The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Claude Lemieux - One of the best experts on this subject based on the ideXlab platform.
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Gene partitioning patterns of the Scherffelia, Tetraselmis and other chlorophyte chloroplast genomes.
2016Co-Authors: Monique Turmel, Christian Otis, J.‐c. De Cambiaire, Claude LemieuxAbstract:For each genome, one copy of the IR (thick vertical lines) and the entire SSC region are represented, but only the portion of the LSC region in the vicinity of the IR is displayed. The five genes composing the rDNA operon are highlighted in light green. The color assigned to each of the remaining genes is dependent upon the position of the corresponding gene relative to the rDNA operon in the cpDNA of the streptophyte alga Mesostigma viride, a genome displaying an ancestral gene partitioning pattern [56]. The genes highlighted in blue are found within or near the SSC region in this streptophyte genome (downstream of the rDNA operon), whereas those highlighted in light orange are found within or near the LSC region (upstream of the rDNA operon). The dark orange boxes denote the genes of LSC origin that have been acquired by the IRs of core chlorophytes (pedinophyceans, chlorodendrophyceans and core trebouxiophyceans). Note that, to simplify the comparison of gene order, some genomes are represented in their alternative isomeric form as compared to that used for the genome sequence deposited in GenBank.
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Intron insertion sites in the mitochondrial rnl genes of selected green algae.
2013Co-Authors: Jean-françois Pombert, Monique Turmel, Christian Otis, Claude LemieuxAbstract:Cis- and trans-spliced introns are shown by triangles and broken triangles, respectively. When present, intronic ORFs are shown by filled triangles. Intron insertion sites are given relative to the E. coli 23S rRNA; for each site, the position corresponding to the nucleotide immediately preceding the intron is reported. Accession numbers for the rnl sequences represented are as follows: Prasinoderma coloniale, KF387569; Monomastix sp, KF060939; Nephroselmis olivacea, NC_008239; Oltmannsiellopsis viridis, NC_008256; Pseudendoclonium akinetum, NC_005926; Chlamydomonas eugametos, NC_001872; Dunaliella salina, NC_012930; Mesostigma viride, NC_008240; and Chara vulgaris, NC_005255.
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Previously reported trans-spliced group I introns in cox1 that have cis-spliced relatives containing an ORF at cognate sites.
2013Co-Authors: Jean-françois Pombert, Monique Turmel, Christian Otis, Claude LemieuxAbstract:aWhen multiple introns are present, a number following the taxon name designates the intron number.bEach of the three intron insertion sites is given relative to the cox1 gene of Mesostigma viride; for each site, the position immediately preceding the intron is given.
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An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus
BMC Genomics, 2007Co-Authors: Monique Turmel, Christian Otis, Claude LemieuxAbstract:Background The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate Mesostigma viride (Mesostigmatales) and the sarcinoid Chlorokybus atmophyticus (Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of Chlorokybus and compared this genome sequence with those of three other charophycean green algae and the bryophytes Marchantia polymorpha and Physcomitrella patens . Results The Chlorokybus genome differs radically from its 42,424-bp Mesostigma counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include nad10 and trnL (gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the Chlorokybus genome shares with its Chara , Chaetosphaeridium and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of Mesostigma , due to analytical problems arising from accelerated sequence evolution in this lineage. Conclusion The Chlorokybus and Mesostigma mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.
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An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus
BMC genomics, 2007Co-Authors: Monique Turmel, Christian Otis, Claude LemieuxAbstract:The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate Mesostigma viride (Mesostigmatales) and the sarcinoid Chlorokybus atmophyticus (Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of Chlorokybus and compared this genome sequence with those of three other charophycean green algae and the bryophytes Marchantia polymorpha and Physcomitrella patens. The Chlorokybus genome differs radically from its 42,424-bp Mesostigma counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include nad10 and trnL(gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the Chlorokybus genome shares with its Chara, Chaetosphaeridium and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of Mesostigma, due to analytical problems arising from accelerated sequence evolution in this lineage. The Chlorokybus and Mesostigma mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.
