The latter protocol was found to be more discriminatory as target fungi were detected on the basis of combined probe hybridization-ITS capture and 5′ Cy-5 labelled ITS length polymorphism analysis (±5 bp) following denaturing sequencing gel electrophoresis in a ALFexpress DNA sequencer.
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microbial biofilms and catabolic plasmid harbouring degradative fluorescent pseudomonads in scots pine mycorrhizospheres developed on petroleum contaminated soil
FEMS Microbiology Ecology, 1998Co-Authors: Inga Sarand, Kielo Haahtela, Sari Timonen, Eevaliisa Nurmiaholassila, Teija Koivula, Martin Romantschuk, Robin SenAbstract:Abstract Cellular interactions and catabolic activities of mycorrhizal root associated non-sporulating bacteria were investigated in a simplified phytoremediation simulation involving a woody plant species. Mycorrhizal Scots pine ( Pinus sylvestris ) seedlings pre-colonised by Suillus bovinus or Paxillus involutus were grown in forest humus containing microcosms amended with petroleum hydrocarbon (PHC) contaminated soil. Fungal hyphae of both species, emanating from mycorrhizal roots, colonised the PHC contaminated soil over a 16-week period and dense long-lived patches of S. bovinus hyphae formed on the PHC contaminated soil. Transmission electron microscopy revealed a microbial biofilm at the PHC soil-fungal interface composed of differentiated pseudoparenchymous patch hyphae supporting a morphologically diverse bacterial population. Certain non-sporulating bacterial isolates closely associated with the S. bovinus patch hyphae or P. involutus `web' hyphae from the PHC soil harboured similar sized mega-plasmids (approx. 150 kb). Isolates of Pseudomonas fluorescens from the `patch' mycorrhizospheres represented different biovars, displayed similar REP-PCR genomic fingerprints, grew on e.g. m -toluate and m -xylene as sole carbon sources, cleaved catechol, and harboured plasmid-borne catabolic marker genes, xylE and xylMA , involved in degradation of mono-aromatics. The plasmids were transmissible in vitro, and Pseudomonas putida transconjugants retained a similar catabolic profile. The identification of microbial biofilms containing catabolic bacteria in the external mycorrhizosphere is discussed in relation to both phytoremediation mechanisms and normal efficient nutrient mobilisation from highly lignin-rich forest soils.
Jarkko Lahdensalo - One of the best experts on this subject based on the ideXlab platform.
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Two phylogenetically highly distinct β-tubulin genes of the basidiomycete Suillus bovinus
Current Genetics, 2005Co-Authors: Jarmo T. Juuti, Mika T. Tarkka, Sanna Jokela, Lars Paulin, Jarkko LahdensaloAbstract:Genes tubb1 and tubb2 which encode β-tubulins 1 and 2, respectively, were characterised from the ectomycorrhizal basidiomycete Suillus bovinus . The two β-tubulins are surprisingly divergent, with the lowest known sequence identity (60%) in any single fungal species. Comparative analysis showed that β-tubulin 1 and the intron distribution within the tubb1 gene resemble the other β-tubulins. β-Tubulin 2, in contrast, is the most divergent fully described fungal β-tubulin and the gene contains at least 21 introns, which is the largest amount known for any β-tubulin gene. Despite this divergence, both genes are constitutively expressed in the functional compartments of the mycorrhizosphere and in pure cultures. Transcription of tubb1 is about 2.4 times higher than that of tubb2 ; and this difference is also seen at the translation level. Evidence suggested that phosphorylation may be the main post-translational modification of both β-tubulins. The putative GTP-binding site residues of β-tubulin 1 match crystallised pig β-tubulin residues, while five of the nine differences in β-tubulin 2 match the pig α-tubulin GTP-site, suggesting the presence of adaptive sequence evolution. In a Bayesian analysis, β-tubulin 1 joins the other basidiomycete sequences, while β-tubulin 2 loosely associates with the group of divergent ascomycete sequences without any clear relative among the known full-length fungal β-tubulin sequences.
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two phylogenetically highly distinct β tubulin genes of the basidiomycete Suillus bovinus
Current Genetics, 2005Co-Authors: Jarmo T. Juuti, Mika T. Tarkka, Sanna Jokela, Lars Paulin, Jarkko LahdensaloAbstract:Genes tubb1 and tubb2 which encode beta-tubulins 1 and 2, respectively, were characterised from the ectomycorrhizal basidiomycete Suillus bovinus. The two beta-tubulins are surprisingly divergent, with the lowest known sequence identity (60%) in any single fungal species. Comparative analysis showed that beta-tubulin 1 and the intron distribution within the tubb1 gene resemble the other beta-tubulins. beta-Tubulin 2, in contrast, is the most divergent fully described fungal beta-tubulin and the gene contains at least 21 introns, which is the largest amount known for any beta-tubulin gene. Despite this divergence, both genes are constitutively expressed in the functional compartments of the mycorrhizosphere and in pure cultures. Transcription of tubb1 is about 2.4 times higher than that of tubb2; and this difference is also seen at the translation level. Evidence suggested that phosphorylation may be the main post-translational modification of both beta-tubulins. The putative GTP-binding site residues of beta-tubulin 1 match crystallised pig beta-tubulin residues, while five of the nine differences in beta-tubulin 2 match the pig alpha-tubulin GTP-site, suggesting the presence of adaptive sequence evolution. In a Bayesian analysis, beta-tubulin 1 joins the other basidiomycete sequences, while beta-tubulin 2 loosely associates with the group of divergent ascomycete sequences without any clear relative among the known full-length fungal beta-tubulin sequences.
