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Mok D, Leung A, Searles P, Sage TL, Sage RF. CAM photosynthesis in Bulnesia retama (Zygophyllaceae), a non-succulent desert shrub from South America. Ann Bot 2023; 132:655-670. [PMID: 37625031 PMCID: PMC10799978 DOI: 10.1093/aob/mcad114] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/19/2023] [Accepted: 08/23/2023] [Indexed: 08/27/2023]
Abstract
BACKGROUND AND AIMS Bulnesia retama is a drought-deciduous, xerophytic shrub from arid landscapes of South America. In a survey of carbon isotope ratios (δ13C) in specimens from the field, B. retama exhibited less negative values, indicative of CAM or C4 photosynthesis. Here, we investigate whether B. retama is a C4 or CAM plant. METHODS Gas-exchange responses to intercellular CO2, diurnal gas-exchange profiles, δ13C and dawn vs. afternoon titratable acidity were measured on leaves and stems of watered and droughted B. retama plants. Leaf and stem cross-sections were imaged to determine whether the tissues exhibited succulent CAM or C4 Kranz anatomy. KEY RESULTS Field-collected stems and fruits of B. retama exhibited δ13C between -16 and -19 ‰. Plants grown in a glasshouse from field-collected seeds had leaf δ13C values near -31 ‰ and stem δ13C values near -28 ‰. The CO2 response of photosynthesis showed that leaves and stems used C3 photosynthesis during the day, while curvature in the nocturnal response of net CO2 assimilation rate (A) in all stems, coupled with slightly positive rates of A at night, indicated modest CAM function. C4 photosynthesis was absent. Succulence was absent in all tissues, although stems exhibited tight packing of the cortical chlorenchyma in a CAM-like manner. Tissue titratable acidity increased at night in droughted stems. CONCLUSIONS Bulnesia retama is a weak to modest C3 + CAM plant. This is the first report of CAM in the Zygophyllaceae and the first showing that non-succulent, xerophytic shrubs use CAM. CAM alone in B. retama was too limited to explain less negative δ13C in field-collected plants, but combined with effects of low stomatal and mesophyll conductance it could raise δ13C to observed values between -16 and -19 ‰. Modest CAM activity, particularly during severe drought, could enable B. retama to persist in arid habitats of South America.
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Affiliation(s)
- Daniel Mok
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Wilcocks Street, Toronto, Ontario M5R3C6, Canada
| | - Arthur Leung
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Wilcocks Street, Toronto, Ontario M5R3C6, Canada
| | - Peter Searles
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR-CONICET), Entre Ríos y Mendoza s/n, Anillaco (5301), La Rioja, Argentina
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Wilcocks Street, Toronto, Ontario M5R3C6, Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Wilcocks Street, Toronto, Ontario M5R3C6, Canada
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Billakurthi K, Schulze S, Schulz ELM, Sage TL, Schreier TB, Hibberd JM, Ludwig M, Westhoff P. Shedding light on AT1G29480 of Arabidopsis thaliana-An enigmatic locus restricted to Brassicacean genomes. Plant Direct 2022; 6:e455. [PMID: 36263108 PMCID: PMC9576117 DOI: 10.1002/pld3.455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/02/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
A key feature of C4 Kranz anatomy is the presence of an enlarged, photosynthetically highly active bundle sheath whose cells contain large numbers of chloroplasts. With the aim to identify novel candidate regulators of C4 bundle sheath development, we performed an activation tagging screen with Arabidopsis thaliana. The reporter gene used encoded a chloroplast-targeted GFP protein preferentially expressed in the bundle sheath, and the promoter of the C4 phosphoenolpyruvate carboxylase gene from Flaveria trinervia served as activation tag because of its activity in all chlorenchymatous tissues of A. thaliana. Primary mutants were selected based on their GFP signal intensity, and one stable mutant named kb-1 with a significant increase in GFP fluorescence intensity was obtained. Despite the increased GFP signal, kb-1 showed no alterations to bundle sheath anatomy. The causal locus, AT1G29480, is specific to the Brassicaceae with its second exon being conserved. Overexpression and reconstitution studies confirmed that AT1G29480, and specifically its second exon, were sufficient for the enhanced GFP phenotype, which was not dependent on translation of the locus or its parts into protein. We conclude, therefore, that the AT1G29480 locus enhances the GFP reporter gene activity via an RNA-based mechanism.