Monique Turmel - One of the best experts on this subject based on the ideXlab platform.
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Gene partitioning patterns of the Scherffelia, Tetraselmis and other chlorophyte chloroplast genomes.
2016Co-Authors: Monique Turmel, Christian Otis, J.‐c. De Cambiaire, Claude LemieuxAbstract:For each genome, one copy of the IR (thick vertical lines) and the entire SSC region are represented, but only the portion of the LSC region in the vicinity of the IR is displayed. The five genes composing the rDNA operon are highlighted in light green. The color assigned to each of the remaining genes is dependent upon the position of the corresponding gene relative to the rDNA operon in the cpDNA of the streptophyte alga Mesostigma viride, a genome displaying an ancestral gene partitioning pattern [56]. The genes highlighted in blue are found within or near the SSC region in this streptophyte genome (downstream of the rDNA operon), whereas those highlighted in light orange are found within or near the LSC region (upstream of the rDNA operon). The dark orange boxes denote the genes of LSC origin that have been acquired by the IRs of core chlorophytes (pedinophyceans, chlorodendrophyceans and core trebouxiophyceans). Note that, to simplify the comparison of gene order, some genomes are represented in their alternative isomeric form as compared to that used for the genome sequence deposited in GenBank.
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Intron insertion sites in the mitochondrial rnl genes of selected green algae.
2013Co-Authors: Jean-françois Pombert, Monique Turmel, Christian Otis, Claude LemieuxAbstract:Cis- and trans-spliced introns are shown by triangles and broken triangles, respectively. When present, intronic ORFs are shown by filled triangles. Intron insertion sites are given relative to the E. coli 23S rRNA; for each site, the position corresponding to the nucleotide immediately preceding the intron is reported. Accession numbers for the rnl sequences represented are as follows: Prasinoderma coloniale, KF387569; Monomastix sp, KF060939; Nephroselmis olivacea, NC_008239; Oltmannsiellopsis viridis, NC_008256; Pseudendoclonium akinetum, NC_005926; Chlamydomonas eugametos, NC_001872; Dunaliella salina, NC_012930; Mesostigma viride, NC_008240; and Chara vulgaris, NC_005255.
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Previously reported trans-spliced group I introns in cox1 that have cis-spliced relatives containing an ORF at cognate sites.
2013Co-Authors: Jean-françois Pombert, Monique Turmel, Christian Otis, Claude LemieuxAbstract:aWhen multiple introns are present, a number following the taxon name designates the intron number.bEach of the three intron insertion sites is given relative to the cox1 gene of Mesostigma viride; for each site, the position immediately preceding the intron is given.
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An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus
BMC Genomics, 2007Co-Authors: Monique Turmel, Christian Otis, Claude LemieuxAbstract:Background The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate Mesostigma viride (Mesostigmatales) and the sarcinoid Chlorokybus atmophyticus (Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of Chlorokybus and compared this genome sequence with those of three other charophycean green algae and the bryophytes Marchantia polymorpha and Physcomitrella patens . Results The Chlorokybus genome differs radically from its 42,424-bp Mesostigma counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include nad10 and trnL (gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the Chlorokybus genome shares with its Chara , Chaetosphaeridium and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of Mesostigma , due to analytical problems arising from accelerated sequence evolution in this lineage. Conclusion The Chlorokybus and Mesostigma mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.
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An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus
BMC genomics, 2007Co-Authors: Monique Turmel, Christian Otis, Claude LemieuxAbstract:The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate Mesostigma viride (Mesostigmatales) and the sarcinoid Chlorokybus atmophyticus (Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of Chlorokybus and compared this genome sequence with those of three other charophycean green algae and the bryophytes Marchantia polymorpha and Physcomitrella patens. The Chlorokybus genome differs radically from its 42,424-bp Mesostigma counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include nad10 and trnL(gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the Chlorokybus genome shares with its Chara, Chaetosphaeridium and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of Mesostigma, due to analytical problems arising from accelerated sequence evolution in this lineage. The Chlorokybus and Mesostigma mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.
