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Peter Szovenyi - One of the best experts on this subject based on the ideXlab platform.
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an agrobacterium mediated stable transformation technique for the Hornwort model anthoceros agrestis
New Phytologist, 2021Co-Authors: Eftychios Frangedakis, Manuel Waller, Tomoaki Nishiyama, Hirokazu Tsukaya, Yuling Yue, Michelle Tjahjadi, Andika Gunadi, Joyce Van Eck, Peter SzovenyiAbstract:Despite their key phylogenetic position and their unique biology, Hornworts have been widely overlooked. Until recently there was no Hornwort model species amenable to systematic experimental investigation. Anthoceros agrestis has been proposed as the model species to study Hornwort biology. We have developed an Agrobacterium-mediated method for the stable transformation of A. agrestis, a Hornwort model species for which a genetic manipulation technique was not yet available. High transformation efficiency was achieved by using thallus tissue grown under low light conditions. We generated a total of 274 transgenic A. agrestis lines expressing the β-glucuronidase (GUS), cyan, green, and yellow fluorescent proteins under control of the CaMV 35S promoter and several endogenous promoters. Nuclear and plasma membrane localization with multiple color fluorescent proteins was also confirmed. The transformation technique described here should pave the way for detailed molecular and genetic studies of Hornwort biology, providing much needed insight into the molecular mechanisms underlying symbiosis, carbon-concentrating mechanism, RNA editing and land plant evolution in general.
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a simple agrobacterium mediated stable transformation technique for the Hornwort model anthoceros agrestis
bioRxiv, 2021Co-Authors: Eftychios Frangedakis, Manuel Waller, Tomoaki Nishiyama, Hirokazu Tsukaya, Yuling Yue, Michelle Tjahjadi, Andika Gunadi, Joyce Van Eck, Peter SzovenyiAbstract:We have developed a simple Agrobacterium-mediated method for the stable transformation of the Hornwort Anthoceros agrestis, the fifth bryophyte species for which a genetic manipulation technique becomes available. High transformation efficiency was achieved by using thallus tissue grown under low-light conditions. We generated a total of 216 transgenic A. agrestis lines expressing the β-Glucuronidase (GUS), cyan, green, and yellow fluorescent proteins under the control of the CaMV 35S promoter and several endogenous promoters. Nuclear and plasma membrane localization with multiple color fluorescent proteins was also confirmed. The transformation technique described here should pave the way for detailed molecular and genetic studies of Hornwort biology, providing much needed insight into the molecular mechanisms underlying symbiosis, carbon-concentrating mechanism, RNA editing, and land plant evolution in general.
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towards a plant model for enigmatic u to c rna editing the organelle genomes transcriptomes editomes and candidate rna editing factors in the Hornwort anthoceros agrestis
New Phytologist, 2020Co-Authors: Philipp Gerke, Henning Lenz, Peter Szovenyi, Anna Neubauer, Bernard Gutmann, Rose Mcdowell, Ian Small, Mareike SchallenbergrudingerAbstract:Hornworts are crucial to understand the phylogeny of early land plants. The emergence of ‘reverse’ U‐to‐C RNA editing accompanying the widespread C‐to‐U RNA editing in plant chloroplasts and mitochondria may be a molecular synapomorphy of a Hornwort–tracheophyte clade. C‐to‐U RNA editing is well understood after identification of many editing factors in models like Arabidopsis thaliana and Physcomitrella patens, but there is no plant model yet to investigate U‐to‐C RNA editing. The Hornwort Anthoceros agrestis is now emerging as such a model system. We report on the assembly and analyses of the A. agrestis chloroplast and mitochondrial genomes, their transcriptomes and editomes, and a large nuclear gene family encoding pentatricopeptide repeat (PPR) proteins likely acting as RNA editing factors. Both organelles in A. agrestis feature high amounts of RNA editing, with altogether > 1100 sites of C‐to‐U and 1300 sites of U‐to‐C editing. The nuclear genome reveals > 1400 genes for PPR proteins with variable carboxyterminal DYW domains. We observe significant variants of the ‘classic’ DYW domain, in the meantime confirmed as the cytidine deaminase for C‐to‐U editing, and discuss the first attractive candidates for reverse editing factors given their excellent matches to U‐to‐C editing targets according to the PPR‐RNA binding code.