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Affiliation(s)
- Kumari Billakurthi
- Institute of Plant Molecular and Developmental BiologyUniversitätsstrasse 1, Heinrich‐Heine‐UniversityDuesseldorfGermany
- Cluster of Excellence on Plant Sciences ‘From Complex Traits Towards Synthetic Modules’Düsseldorf‐CologneGermany
- Department of Plant Sciences, Downing StreetUniversity of CambridgeCambridgeUK
| | - Stefanie Schulze
- Institute of Plant Molecular and Developmental BiologyUniversitätsstrasse 1, Heinrich‐Heine‐UniversityDuesseldorfGermany
| | - Eva Lena Marie Schulz
- Institute of Plant Molecular and Developmental BiologyUniversitätsstrasse 1, Heinrich‐Heine‐UniversityDuesseldorfGermany
| | - Tammy L. Sage
- Department of Ecology and Evolutionary BiologyThe University of TorontoTorontoOntarioCanada
| | - Tina B. Schreier
- Department of Plant Sciences, Downing StreetUniversity of CambridgeCambridgeUK
| | - Julian M. Hibberd
- Department of Plant Sciences, Downing StreetUniversity of CambridgeCambridgeUK
| | - Martha Ludwig
- School of Molecular SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
| | - Peter Westhoff
- Institute of Plant Molecular and Developmental BiologyUniversitätsstrasse 1, Heinrich‐Heine‐UniversityDuesseldorfGermany
- Cluster of Excellence on Plant Sciences ‘From Complex Traits Towards Synthetic Modules’Düsseldorf‐CologneGermany
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Fan Y, Asao S, Furbank RT, von Caemmerer S, Day DA, Tcherkez G, Sage TL, Sage RF, Atkin OK. The crucial roles of mitochondria in supporting C 4 photosynthesis. New Phytol 2022; 233:1083-1096. [PMID: 34669188 DOI: 10.1111/nph.17818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
C4 photosynthesis involves a series of biochemical and anatomical traits that significantly improve plant productivity under conditions that reduce the efficiency of C3 photosynthesis. We explore how evolution of the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK types) has affected the functions and properties of mitochondria. Mitochondria in C4 NAD-ME and PCK types play a direct role in decarboxylation of metabolites for C4 photosynthesis. Mitochondria in C4 PCK type also provide ATP for C4 metabolism, although this role for ATP provision is not seen in NAD-ME type. Such involvement has increased mitochondrial abundance/size and associated enzymatic capacity, led to changes in mitochondrial location and ultrastructure, and altered the role of mitochondria in cellular carbon metabolism in the NAD-ME and PCK types. By contrast, these changes in mitochondrial properties are absent in the C4 NADP-ME type and C3 leaves, where mitochondria play no direct role in photosynthesis. From an eco-physiological perspective, rates of leaf respiration in darkness vary considerably among C4 species but does not differ systematically among the three C4 types. This review outlines further mitochondrial research in key areas central to the engineering of the C4 pathway into C3 plants and to the understanding of variation in rates of C4 dark respiration.
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Affiliation(s)
- Yuzhen Fan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Shinichi Asao
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Robert T Furbank
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Susanne von Caemmerer
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Guillaume Tcherkez
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Institut de Recherche en Horticulture et Semences, INRA and University of Angers, Beaucouzé, 49070, France
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
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Hüdig M, Tronconi MA, Zubimendi JP, Sage TL, Poschmann G, Bickel D, Gohlke H, Maurino VG. Respiratory and C4-photosynthetic NAD-malic enzyme coexist in bundle sheath cell mitochondria and evolved via association of differentially adapted subunits. Plant Cell 2022; 34:597-615. [PMID: 34734993 PMCID: PMC8773993 DOI: 10.1093/plcell/koab265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/26/2021] [Indexed: 05/29/2023]
Abstract
In plant mitochondria, nicotinamide adenine dinucleotide-malic enzyme (NAD-ME) has a housekeeping function in malate respiration. In different plant lineages, NAD-ME was independently co-opted in C4 photosynthesis. In the C4 Cleome species, Gynandropsis gynandra and Cleome angustifolia, all NAD-ME genes (NAD-MEα, NAD-MEβ1, and NAD-MEβ2) were affected by C4 evolution and are expressed at higher levels than their orthologs in the C3 species Tarenaya hassleriana. In T. hassleriana, the NAD-ME housekeeping function is performed by two heteromers, NAD-MEα/β1 and NAD-MEα/β2, with similar biochemical properties. In both C4 species, this role is restricted to NAD-MEα/β2. In the C4 species, NAD-MEα/β1 is exclusively present in the leaves, where it accounts for most of the enzymatic activity. Gynandropsis gynandra NAD-MEα/β1 (GgNAD-MEα/β1) exhibits high catalytic efficiency and is differentially activated by the C4 intermediate aspartate, confirming its role as the C4-decarboxylase. During C4 evolution, NAD-MEβ1 lost its catalytic activity; its contribution to the enzymatic activity results from a stabilizing effect on the associated α-subunit and the acquisition of regulatory properties. We conclude that in bundle sheath cell mitochondria of C4 species, the functions of NAD-ME as C4 photosynthetic decarboxylase and as a housekeeping enzyme coexist and are performed by isoforms that combine the same α-subunit with differentially adapted β-subunits.
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Affiliation(s)
- Meike Hüdig
- Molekulare Pflanzenphysiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Kirschallee, Bonn 53115, Germany
| | - Marcos A Tronconi
- Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
| | - Juan P Zubimendi
- Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
| | - Tammy L Sage
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Gereon Poschmann
- Molecular Proteomics Laboratory, Biomedical Research Centre (BMFZ) & Institute of Molecular Medicine, Proteome Research, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany
| | - David Bickel
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry) & Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, Jülich 52425, Germany
| | - Veronica G Maurino
- Molekulare Pflanzenphysiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Kirschallee, Bonn 53115, Germany
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Lee D, Hua L, Khoshravesh R, Giuliani R, Kumar I, Cousins A, Sage TL, Hibberd JM, Brutnell TP. Engineering chloroplast development in rice through cell-specific control of endogenous genetic circuits. Plant Biotechnol J 2021; 19:2291-2303. [PMID: 34328250 PMCID: PMC8541780 DOI: 10.1111/pbi.13660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/21/2021] [Accepted: 06/25/2021] [Indexed: 05/03/2023]
Abstract
The engineering of C4 photosynthetic activity into the C3 plant rice has the potential to nearly double rice yields. To engineer a two-cell photosynthetic system in rice, the rice bundle sheath (BS) must be rewired to enhance photosynthetic capacity. Here, we show that BS chloroplast biogenesis is enhanced when the transcriptional activator, Oryza sativa Cytokinin GATA transcription factor 1 (OsCGA1), is driven by a vascular specific promoter. Ectopic expression of OsCGA1 resulted in increased BS chloroplast planar area and increased expression of photosynthesis-associated nuclear genes (PhANG), required for the biogenesis of photosynthetically active chloroplasts in BS cells of rice. A further refinement using a DNAse dead Cas9 (dCas9) activation module driven by the same cell-type specific promoter, directed enhanced chloroplast development of the BS cells when gRNA sequences were delivered by the dCas9 module to the promoter of the endogenous OsCGA1 gene. Single gRNA expression was sufficient to mediate the transactivation of both the endogenous gene and a transgenic GUS reporter fused with OsCGA1 promoter. Our results illustrate the potential for tissue-specific dCas9-activation and the co-regulation of genes needed for multistep engineering of C4 rice.