Christian Otis - One of the best experts on this subject based on the ideXlab platform.
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Gene partitioning patterns of the Scherffelia, Tetraselmis and other chlorophyte chloroplast genomes.
2016Co-Authors: Monique Turmel, Christian Otis, J.‐c. De Cambiaire, Claude LemieuxAbstract:For each genome, one copy of the IR (thick vertical lines) and the entire SSC region are represented, but only the portion of the LSC region in the vicinity of the IR is displayed. The five genes composing the rDNA operon are highlighted in light green. The color assigned to each of the remaining genes is dependent upon the position of the corresponding gene relative to the rDNA operon in the cpDNA of the streptophyte alga Mesostigma viride, a genome displaying an ancestral gene partitioning pattern [56]. The genes highlighted in blue are found within or near the SSC region in this streptophyte genome (downstream of the rDNA operon), whereas those highlighted in light orange are found within or near the LSC region (upstream of the rDNA operon). The dark orange boxes denote the genes of LSC origin that have been acquired by the IRs of core chlorophytes (pedinophyceans, chlorodendrophyceans and core trebouxiophyceans). Note that, to simplify the comparison of gene order, some genomes are represented in their alternative isomeric form as compared to that used for the genome sequence deposited in GenBank.
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Intron insertion sites in the mitochondrial rnl genes of selected green algae.
2013Co-Authors: Jean-françois Pombert, Monique Turmel, Christian Otis, Claude LemieuxAbstract:Cis- and trans-spliced introns are shown by triangles and broken triangles, respectively. When present, intronic ORFs are shown by filled triangles. Intron insertion sites are given relative to the E. coli 23S rRNA; for each site, the position corresponding to the nucleotide immediately preceding the intron is reported. Accession numbers for the rnl sequences represented are as follows: Prasinoderma coloniale, KF387569; Monomastix sp, KF060939; Nephroselmis olivacea, NC_008239; Oltmannsiellopsis viridis, NC_008256; Pseudendoclonium akinetum, NC_005926; Chlamydomonas eugametos, NC_001872; Dunaliella salina, NC_012930; Mesostigma viride, NC_008240; and Chara vulgaris, NC_005255.
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Previously reported trans-spliced group I introns in cox1 that have cis-spliced relatives containing an ORF at cognate sites.
2013Co-Authors: Jean-françois Pombert, Monique Turmel, Christian Otis, Claude LemieuxAbstract:aWhen multiple introns are present, a number following the taxon name designates the intron number.bEach of the three intron insertion sites is given relative to the cox1 gene of Mesostigma viride; for each site, the position immediately preceding the intron is given.
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An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus
BMC Genomics, 2007Co-Authors: Monique Turmel, Christian Otis, Claude LemieuxAbstract:Background The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate Mesostigma viride (Mesostigmatales) and the sarcinoid Chlorokybus atmophyticus (Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of Chlorokybus and compared this genome sequence with those of three other charophycean green algae and the bryophytes Marchantia polymorpha and Physcomitrella patens . Results The Chlorokybus genome differs radically from its 42,424-bp Mesostigma counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include nad10 and trnL (gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the Chlorokybus genome shares with its Chara , Chaetosphaeridium and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of Mesostigma , due to analytical problems arising from accelerated sequence evolution in this lineage. Conclusion The Chlorokybus and Mesostigma mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.
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An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus
BMC genomics, 2007Co-Authors: Monique Turmel, Christian Otis, Claude LemieuxAbstract:The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate Mesostigma viride (Mesostigmatales) and the sarcinoid Chlorokybus atmophyticus (Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of Chlorokybus and compared this genome sequence with those of three other charophycean green algae and the bryophytes Marchantia polymorpha and Physcomitrella patens. The Chlorokybus genome differs radically from its 42,424-bp Mesostigma counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include nad10 and trnL(gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the Chlorokybus genome shares with its Chara, Chaetosphaeridium and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of Mesostigma, due to analytical problems arising from accelerated sequence evolution in this lineage. The Chlorokybus and Mesostigma mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.