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Establishment of Anthoceros agrestis as a model species for studying the biology of Hornworts
BMC Plant Biology, 2015Co-Authors: Peter Szovenyi, Dietmar Quandt, Eftychios Frangedakis, Mariana Ricca, Susann Wicke, Jane A LangdaleAbstract:Background Plants colonized terrestrial environments approximately 480 million years ago and have contributed significantly to the diversification of life on Earth. Phylogenetic analyses position a subset of charophyte algae as the sister group to land plants, and distinguish two land plant groups that diverged around 450 million years ago – the bryophytes and the vascular plants. Relationships between liverworts, mosses Hornworts and vascular plants have proven difficult to resolve, and as such it is not clear which bryophyte lineage is the sister group to all other land plants and which is the sister to vascular plants. The lack of comparative molecular studies in representatives of all three lineages exacerbates this uncertainty. Such comparisons can be made between mosses and liverworts because representative model organisms are well established in these two bryophyte lineages. To date, however, a model Hornwort species has not been available. Results Here we report the establishment of Anthoceros agrestis as a model Hornwort species for laboratory experiments. Axenic culture conditions for maintenance and vegetative propagation have been determined, and treatments for the induction of sexual reproduction and sporophyte development have been established. In addition, protocols have been developed for the extraction of DNA and RNA that is of a quality suitable for molecular analyses. Analysis of haploid-derived genome sequence data of two A. agrestis isolates revealed single nucleotide polymorphisms at multiple loci, and thus these two strains are suitable starting material for classical genetic and mapping experiments. Conclusions Methods and resources have been developed to enable A. agrestis to be used as a model species for developmental, molecular, genomic, and genetic studies. This advance provides an unprecedented opportunity to investigate the biology of Hornworts.
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establishment of anthoceros agrestis as a model species for studying the biology of Hornworts
BMC Plant Biology, 2015Co-Authors: Peter Szovenyi, Dietmar Quandt, Eftychios Frangedakis, Mariana Ricca, Susann Wicke, Jane A LangdaleAbstract:Plants colonized terrestrial environments approximately 480 million years ago and have contributed significantly to the diversification of life on Earth. Phylogenetic analyses position a subset of charophyte algae as the sister group to land plants, and distinguish two land plant groups that diverged around 450 million years ago – the bryophytes and the vascular plants. Relationships between liverworts, mosses Hornworts and vascular plants have proven difficult to resolve, and as such it is not clear which bryophyte lineage is the sister group to all other land plants and which is the sister to vascular plants. The lack of comparative molecular studies in representatives of all three lineages exacerbates this uncertainty. Such comparisons can be made between mosses and liverworts because representative model organisms are well established in these two bryophyte lineages. To date, however, a model Hornwort species has not been available. Here we report the establishment of Anthoceros agrestis as a model Hornwort species for laboratory experiments. Axenic culture conditions for maintenance and vegetative propagation have been determined, and treatments for the induction of sexual reproduction and sporophyte development have been established. In addition, protocols have been developed for the extraction of DNA and RNA that is of a quality suitable for molecular analyses. Analysis of haploid-derived genome sequence data of two A. agrestis isolates revealed single nucleotide polymorphisms at multiple loci, and thus these two strains are suitable starting material for classical genetic and mapping experiments. Methods and resources have been developed to enable A. agrestis to be used as a model species for developmental, molecular, genomic, and genetic studies. This advance provides an unprecedented opportunity to investigate the biology of Hornworts.
Juan Carlos Villarreal - One of the best experts on this subject based on the ideXlab platform.