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Affiliation(s)
| | - Lei Hua
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biologythe University of TorontoTorontoONCanada
- Department of Biologythe University of New MexicoAlbuquerqueNMUSA
| | - Rita Giuliani
- School of Biological SciencesWashington State UniversityPullmanWAUSA
| | | | - Asaph Cousins
- School of Biological SciencesWashington State UniversityPullmanWAUSA
| | - Tammy L. Sage
- Department of Ecology and Evolutionary Biologythe University of TorontoTorontoONCanada
| | | | - Thomas P. Brutnell
- Donald Danforth Plant Science CenterSt. LouisMOUSA
- Biotechnology Research InstituteChinese Academy of Agricultural SciencesBeijingChina
- Joint Laboratory for Photosynthesis Enhancement and C4 Rice DevelopmentBiotechnology Research InstituteChinese Academy of Agricultural SciencesBeijingChina
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6
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Zamani-Nour S, Lin HC, Walker BJ, Mettler-Altmann T, Khoshravesh R, Karki S, Bagunu E, Sage TL, Quick WP, Weber APM. Overexpression of the chloroplastic 2-oxoglutarate/malate transporter disturbs carbon and nitrogen homeostasis in rice. J Exp Bot 2021; 72:137-152. [PMID: 32710115 PMCID: PMC7816853 DOI: 10.1093/jxb/eraa343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/07/2020] [Accepted: 07/21/2020] [Indexed: 05/07/2023]
Abstract
The chloroplastic 2-oxaloacetate (OAA)/malate transporter (OMT1 or DiT1) takes part in the malate valve that protects chloroplasts from excessive redox poise through export of malate and import of OAA. Together with the glutamate/malate transporter (DCT1 or DiT2), it connects carbon with nitrogen assimilation, by providing 2-oxoglutarate for the GS/GOGAT (glutamine synthetase/glutamate synthase) reaction and exporting glutamate to the cytoplasm. OMT1 further plays a prominent role in C4 photosynthesis: OAA resulting from phosphoenolpyruvate carboxylation is imported into the chloroplast, reduced to malate by plastidic NADP-malate dehydrogenase, and then exported for transport to bundle sheath cells. Both transport steps are catalyzed by OMT1, at the rate of net carbon assimilation. To engineer C4 photosynthesis into C3 crops, OMT1 must be expressed in high amounts on top of core C4 metabolic enzymes. We report here high-level expression of ZmOMT1 from maize in rice (Oryza sativa ssp. indica IR64). Increased activity of the transporter in transgenic rice was confirmed by reconstitution of transporter activity into proteoliposomes. Unexpectedly, overexpression of ZmOMT1 in rice negatively affected growth, CO2 assimilation rate, total free amino acid content, tricarboxylic acid cycle metabolites, as well as sucrose and starch contents. Accumulation of high amounts of aspartate and the impaired growth phenotype of OMT1 rice lines could be suppressed by simultaneous overexpression of ZmDiT2. Implications for engineering C4 rice are discussed.
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Affiliation(s)
- Shirin Zamani-Nour
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine University, Düsseldorf, Germany
| | - Hsiang-Chun Lin
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Berkley J Walker
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine University, Düsseldorf, Germany
| | - Tabea Mettler-Altmann
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine University, Düsseldorf, Germany
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Shanta Karki
- National Center for Fruit Development, Kirtipur, Kathmandu, Nepal
| | - Efren Bagunu
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - W Paul Quick
- International Rice Research Institute, Los Baños, Laguna, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine University, Düsseldorf, Germany
- Correspondence:
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7
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Khoshravesh R, Stata M, Adachi S, Sage TL, Sage RF. Evolutionary Convergence of C 4 Photosynthesis: A Case Study in the Nyctaginaceae. Front Plant Sci 2020; 11:578739. [PMID: 33224166 PMCID: PMC7667235 DOI: 10.3389/fpls.2020.578739] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/06/2020] [Indexed: 05/27/2023]
Abstract
C4 photosynthesis evolved over 65 times, with around 24 origins in the eudicot order Caryophyllales. In the Caryophyllales family Nyctaginaceae, the C4 pathway is known in three genera of the tribe Nyctagineae: Allionia, Okenia and Boerhavia. Phylogenetically, Allionia and Boerhavia/Okenia are separated by three genera whose photosynthetic pathway is uncertain. To clarify the distribution of photosynthetic pathways in the Nyctaginaceae, we surveyed carbon isotope ratios of 159 species of the Nyctaginaceae, along with bundle sheath (BS) cell ultrastructure, leaf gas exchange, and C4 pathway biochemistry in five species from the two C4 clades and closely related C3 genera. All species in Allionia, Okenia and Boerhavia are C4, while no C4 species occur in any other genera of the family, including three that branch between Allionia and Boerhavia. This demonstrates that C4 photosynthesis evolved twice in Nyctaginaceae. Boerhavia species use the NADP-malic enzyme (NADP-ME) subtype of C4 photosynthesis, while Allionia species use the NAD-malic enzyme (NAD-ME) subtype. The BS cells of Allionia have many more mitochondria than the BS of Boerhavia. Bundle sheath mitochondria are closely associated with chloroplasts in Allionia which facilitates CO2 refixation following decarboxylation by mitochondrial NAD-ME. The close relationship between Allionia and Boerhavia could provide insights into why NADP-ME versus NAD-ME subtypes evolve, particularly when coupled to analysis of their respective genomes. As such, the group is an excellent system to dissect the organizational hierarchy of convergent versus divergent traits produced by C4 evolution, enabling us to understand when convergence is favored versus when divergent modifications can result in a common phenotype.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
- Department of Biology, The University of New Mexico, Albuquerque, NM, United States
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
| | - Shunsuke Adachi
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tammy L. Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
| | - Rowan F. Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