Burkhard Becker - One of the best experts on this subject based on the ideXlab platform.
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the gapa b gene duplication marks the origin of streptophyta charophytes and land plants
Molecular Biology and Evolution, 2006Co-Authors: Jorn Petersen, Burkhard Becker, Rene Teich, Rudiger Cerff, Henner BrinkmannAbstract:Independent evidence from morphological, ultrastructural, biochemical, and molecular data have shown that land plants originated from charophycean green algae. However, the branching order within charophytes is still unresolved, and contradictory phylogenies about, for example,the position of the unicellular green alga Mesostigma viride are difficult to reconcile. A comparison of nuclear-encoded Calvin cycle glyceraldehyde-3-phosphate dehydrogenases (GAPDH) indicates that a crucial duplication of the GapA gene occurred early in land plant evolution. The duplicate called GapB acquired a characteristic carboxy-terminal extension (CTE) from the general regulator of the Calvin cycle CP12. This CTE is responsible for thioredoxin-dependent light/dark regulation. In this work, we established GapA, GapB, and CP12 sequences from bryophytes, all orders of charophyte as well as chlorophyte green algae, and the glaucophyte Cyanophora paradoxa. Comprehensive phylogenetic analyses of all available plastid GAPDH sequences suggest that glaucophytes and green plants are sister lineages and support a positioning of Mesostigma basal to all charophycean algae. The exclusive presence of GapB in terrestrial plants, charophytes, and Mesostigma dates the GapA/B gene duplication to the common ancestor of Streptophyta. The conspicuously high degree of GapB sequence conservation suggests an important metabolic role of the newly gained regulatory function. Because the GapB-mediated protein aggregation most likely ensures the complete blockage of the Calvin cycle at night, we propose that this mechanism is also crucial for efficient starch mobilization. This innovation may be one prerequisite for the development of storage tissues in land plants.
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EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): Implications for the evolution of green plants (Viridiplantae)
BMC Plant Biology, 2006Co-Authors: Andreas Simon, Marius Felder, Michael Melkonian, Gernot Glöckner, Burkhard BeckerAbstract:Background The Viridiplantae (land plants and green algae) consist of two monophyletic lineages, the Chlorophyta and the Streptophyta. The Streptophyta include all embryophytes and a small but diverse group of freshwater algae traditionally known as the Charophyceae (e.g. Charales, Coleochaete and the Zygnematales). The only flagellate currently included in the Streptophyta is Mesostigma viride Lauterborn. To gain insight into the genome evolution in streptophytes, we have sequenced 10,395 ESTs from Mesostigma representing 3,300 independent contigs and compared the ESTs of Mesostigma with available plant genomes ( Arabidopsis, Oryza , Chlamydomonas ), with ESTs from the bryophyte Physcomitrella , the genome of the rhodophyte Cyanidioschyzon , the ESTs from the rhodophyte Porphyra , and the genome of the diatom Thalassiosira . Results The number of expressed genes shared by Mesostigma with the embryophytes (90.3 % of the expressed genes showing similarity to known proteins) is higher than with Chlamydomonas (76.1 %). In general, cytosolic metabolic pathways, and proteins involved in vesicular transport, transcription, regulation, DNA-structure and replication, cell cycle control, and RNA-metabolism are more conserved between Mesostigma and the embryophytes than between Mesostigma and Chlamydomonas . However, plastidic and mitochondrial metabolic pathways, cytoskeletal proteins and proteins involved in protein folding are more conserved between Mesostigma and Chlamydomonas than between Mesostigma and the embryophytes. Conclusion Our EST-analysis of Mesostigma supports the notion that this organism should be a suitable unicellular model for the last flagellate common ancestor of the streptophytes. Mesostigma shares more genes with the embryophytes than with the chlorophyte Chlamydomonas reinhardtii , although both organisms are flagellate unicells. Thus, it seems likely that several major physiological changes (e.g. in the regulation of photosynthesis and photorespiration) took place early during the evolution of streptophytes, i.e. before the transition to land.