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organellomic data sets confirm a cryptic consensus on unrooted land plant relationships and provide new insights into bryophyte molecular evolution
American Journal of Botany, 2020Co-Authors: David Bell, Carl J Rothfels, Qianshi Lin, Wesley K Gerelle, Steve Joya, Ying Chang, Nathan Z Taylor, Anders Larsson, Juan Carlos VillarrealAbstract:Premise Phylogenetic trees of bryophytes provide important evolutionary context for land plants. However, published inferences of overall embryophyte relationships vary considerably. We performed phylogenomic analyses of bryophytes and relatives using both mitochondrial and plastid gene sets, and investigated bryophyte plastome evolution. Methods We employed diverse likelihood‐based analyses to infer large‐scale bryophyte phylogeny for mitochondrial and plastid data sets. We tested for changes in purifying selection in plastid genes of a mycoheterotrophic liverwort (Aneura mirabilis) and a putatively mycoheterotrophic moss (Buxbaumia), and compared 15 bryophyte plastomes for major structural rearrangements. Results Overall land‐plant relationships conflict across analyses, generally weakly. However, an underlying (unrooted) four‐taxon tree is consistent across most analyses and published studies. Despite gene coverage patchiness, relationships within mosses, liverworts, and Hornworts are largely congruent with previous studies, with plastid results generally better supported. Exclusion of RNA edit sites restores cases of unexpected non‐monophyly to monophyly for Takakia and two Hornwort genera. Relaxed purifying selection affects multiple plastid genes in mycoheterotrophic Aneura but not Buxbaumia. Plastid genome structure is nearly invariant across bryophytes, but the tufA locus, presumed lost in embryophytes, is unexpectedly retained in several mosses. Conclusions A common unrooted tree underlies embryophyte phylogeny, [(liverworts, mosses), (Hornworts, vascular plants)]; rooting inconsistency across studies likely reflects substantial distance to algal outgroups. Analyses combining genomic and transcriptomic data may be misled locally for heavily RNA‐edited taxa. The Buxbaumia plastome lacks hallmarks of relaxed selection found in mycoheterotrophic Aneura. Autotrophic bryophyte plastomes, including Buxbaumia, hardly vary in overall structure.
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a synthesis of Hornwort diversity patterns causes and future work
Phytotaxa, 2014Co-Authors: Juan Carlos Villarreal, Anders Hagborg, Lars Söderström, D. Christine Cargill, Karen S RenzagliaAbstract:Hornworts are the least species-rich bryophyte group, with around 200-250 species worldwide. Despite their low species numbers, Hornworts represent a key group for understanding the evolution of plant form because the best-sampled current phylogenies place them as sister to the tracheophytes. Despite their low taxonomic diversity, the group has not been monographed worldwide. There are few well-documented Hornwort floras for temperate or tropical areas. Moreover, no species level phylogenies or population studies are available for Hornworts. Here we aim at filling some important gaps in Hornwort biology and biodiversity. We provide estimates of Hornwort species richness worldwide, identifying centers of diversity. We also present two examples of the impact of recent work in elucidating the composition and circumscription of the genera Megaceros and Nothoceros. Important areas for further research are highlighted, particularly at taxonomic, ultrastructural, phylogenetic and genomic levels.
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horizontal transfer of an adaptive chimeric photoreceptor from bryophytes to ferns
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Juan Carlos Villarreal, Steven L Kelly, Carl J Rothfels, Michael Melkonian, Eftychios Frangedakis, Markus Ruhsam, Erin M Sigel, Joshua P Der, Jarmila Pittermann, Dylan O BurgeAbstract:Ferns are well known for their shade-dwelling habits. Their ability to thrive under low-light conditions has been linked to the evolution of a novel chimeric photoreceptor—neochrome—that fuses red-sensing phytochrome and blue-sensing phototropin modules into a single gene, thereby optimizing phototropic responses. Despite being implicated in facilitating the diversification of modern ferns, the origin of neochrome has remained a mystery. We present evidence for neochrome in Hornworts (a bryophyte lineage) and demonstrate that ferns acquired neochrome from Hornworts via horizontal gene transfer (HGT). Fern neochromes are nested within Hornwort neochromes in our large-scale phylogenetic reconstructions of phototropin and phytochrome gene families. Divergence date estimates further support the HGT hypothesis, with fern and Hornwort neochromes diverging 179 Mya, long after the split between the two plant lineages (at least 400 Mya). By analyzing the draft genome of the Hornwort Anthoceros punctatus, we also discovered a previously unidentified phototropin gene that likely represents the ancestral lineage of the neochrome phototropin module. Thus, a neochrome originating in Hornworts was transferred horizontally to ferns, where it may have played a significant role in the diversification of modern ferns.