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Khoshravesh R, Stata M, Busch FA, Saladié M, Castelli JM, Dakin N, Hattersley PW, Macfarlane TD, Sage RF, Ludwig M, Sage TL. The Evolutionary Origin of C 4 Photosynthesis in the Grass Subtribe Neurachninae. Plant Physiol 2020; 182:566-583. [PMID: 31611421 PMCID: PMC6945869 DOI: 10.1104/pp.19.00925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 05/10/2023]
Abstract
The Australian grass subtribe Neurachninae contains closely related species that use C3, C4, and C2 photosynthesis. To gain insight into the evolution of C4 photosynthesis in grasses, we examined leaf gas exchange, anatomy and ultrastructure, and tissue localization of Gly decarboxylase subunit P (GLDP) in nine Neurachninae species. We identified previously unrecognized variation in leaf structure and physiology within Neurachne that represents varying degrees of C3-C4 intermediacy in the Neurachninae. These include inverse correlations between the apparent photosynthetic carbon dioxide (CO2) compensation point in the absence of day respiration (C * ) and chloroplast and mitochondrial investment in the mestome sheath (MS), where CO2 is concentrated in C2 and C4 Neurachne species; width of the MS cells; frequency of plasmodesmata in the MS cell walls adjoining the parenchymatous bundle sheath; and the proportion of leaf GLDP invested in the MS tissue. Less than 12% of the leaf GLDP was allocated to the MS of completely C3 Neurachninae species with C * values of 56-61 μmol mol-1, whereas two-thirds of leaf GLDP was in the MS of Neurachne lanigera, which exhibits a newly-identified, partial C2 phenotype with C * of 44 μmol mol-1 Increased investment of GLDP in MS tissue of the C2 species was attributed to more MS mitochondria and less GLDP in mesophyll mitochondria. These results are consistent with a model where C4 evolution in Neurachninae initially occurred via an increase in organelle and GLDP content in MS cells, which generated a sink for photorespired CO2 in MS tissues.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Florian A Busch
- Research School of Biology and Australian Research Council Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Montserrat Saladié
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Joanne M Castelli
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Nicole Dakin
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Paul W Hattersley
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Terry D Macfarlane
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
- Western Australian Herbarium, Department of Biodiversity, Conservation and Attractions, Perth, Western Australia 6983 Australia
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Martha Ludwig
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
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9
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Stata M, Sage TL, Sage RF. Mind the gap: the evolutionary engagement of the C 4 metabolic cycle in support of net carbon assimilation. Curr Opin Plant Biol 2019; 49:27-34. [PMID: 31150949 DOI: 10.1016/j.pbi.2019.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/20/2019] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
C4 photosynthesis evolved dozens of times, with a critical step being the engagement of a C4 metabolic cycle to concentrate CO2 into a bundle sheath-like compartment. While C3-C4 intermediate species show a progressive increase in the activity of a C4 metabolic cycle, the integration of the C4 and C3 biochemical cycles in enhancing photosynthetic carbon gain occurs in a punctuated manner, at an initial C4 cycle activity near 60%. Punctuated integration of the C4 cycle could result from the evolutionary acquisition of traits that coordinate the C3 and C4 biochemical cycles (for example, an enzymatic, regulatory or transport function) or from a sudden reduction in the mesophyll C3 cycle. Alternatively, a punctuated pattern could be an artifact of low numbers of C3-C4 intermediates in the evolutionary space where C4 cycle engagement occurs, due to incomplete sampling of natural diversity or evolutionary dynamics rendering such intermediates unstable. Understanding how the C4 cycle becomes integrated with the C3 cycle could reveal new avenues for engineering the C4 pathway into C3 plants. Such efforts would be facilitated by the generation of hybrids, or the discovery of additional intermediates, that span the transition from low to high C4 cycle engagement.
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Affiliation(s)
- Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, M5S3B2, Canada
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, M5S3B2, Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, M5S3B2, Canada.
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10
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Döring F, Billakurthi K, Gowik U, Sultmanis S, Khoshravesh R, Das Gupta S, Sage TL, Westhoff P. Reporter-based forward genetic screen to identify bundle sheath anatomy mutants in A. thaliana. Plant J 2019; 97:984-995. [PMID: 30447112 PMCID: PMC6850095 DOI: 10.1111/tpj.14165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/31/2018] [Accepted: 11/06/2018] [Indexed: 05/22/2023]
Abstract
The evolution of C4 photosynthesis proceeded stepwise with each small step increasing the fitness of the plant. An important pre-condition for the introduction of a functional C4 cycle is the photosynthetic activation of the C3 bundle sheath by increasing its volume and organelle number. Therefore, to engineer C4 photosynthesis into existing C3 crops, information about genes that control the bundle sheath cell size and organelle content is needed. However, very little information is known about the genes that could be manipulated to create a more C4 -like bundle sheath. To this end, an ethylmethanesulfonate (EMS)-based forward genetic screen was established in the Brassicaceae C3 species Arabidopsis thaliana. To ensure a high-throughput primary screen, the bundle sheath cells of A. thaliana were labeled using a luciferase (LUC68) or by a chloroplast-targeted green fluorescent protein (sGFP) reporter using a bundle sheath specific promoter. The signal strengths of the reporter genes were used as a proxy to search for mutants with altered bundle sheath anatomy. Here, we show that our genetic screen predominantly identified mutants that were primarily affected in the architecture of the vascular bundle, and led to an increase in bundle sheath volume. By using a mapping-by-sequencing approach the genomic segments that contained mutated candidate genes were identified.