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BMC Plant Biology BioMed Central
2005Co-Authors: Andreas Simon, Burkhard Becker, Marius Felder, Michael Melkonian, Gernot GlöcknerAbstract:Research article EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): Implications for the evolution of green plants (Viridiplantae
Michael Melkonian - One of the best experts on this subject based on the ideXlab platform.
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EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): Implications for the evolution of green plants (Viridiplantae)
BMC Plant Biology, 2006Co-Authors: Andreas Simon, Marius Felder, Gernot Glöckner, Michael MelkonianAbstract:Background The Viridiplantae (land plants and green algae) consist of two monophyletic lineages, the Chlorophyta and the Streptophyta. The Streptophyta include all embryophytes and a small but diverse group of freshwater algae traditionally known as the Charophyceae (e.g. Charales, Coleochaete and the Zygnematales). The only flagellate currently included in the Streptophyta is Mesostigma viride Lauterborn. To gain insight into the genome evolution in streptophytes, we have sequenced 10,395 ESTs from Mesostigma representing 3,300 independent contigs and compared the ESTs of Mesostigma with available plant genomes (Arabidopsis, Oryza, Chlamydomonas), with ESTs from the bryophyte Physcomitrella, the genome of the rhodophyte Cyanidioschyzon, the ESTs from the rhodophyte Porphyra, and the genome of the diatom Thalassiosira.
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EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): Implications for the evolution of green plants (Viridiplantae)
BMC Plant Biology, 2006Co-Authors: Andreas Simon, Marius Felder, Michael Melkonian, Gernot Glöckner, Burkhard BeckerAbstract:Background The Viridiplantae (land plants and green algae) consist of two monophyletic lineages, the Chlorophyta and the Streptophyta. The Streptophyta include all embryophytes and a small but diverse group of freshwater algae traditionally known as the Charophyceae (e.g. Charales, Coleochaete and the Zygnematales). The only flagellate currently included in the Streptophyta is Mesostigma viride Lauterborn. To gain insight into the genome evolution in streptophytes, we have sequenced 10,395 ESTs from Mesostigma representing 3,300 independent contigs and compared the ESTs of Mesostigma with available plant genomes ( Arabidopsis, Oryza , Chlamydomonas ), with ESTs from the bryophyte Physcomitrella , the genome of the rhodophyte Cyanidioschyzon , the ESTs from the rhodophyte Porphyra , and the genome of the diatom Thalassiosira . Results The number of expressed genes shared by Mesostigma with the embryophytes (90.3 % of the expressed genes showing similarity to known proteins) is higher than with Chlamydomonas (76.1 %). In general, cytosolic metabolic pathways, and proteins involved in vesicular transport, transcription, regulation, DNA-structure and replication, cell cycle control, and RNA-metabolism are more conserved between Mesostigma and the embryophytes than between Mesostigma and Chlamydomonas . However, plastidic and mitochondrial metabolic pathways, cytoskeletal proteins and proteins involved in protein folding are more conserved between Mesostigma and Chlamydomonas than between Mesostigma and the embryophytes. Conclusion Our EST-analysis of Mesostigma supports the notion that this organism should be a suitable unicellular model for the last flagellate common ancestor of the streptophytes. Mesostigma shares more genes with the embryophytes than with the chlorophyte Chlamydomonas reinhardtii , although both organisms are flagellate unicells. Thus, it seems likely that several major physiological changes (e.g. in the regulation of photosynthesis and photorespiration) took place early during the evolution of streptophytes, i.e. before the transition to land.
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BMC Plant Biology BioMed Central
2005Co-Authors: Andreas Simon, Burkhard Becker, Marius Felder, Michael Melkonian, Gernot GlöcknerAbstract:Research article EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): Implications for the evolution of green plants (Viridiplantae