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Correlates of monoicy and dioicy in Hornworts, the apparent sister group to vascular plants
BMC Evolutionary Biology, 2013Co-Authors: Juan Carlos VillarrealAbstract:Background Whether male and female gametes are produced by single or separate individuals shapes plant mating and hence patterns of genetic diversity among and within populations. Haploid-dominant plants (“bryophytes”: liverworts, mosses and Hornworts) can have unisexual (dioicous) or bisexual (monoicous) gametophytes, and today, 68% of liverwort species, 57% of moss species, and 40% of Hornwort species are dioicous. The transitions between the two sexual systems and possible correlations with other traits have been studied in liverworts and mosses, but not Hornworts. Here we use a phylogeny for 98 of the 200 species of Hornworts, the sister group to vascular plants, representing roughly equal proportions of all monoicous and all dioicous species, to test whether transitions in sexual systems are predominantly from monoicy to dioicy as might be expected based on studies of mosses. We further investigate possible correlations between sexual system and spore size, antheridium number, ploidy level, and diversification rate, with character selection partly based on findings in mosses and liverworts. Results Hornworts underwent numerous transitions between monoicy and dioicy. The transition rate from dioicy to monoicy was 2× higher than in the opposite direction, but monoicous groups have higher extinction rates; diversification rates do not correlate with sexual system. A correlation important in mosses, that between monoicy and polyploidy, apparently plays a small role: of 20 species with chromosome counts, only one is polyploid, the monoicous Anthoceros punctatus . A contingency test revealed that transitions to dioicy were more likely in species with small spores, supporting the hypothesis that small but numerous spores may be advantageous for dioicous species that depend on dense carpets of gametophytes for reproductive assurance. However, we found no evidence for increased antheridium-per-chamber numbers in dioicous species. Conclusions Sexual systems in Hornworts are labile, and the higher number of extant monoicous species (60%) may be largely due to frequent transitions to monoicy.
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the plastid genome of the Hornwort nothoceros aenigmaticus dendrocerotaceae phylogenetic signal in inverted repeat expansion pseudogenization and intron gain
American Journal of Botany, 2013Co-Authors: Juan Carlos Villarreal, Laura L. Forrest, Norman J Wickett, Bernard GoffinetAbstract: Premise of the study: The previously sequenced plastome of the Hornwort Anthoceros angustus differs from that of other bryophytes by an expanded inverted repeat (IR) and the presence of a type I intron in the 23S ribosomal RNA ( rrn23 ) gene. We assembled the plastome of the Hornwort Nothoceros aenigmaticus , contrasted its architecture to that of other bryophytes, and assessed the phylogenetic signifi cance of genomic characters in Hornwort evolution. Methods: The Nothoceros plastome was reconstructed from shotgun sequencing of genomic DNA. Comparison with the Anthoceros plastome revealed three structural differences. We sequenced these regions in taxa spanning the Hornwort phylogeny. Key results: The Nothoceros plastome is colinear with other bryophyte plastomes, but differs from the Anthoceros plastome by several gene regions located within the IR in Anthoceros being in the large single-copy region in Nothoceros , by the rrn23 gene lacking an intron, and by the rpl2 being a pseudogene. Comparisons across the Hornwort phylogeny indicate that the fi rst two characters are restricted to Anthocerotaceae, while rpl2 pseudogenization diagnoses the sister lineage to Anthocerotaceae. Conclusions: The Nothoceros plastome is structurally similar to that of most bryophytes. However, we identifi ed more structural differences within Hornworts than have been described within either the mosses or the liverworts. The distribution of the gene duplication involving the IR and an intron in the rrn23 gene are restricted to Anthocerotaceae. Occurrence of the intron and the conserved intron sequence between Anthoceros and distantly related chlorophyte algae may be due to horizontal gene transfer.
Eftychios Frangedakis - One of the best experts on this subject based on the ideXlab platform.
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an agrobacterium mediated stable transformation technique for the Hornwort model anthoceros agrestis
New Phytologist, 2021Co-Authors: Eftychios Frangedakis, Manuel Waller, Tomoaki Nishiyama, Hirokazu Tsukaya, Yuling Yue, Michelle Tjahjadi, Andika Gunadi, Joyce Van Eck, Peter SzovenyiAbstract:Despite their key phylogenetic position and their unique biology, Hornworts have been widely overlooked. Until recently there was no Hornwort model species amenable to systematic experimental investigation. Anthoceros agrestis has been proposed as the model species to study Hornwort biology. We have developed an Agrobacterium-mediated method for the stable transformation of A. agrestis, a Hornwort model species for which a genetic manipulation technique was not yet available. High transformation efficiency was achieved by using thallus tissue grown under low light conditions. We generated a total of 274 transgenic A. agrestis lines expressing the β-glucuronidase (GUS), cyan, green, and yellow fluorescent proteins under control of the CaMV 35S promoter and several endogenous promoters. Nuclear and plasma membrane localization with multiple color fluorescent proteins was also confirmed. The transformation technique described here should pave the way for detailed molecular and genetic studies of Hornwort biology, providing much needed insight into the molecular mechanisms underlying symbiosis, carbon-concentrating mechanism, RNA editing and land plant evolution in general.