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Affiliation(s)
- Florian Döring
- Institute of Plant Molecular and Developmental BiologyHeinrich‐Heine UniversityUniversitätsstrasse 140225DuesseldorfGermany
| | - Kumari Billakurthi
- Institute of Plant Molecular and Developmental BiologyHeinrich‐Heine UniversityUniversitätsstrasse 140225DuesseldorfGermany
- Cluster of Excellence on Plant Sciences ‘From Complex Traits towards Synthetic Modules’40225 Duesseldorf and50923CologneGermany
| | - Udo Gowik
- Institute of Plant Molecular and Developmental BiologyHeinrich‐Heine UniversityUniversitätsstrasse 140225DuesseldorfGermany
- Department of Biology and Environmental SciencesCarl Von Ossietzky UniversityAmmerlaender Heerstrasse 11426129OldenburgGermany
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary BiologyThe University of TorontoTorontoONM5S 3B2Canada
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary BiologyThe University of TorontoTorontoONM5S 3B2Canada
| | - Shipan Das Gupta
- Institute of Plant Molecular and Developmental BiologyHeinrich‐Heine UniversityUniversitätsstrasse 140225DuesseldorfGermany
| | - Tammy L. Sage
- Department of Ecology and Evolutionary BiologyThe University of TorontoTorontoONM5S 3B2Canada
| | - Peter Westhoff
- Institute of Plant Molecular and Developmental BiologyHeinrich‐Heine UniversityUniversitätsstrasse 140225DuesseldorfGermany
- Cluster of Excellence on Plant Sciences ‘From Complex Traits towards Synthetic Modules’40225 Duesseldorf and50923CologneGermany
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11
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Lundgren MR, Dunning LT, Olofsson JK, Moreno-Villena JJ, Bouvier JW, Sage TL, Khoshravesh R, Sultmanis S, Stata M, Ripley BS, Vorontsova MS, Besnard G, Adams C, Cuff N, Mapaura A, Bianconi ME, Long CM, Christin PA, Osborne CP. C 4 anatomy can evolve via a single developmental change. Ecol Lett 2018; 22:302-312. [PMID: 30557904 PMCID: PMC6849723 DOI: 10.1111/ele.13191] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 01/05/2023]
Abstract
C4 photosynthesis is a complex trait that boosts productivity in warm environments. Paradoxically, it evolved independently in numerous plant lineages, despite requiring specialised leaf anatomy. The anatomical modifications underlying C4 evolution have previously been evaluated through interspecific comparisons, which capture numerous changes besides those needed for C4 functionality. Here, we quantify the anatomical changes accompanying the transition between non‐C4 and C4 phenotypes by sampling widely across the continuum of leaf anatomical traits in the grass Alloteropsis semialata. Within this species, the only trait that is shared among and specific to C4 individuals is an increase in vein density, driven specifically by minor vein development that yields multiple secondary effects facilitating C4 function. For species with the necessary anatomical preconditions, developmental proliferation of veins can therefore be sufficient to produce a functional C4 leaf anatomy, creating an evolutionary entry point to complex C4 syndromes that can become more specialised.
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Affiliation(s)
- Marjorie R Lundgren
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Luke T Dunning
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Jill K Olofsson
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Jose J Moreno-Villena
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Jacques W Bouvier
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Brad S Ripley
- Botany Department, Rhodes University, Grahamstown, 6139, South Africa
| | - Maria S Vorontsova
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK
| | - Guillaume Besnard
- Laboratoire Évolution & Diversité Biologique (EDB UMR5174), Université de Toulouse, CNRS, ENSFEA, UPS, IRD, 118 route de Narbonne, 31062, Toulouse, France
| | - Claire Adams
- Botany Department, Rhodes University, Grahamstown, 6139, South Africa
| | - Nicholas Cuff
- Northern Territory Herbarium, Department of Environment and Natural Resources, PO Box 496, Palmerston, NT, 0831, Australia
| | | | - Matheus E Bianconi
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Christine M Long
- Department of Primary Industry and Fisheries, Northern Territory Government, Darwin, NT, 0801, Australia
| | - Pascal-Antoine Christin
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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12
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Wang P, Khoshravesh R, Karki S, Tapia R, Balahadia CP, Bandyopadhyay A, Quick WP, Furbank R, Sage TL, Langdale JA. Re-creation of a Key Step in the Evolutionary Switch from C 3 to C 4 Leaf Anatomy. Curr Biol 2017; 27:3278-3287.e6. [PMID: 29056456 PMCID: PMC5678070 DOI: 10.1016/j.cub.2017.09.040] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 12/26/2022]
Abstract
The C4 photosynthetic pathway accounts for ∼25% of primary productivity on the planet despite being used by only 3% of species. Because C4 plants are higher yielding than C3 plants, efforts are underway to introduce the C4 pathway into the C3 crop rice. This is an ambitious endeavor; however, the C4 pathway evolved from C3 on multiple independent occasions over the last 30 million years, and steps along the trajectory are evident in extant species. One approach toward engineering C4 rice is to recapitulate this trajectory, one of the first steps of which was a change in leaf anatomy. The transition from C3 to so-called "proto-Kranz" anatomy requires an increase in organelle volume in sheath cells surrounding leaf veins. Here we induced chloroplast and mitochondrial development in rice vascular sheath cells through constitutive expression of maize GOLDEN2-LIKE genes. Increased organelle volume was accompanied by the accumulation of photosynthetic enzymes and by increased intercellular connections. This suite of traits reflects that seen in "proto-Kranz" species, and, as such, a key step toward engineering C4 rice has been achieved.