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a simple agrobacterium mediated stable transformation technique for the Hornwort model anthoceros agrestis
bioRxiv, 2021Co-Authors: Eftychios Frangedakis, Manuel Waller, Tomoaki Nishiyama, Hirokazu Tsukaya, Yuling Yue, Michelle Tjahjadi, Andika Gunadi, Joyce Van Eck, Peter SzovenyiAbstract:We have developed a simple Agrobacterium-mediated method for the stable transformation of the Hornwort Anthoceros agrestis, the fifth bryophyte species for which a genetic manipulation technique becomes available. High transformation efficiency was achieved by using thallus tissue grown under low-light conditions. We generated a total of 216 transgenic A. agrestis lines expressing the β-Glucuronidase (GUS), cyan, green, and yellow fluorescent proteins under the control of the CaMV 35S promoter and several endogenous promoters. Nuclear and plasma membrane localization with multiple color fluorescent proteins was also confirmed. The transformation technique described here should pave the way for detailed molecular and genetic studies of Hornwort biology, providing much needed insight into the molecular mechanisms underlying symbiosis, carbon-concentrating mechanism, RNA editing, and land plant evolution in general.
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Establishment of Anthoceros agrestis as a model species for studying the biology of Hornworts
BMC Plant Biology, 2015Co-Authors: Peter Szovenyi, Dietmar Quandt, Eftychios Frangedakis, Mariana Ricca, Susann Wicke, Jane A LangdaleAbstract:Background Plants colonized terrestrial environments approximately 480 million years ago and have contributed significantly to the diversification of life on Earth. Phylogenetic analyses position a subset of charophyte algae as the sister group to land plants, and distinguish two land plant groups that diverged around 450 million years ago – the bryophytes and the vascular plants. Relationships between liverworts, mosses Hornworts and vascular plants have proven difficult to resolve, and as such it is not clear which bryophyte lineage is the sister group to all other land plants and which is the sister to vascular plants. The lack of comparative molecular studies in representatives of all three lineages exacerbates this uncertainty. Such comparisons can be made between mosses and liverworts because representative model organisms are well established in these two bryophyte lineages. To date, however, a model Hornwort species has not been available. Results Here we report the establishment of Anthoceros agrestis as a model Hornwort species for laboratory experiments. Axenic culture conditions for maintenance and vegetative propagation have been determined, and treatments for the induction of sexual reproduction and sporophyte development have been established. In addition, protocols have been developed for the extraction of DNA and RNA that is of a quality suitable for molecular analyses. Analysis of haploid-derived genome sequence data of two A. agrestis isolates revealed single nucleotide polymorphisms at multiple loci, and thus these two strains are suitable starting material for classical genetic and mapping experiments. Conclusions Methods and resources have been developed to enable A. agrestis to be used as a model species for developmental, molecular, genomic, and genetic studies. This advance provides an unprecedented opportunity to investigate the biology of Hornworts.
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establishment of anthoceros agrestis as a model species for studying the biology of Hornworts
BMC Plant Biology, 2015Co-Authors: Peter Szovenyi, Dietmar Quandt, Eftychios Frangedakis, Mariana Ricca, Susann Wicke, Jane A LangdaleAbstract:Plants colonized terrestrial environments approximately 480 million years ago and have contributed significantly to the diversification of life on Earth. Phylogenetic analyses position a subset of charophyte algae as the sister group to land plants, and distinguish two land plant groups that diverged around 450 million years ago – the bryophytes and the vascular plants. Relationships between liverworts, mosses Hornworts and vascular plants have proven difficult to resolve, and as such it is not clear which bryophyte lineage is the sister group to all other land plants and which is the sister to vascular plants. The lack of comparative molecular studies in representatives of all three lineages exacerbates this uncertainty. Such comparisons can be made between mosses and liverworts because representative model organisms are well established in these two bryophyte lineages. To date, however, a model Hornwort species has not been available. Here we report the establishment of Anthoceros agrestis as a model Hornwort species for laboratory experiments. Axenic culture conditions for maintenance and vegetative propagation have been determined, and treatments for the induction of sexual reproduction and sporophyte development have been established. In addition, protocols have been developed for the extraction of DNA and RNA that is of a quality suitable for molecular analyses. Analysis of haploid-derived genome sequence data of two A. agrestis isolates revealed single nucleotide polymorphisms at multiple loci, and thus these two strains are suitable starting material for classical genetic and mapping experiments. Methods and resources have been developed to enable A. agrestis to be used as a model species for developmental, molecular, genomic, and genetic studies. This advance provides an unprecedented opportunity to investigate the biology of Hornworts.
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horizontal transfer of an adaptive chimeric photoreceptor from bryophytes to ferns
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Juan Carlos Villarreal, Steven L Kelly, Carl J Rothfels, Michael Melkonian, Eftychios Frangedakis, Markus Ruhsam, Erin M Sigel, Joshua P Der, Jarmila Pittermann, Dylan O BurgeAbstract:Ferns are well known for their shade-dwelling habits. Their ability to thrive under low-light conditions has been linked to the evolution of a novel chimeric photoreceptor—neochrome—that fuses red-sensing phytochrome and blue-sensing phototropin modules into a single gene, thereby optimizing phototropic responses. Despite being implicated in facilitating the diversification of modern ferns, the origin of neochrome has remained a mystery. We present evidence for neochrome in Hornworts (a bryophyte lineage) and demonstrate that ferns acquired neochrome from Hornworts via horizontal gene transfer (HGT). Fern neochromes are nested within Hornwort neochromes in our large-scale phylogenetic reconstructions of phototropin and phytochrome gene families. Divergence date estimates further support the HGT hypothesis, with fern and Hornwort neochromes diverging 179 Mya, long after the split between the two plant lineages (at least 400 Mya). By analyzing the draft genome of the Hornwort Anthoceros punctatus, we also discovered a previously unidentified phototropin gene that likely represents the ancestral lineage of the neochrome phototropin module. Thus, a neochrome originating in Hornworts was transferred horizontally to ferns, where it may have played a significant role in the diversification of modern ferns.
Griffiths Howard - One of the best experts on this subject based on the ideXlab platform.
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To concentrate or ventilate? Carbon acquisition, isotope discrimination and physiological ecology of early land plant life forms
Philosophical Transactions of the Royal Society B, 2008Co-Authors: Meyer Moritz, Seibt Ulli, Griffiths HowardAbstract:A comparative study has been made of the photosynthetic physiological ecology and carbon isotope discrimination characteristics for modern-day bryophytes and closely related algal groups. Firstly, the extent of bryophyte distribution and diversification as compared with more advanced land plant groups is considered. Secondly, measurements of instantaneous carbon isotope discrimination (D), photosynthetic CO2 assimilation and electron transport rates were compared during the drying cycles. The extent of surface diffusion limitation (when wetted), internal conductance and water use efficiency (WUE) at optimal tissue water content (TWC) were derived for liverworts and a Hornwort from contrasting habitats and with differing degrees of thallus ventilation (as intra-thalline cavities and internal airspaces). We also explore how the operation of a biophysical carbon-concentrating mechanism (CCM) tempers isotope discrimination characteristics in two other Hornworts, as well as the green algae Coleochaete orbicularis and Chlamydomonas reinhardtii. The magnitude of D was compared for each life form over a drying curve and used to derive the surface liquid-phase conductance (when wetted) and internal conductance (at optimal TWC). The magnitude of external and internal conductances, and WUE, was higher for ventilated, compared with non-ventilated, liverworts and Hornworts, but the values were similar within each group, suggesting that both factors have been optimized for each life form. For the Hornworts, leakiness of the CCM was highest for Megaceros vincentianus and C. orbicular is (approx. 30%) and, at 5%, lowest in C. reinhardtii grown under ambient CO2 concentrations. Finally, evidence for the operation of a CCM in algae and Hornworts is considered in terms of the probable role of the chloroplast pyrenoid, as the origins, structure and function of this enigmatic organelle are explored during the evolution of land plants.We thank D. C. Cargill and J. C. Villarreal for the Hornwort material. This research was supported by grant BFR06/30 from the Luxemburg Ministry of Culture, Higher Education and Research, and by the Ecology Section of the National Museum of Natural History, Luxemburg (Dr Christian Ries), as well as by the Department of Plant Sciences of the University of Cambridge
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To concentrate or ventilate? Carbon acquisition, isotope discrimination and physiological ecology of early land plant life forms.