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Affiliation(s)
- Peng Wang
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S3B2, Canada
| | - Shanta Karki
- International Rice Research Institute (IRRI), Los Banos 4030, Laguna, the Philippines
| | - Ronald Tapia
- International Rice Research Institute (IRRI), Los Banos 4030, Laguna, the Philippines
| | - C Paolo Balahadia
- International Rice Research Institute (IRRI), Los Banos 4030, Laguna, the Philippines
| | - Anindya Bandyopadhyay
- International Rice Research Institute (IRRI), Los Banos 4030, Laguna, the Philippines
| | - W Paul Quick
- International Rice Research Institute (IRRI), Los Banos 4030, Laguna, the Philippines; Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Robert Furbank
- CSIRO, Canberra, ACT 2601, Australia; ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT 2601, Australia
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S3B2, Canada.
| | - Jane A Langdale
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
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13
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Khoshravesh R, Lundsgaard-Nielsen V, Sultmanis S, Sage TL. Light Microscopy, Transmission Electron Microscopy, and Immunohistochemistry Protocols for Studying Photorespiration. Methods Mol Biol 2017; 1653:243-270. [PMID: 28822138 DOI: 10.1007/978-1-4939-7225-8_17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
High-resolution images obtained from plant tissues processed for light microscopy, transmission electron microscopy, and immunohistochemistry have provided crucial links between plant subcellular structure and physiology during photorespiration as well as the impact of photorespiration on plant evolution and development. This chapter presents established protocols to guide researchers in the preparation of plant tissues for high-resolution imaging with a light and transmission electron microscope and detection of proteins using immunohistochemistry. Discussion of concepts and theory behind each step in the process from tissue preservation to staining of resin-embedded tissues is included to enhance the understanding of all steps in the procedure. We also include a brief protocol for quantification of cellular parameters from high-resolution images to help researchers rigorously test hypotheses.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON, Canada, M5S 3B2
| | - Vanessa Lundsgaard-Nielsen
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON, Canada, M5S 3B2
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON, Canada, M5S 3B2
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON, Canada, M5S 3B2.
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14
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Yerramsetty P, Stata M, Siford R, Sage TL, Sage RF, Wong GKS, Albert VA, Berry JO. Evolution of RLSB, a nuclear-encoded S1 domain RNA binding protein associated with post-transcriptional regulation of plastid-encoded rbcL mRNA in vascular plants. BMC Evol Biol 2016; 16:141. [PMID: 27356975 PMCID: PMC4928308 DOI: 10.1186/s12862-016-0713-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/14/2016] [Indexed: 11/16/2022] Open
Abstract
Background RLSB, an S-1 domain RNA binding protein of Arabidopsis, selectively binds rbcL mRNA and co-localizes with Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) within chloroplasts of C3 and C4 plants. Previous studies using both Arabidopsis (C3) and maize (C4) suggest RLSB homologs are post-transcriptional regulators of plastid-encoded rbcL mRNA. While RLSB accumulates in all Arabidopsis leaf chlorenchyma cells, in C4 leaves RLSB-like proteins accumulate only within Rubisco-containing bundle sheath chloroplasts of Kranz-type species, and only within central compartment chloroplasts in the single cell C4 plant Bienertia. Our recent evidence implicates this mRNA binding protein as a primary determinant of rbcL expression, cellular localization/compartmentalization, and photosynthetic function in all multicellular green plants. This study addresses the hypothesis that RLSB is a highly conserved Rubisco regulatory factor that occurs in the chloroplasts all higher plants. Results Phylogenetic analysis has identified RLSB orthologs and paralogs in all major plant groups, from ancient liverworts to recent angiosperms. RLSB homologs were also identified in algae of the division Charophyta, a lineage closely related to land plants. RLSB-like sequences were not identified in any other algae, suggesting that it may be specific to the evolutionary line leading to land plants. The RLSB family occurs in single copy across most angiosperms, although a few species with two copies were identified, seemingly randomly distributed throughout the various taxa, although perhaps correlating in some cases with known ancient whole genome duplications. Monocots of the order Poales (Poaceae and Cyperaceae) were found to contain two copies, designated here as RLSB-a and RLSB-b, with only RLSB-a implicated in the regulation of rbcL across the maize developmental gradient. Analysis of microsynteny in angiosperms revealed high levels of conservation across eudicot species and for both paralogs in grasses, highlighting the possible importance of maintaining this gene and its surrounding genomic regions. Conclusions Findings presented here indicate that the RLSB family originated as a unique gene in land plant evolution, perhaps in the common ancestor of charophytes and higher plants. Purifying selection has maintained this as a highly conserved single- or two-copy gene across most extant species, with several conserved gene duplications. Together with previous findings, this study suggests that RLSB has been sustained as an important regulatory protein throughout the course of land plant evolution. While only RLSB-a has been directly implicated in rbcL regulation in maize, RLSB-b could have an overlapping function in the co-regulation of rbcL, or may have diverged as a regulator of one or more other plastid-encoded mRNAs. This analysis confirms that RLSB is an important and unique photosynthetic regulatory protein that has been continuously expressed in land plants as they emerged and diversified from their ancient common ancestor. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0713-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pradeep Yerramsetty
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S3B2, Canada
| | - Rebecca Siford
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S3B2, Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S3B2, Canada
| | - Gane Ka-Shu Wong
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.,Department of Medicine, University of Alberta, Edmonton, AB, T6G 2E1, Canada.,BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen, 518083, China
| | - Victor A Albert
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA.
| | - James O Berry
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA.
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15
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Lin H, Karki S, Coe RA, Bagha S, Khoshravesh R, Balahadia CP, Ver Sagun J, Tapia R, Israel WK, Montecillo F, de Luna A, Danila FR, Lazaro A, Realubit CM, Acoba MG, Sage TL, von Caemmerer S, Furbank RT, Cousins AB, Hibberd JM, Quick WP, Covshoff S. Targeted Knockdown of GDCH in Rice Leads to a Photorespiratory-Deficient Phenotype Useful as a Building Block for C4 Rice. Plant Cell Physiol 2016; 57:919-32. [PMID: 26903527 DOI: 10.1093/pcp/pcw033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 02/10/2016] [Indexed: 05/07/2023]
Abstract
The glycine decarboxylase complex (GDC) plays a critical role in the photorespiratory C2 cycle of C3 species by recovering carbon following the oxygenation reaction of ribulose-1,5-bisphosphate carboxylase/oxygenase. Loss of GDC from mesophyll cells (MCs) is considered a key early step in the evolution of C4 photosynthesis. To assess the impact of preferentially reducing GDC in rice MCs, we decreased the abundance of OsGDCH (Os10g37180) using an artificial microRNA (amiRNA) driven by a promoter that preferentially drives expression in MCs. GDC H- and P-proteins were undetectable in leaves of gdch lines. Plants exhibited a photorespiratory-deficient phenotype with stunted growth, accelerated leaf senescence, reduced chlorophyll, soluble protein and sugars, and increased glycine accumulation in leaves. Gas exchange measurements indicated an impaired ability to regenerate ribulose 1,5-bisphosphate in photorespiratory conditions. In addition, MCs of gdch lines exhibited a significant reduction in chloroplast area and coverage of the cell wall when grown in air, traits that occur during the later stages of C4 evolution. The presence of these two traits important for C4 photosynthesis and the non-lethal, down-regulation of the photorespiratory C2 cycle positively contribute to efforts to produce a C4 rice prototype.
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Affiliation(s)
- HsiangChun Lin
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines These authors contributed equally to this work
| | - Shanta Karki
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines These authors contributed equally to this work
| | - Robert A Coe
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines These authors contributed equally to this work
| | - Shaheen Bagha
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Canada
| | - Roxana Khoshravesh
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Canada
| | - C Paolo Balahadia
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Julius Ver Sagun
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Ronald Tapia
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - W Krystler Israel
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | | | - Albert de Luna
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Florence R Danila
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Andrea Lazaro
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Czarina M Realubit
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Michelle G Acoba
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines
| | - Tammy L Sage
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Canada
| | - Susanne von Caemmerer
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Acton, 2601, Australia
| | - Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Acton, 2601, Australia
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - W Paul Quick
- C4 Rice Center, International Rice Research Institute, Los Baños, Philippines Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
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16
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Khoshravesh R, Stinson CR, Stata M, Busch FA, Sage RF, Ludwig M, Sage TL. C3-C4 intermediacy in grasses: organelle enrichment and distribution, glycine decarboxylase expression, and the rise of C2 photosynthesis. J Exp Bot 2016; 67:3065-78. [PMID: 27073202 PMCID: PMC4867898 DOI: 10.1093/jxb/erw150] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Photorespiratory glycine shuttling and decarboxylation in bundle sheath (BS) cells exhibited by C2 species is proposed to be the evolutionary bridge to C4 photosynthesis in eudicots. To evaluate this in grasses, we compare anatomy, cellular localization of glycine decarboxylase (GDC), and photosynthetic physiology of a suspected C2 grass, Homolepis aturensis, with these traits in known C2 grasses, Neurachne minor and Steinchisma hians, and C3 S laxum that is sister to S hians We also use publicly available genome and RNA-sequencing data to examine the evolution of GDC subunits and enhance our understanding of the evolution of BS-specific GDC expression in C2 and C4 grasses. Our results confirm the identity of H aturensis as a C2 species; GDC is confined predominantly to the organelle-enriched BS cells in H aturensis and S hians and to mestome sheath cells of N minor Phylogenetic analyses and data obtained from immunodetection of the P-subunit of GDC are consistent with the hypothesis that the BS dominant levels of GDC in C2 and C4 species are due to changes in expression of a single GLDP gene in M and BS cells. All BS mitochondria and peroxisomes and most chloroplasts in H aturensis and S hians are situated centripetally in a pattern identical to C2 eudicots. In S laxum, which has C3-like gas exchange patterns, mitochondria and peroxisomes are positioned centripetally as they are in S hians This subcellular phenotype, also present in eudicots, is posited to initiate a facilitation cascade leading to C2 and C4 photosynthesis.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Ontario, ON M5S 3B2, Canada
| | - Corey R Stinson
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Ontario, ON M5S 3B2, Canada
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Ontario, ON M5S 3B2, Canada
| | - Florian A Busch
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Ontario, ON M5S 3B2, Canada
| | - Martha Ludwig
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, WA 6009, Australia
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Ontario, ON M5S 3B2, Canada
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17
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Stata M, Sage TL, Hoffmann N, Covshoff S, Ka-Shu Wong G, Sage RF. Mesophyll Chloroplast Investment in C3, C4 and C2 Species of the Genus Flaveria. Plant Cell Physiol 2016; 57:904-918. [PMID: 26985020 DOI: 10.1093/pcp/pcw015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/07/2016] [Indexed: 06/05/2023]
Abstract
The mesophyll (M) cells of C4 plants contain fewer chloroplasts than observed in related C3 plants; however, it is uncertain where along the evolutionary transition from C3 to C4 that the reduction in M chloroplast number occurs. Using 18 species in the genus Flaveria, which contains C3, C4 and a range of C3-C4 intermediate species, we examined changes in chloroplast number and size per M cell, and positioning of chloroplasts relative to the M cell periphery. Chloroplast number and coverage of the M cell periphery declined in proportion to increasing strength of C4 metabolism in Flaveria, while chloroplast size increased with increasing C4 cycle strength. These changes increase cytosolic exposure to the cell periphery which could enhance diffusion of inorganic carbon to phosphenolpyruvate carboxylase (PEPC), a cytosolic enzyme. Analysis of the transcriptome from juvenile leaves of nine Flaveria species showed that the transcript abundance of four genes involved in plastid biogenesis-FtsZ1, FtsZ2, DRP5B and PARC6-was negatively correlated with variation in C4 cycle strength and positively correlated with M chloroplast number per planar cell area. Chloroplast size was negatively correlated with abundance of FtsZ1, FtsZ2 and PARC6 transcripts. These results indicate that natural selection targeted the proteins of the contractile ring assembly to effect the reduction in chloroplast numbers in the M cells of C4 Flaveria species. If so, efforts to engineer the C4 pathway into C3 plants might evaluate whether inducing transcriptome changes similar to those observed in Flaveria could reduce M chloroplast numbers, and thus introduce a trait that appears essential for efficient C4 function.