Philos Trans R Soc Lond B Biol Sci, 2008Co-Authors: Meyer Moritz, Seibt Ulli, Griffiths HowardAbstract:A comparative study has been made of the photosynthetic physiological ecology and carbon isotope discrimination characteristics for modern-day bryophytes and closely related algal groups. Firstly, the extent of bryophyte distribution and diversification as compared with more advanced land plant groups is considered. Secondly, measurements of instantaneous carbon isotope discrimination (Delta), photosynthetic CO(2) assimilation and electron transport rates were compared during the drying cycles. The extent of surface diffusion limitation (when wetted), internal conductance and water use efficiency (WUE) at optimal tissue water content (TWC) were derived for liverworts and a Hornwort from contrasting habitats and with differing degrees of thallus ventilation (as intra-thalline cavities and internal airspaces). We also explore how the operation of a biophysical carbon-concentrating mechanism (CCM) tempers isotope discrimination characteristics in two other Hornworts, as well as the green algae Coleochaete orbicularis and Chlamydomonas reinhardtii. The magnitude of Delta was compared for each life form over a drying curve and used to derive the surface liquid-phase conductance (when wetted) and internal conductance (at optimal TWC). The magnitude of external and internal conductances, and WUE, was higher for ventilated, compared with non-ventilated, liverworts and Hornworts, but the values were similar within each group, suggesting that both factors have been optimized for each life form. For the Hornworts, leakiness of the CCM was highest for Megaceros vincentianus and C. orbicularis (approx. 30%) and, at 5%, lowest in C. reinhardtii grown under ambient CO2 concentrations. Finally, evidence for the operation of a CCM in algae and Hornworts is considered in terms of the probable role of the chloroplast pyrenoid, as the origins, structure and function of this enigmatic organelle are explored during the evolution of land plants.We thank D. C. Cargill and J. C. Villarreal for the Hornwort material. This research was supported by grant BFR06/30 from the Luxemburg Ministry of Culture, Higher Education and Research, and by the Ecology Section of the National Museum of Natural History, Luxemburg (Dr Christian Ries), as well as by the Department of Plant Sciences of the University of Cambridge
Mareike Schallenbergrudinger - One of the best experts on this subject based on the ideXlab platform.
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towards a plant model for enigmatic u to c rna editing the organelle genomes transcriptomes editomes and candidate rna editing factors in the Hornwort anthoceros agrestis
New Phytologist, 2020Co-Authors: Philipp Gerke, Henning Lenz, Peter Szovenyi, Anna Neubauer, Bernard Gutmann, Rose Mcdowell, Ian Small, Mareike SchallenbergrudingerAbstract:Hornworts are crucial to understand the phylogeny of early land plants. The emergence of ‘reverse’ U‐to‐C RNA editing accompanying the widespread C‐to‐U RNA editing in plant chloroplasts and mitochondria may be a molecular synapomorphy of a Hornwort–tracheophyte clade. C‐to‐U RNA editing is well understood after identification of many editing factors in models like Arabidopsis thaliana and Physcomitrella patens, but there is no plant model yet to investigate U‐to‐C RNA editing. The Hornwort Anthoceros agrestis is now emerging as such a model system. We report on the assembly and analyses of the A. agrestis chloroplast and mitochondrial genomes, their transcriptomes and editomes, and a large nuclear gene family encoding pentatricopeptide repeat (PPR) proteins likely acting as RNA editing factors. Both organelles in A. agrestis feature high amounts of RNA editing, with altogether > 1100 sites of C‐to‐U and 1300 sites of U‐to‐C editing. The nuclear genome reveals > 1400 genes for PPR proteins with variable carboxyterminal DYW domains. We observe significant variants of the ‘classic’ DYW domain, in the meantime confirmed as the cytidine deaminase for C‐to‐U editing, and discuss the first attractive candidates for reverse editing factors given their excellent matches to U‐to‐C editing targets according to the PPR‐RNA binding code.