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Affiliation(s)
- Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Natalie Hoffmann
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Gane Ka-Shu Wong
- Department of Biological Sciences, University of Alberta, Edmonton AB, T6G 2E9, Canada Department of Medicine, University of Alberta, Edmonton AB, T6G 2E1, Canada BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, China
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
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18
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Covshoff S, Szecowka M, Hughes TE, Smith-Unna R, Kelly S, Bailey KJ, Sage TL, Pachebat JA, Leegood R, Hibberd JM. C4 Photosynthesis in the Rice Paddy: Insights from the Noxious Weed Echinochloa glabrescens. Plant Physiol 2016; 170:57-73. [PMID: 26527656 PMCID: PMC4704570 DOI: 10.1104/pp.15.00889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 10/22/2015] [Accepted: 11/02/2015] [Indexed: 05/04/2023]
Abstract
The C4 pathway is a highly complex trait that increases photosynthetic efficiency in more than 60 plant lineages. Although the majority of C4 plants occupy disturbed, arid, and nutrient-poor habitats, some grow in high-nutrient, waterlogged conditions. One such example is Echinochloa glabrescens, which is an aggressive weed of rice paddies. We generated comprehensive transcriptome datasets for C4 E. glabrescens and C3 rice to identify genes associated with adaption to waterlogged, nutrient-replete conditions, but also used the data to better understand how C4 photosynthesis operates in these conditions. Leaves of E. glabrescens exhibited classical Kranz anatomy with lightly lobed mesophyll cells having low chloroplast coverage. As with rice and other hygrophytic C3 species, leaves of E. glabrescens accumulated a chloroplastic phosphoenolpyruvate carboxylase protein, albeit at reduced amounts relative to rice. The arid-grown species Setaria italica (C4) and Brachypodium distachyon (C3) were also found to accumulate chloroplastic phosphoenolpyruvate carboxylase. We identified a molecular signature associated with C4 photosynthesis in nutrient-replete, waterlogged conditions that is highly similar to those previously reported from C4 plants that grow in more arid conditions. We also identified a cohort of genes that have been subjected to a selective sweep associated with growth in paddy conditions. Overall, this approach highlights the value of using wild species such as weeds to identify adaptions to specific conditions associated with high-yielding crops in agriculture.
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Affiliation(s)
- Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Marek Szecowka
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Thomas E Hughes
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Richard Smith-Unna
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Steven Kelly
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Karen J Bailey
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Tammy L Sage
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Justin A Pachebat
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Richard Leegood
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (S.C., M.S., T.E.H., R.S.-U., J.A.P., J.M.H.);Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom (S.K.);Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom (K.J.B., R.L.); andDepartment of Ecology and Evolutionary Biology, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2 (T.L.S.)
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Stata M, Sage TL, Rennie TD, Khoshravesh R, Sultmanis S, Khaikin Y, Ludwig M, Sage RF. Mesophyll cells of C4 plants have fewer chloroplasts than those of closely related C3 plants. Plant Cell Environ 2014; 37:2587-2600. [PMID: 24689501 DOI: 10.1111/pce.12331] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/03/2014] [Accepted: 03/17/2014] [Indexed: 06/03/2023]
Abstract
The evolution of C(4) photosynthesis from C(3) ancestors eliminates ribulose bisphosphate carboxylation in the mesophyll (M) cell chloroplast while activating phosphoenolpyruvate (PEP) carboxylation in the cytosol. These changes may lead to fewer chloroplasts and different chloroplast positioning within M cells. To evaluate these possibilities, we compared chloroplast number, size and position in M cells of closely related C(3), C(3) -C(4) intermediate and C(4) species from 12 lineages of C(4) evolution. All C(3) species had more chloroplasts per M cell area than their C(4) relatives in high-light growth conditions. C(3) species also had higher chloroplast coverage of the M cell periphery than C(4) species, particularly opposite intercellular air spaces. In M cells from 10 of the 12 C(4) lineages, a greater fraction of the chloroplast envelope was pulled away from the plasmalemma in the C(4) species than their C(3) relatives. C(3) -C(4) intermediate species generally exhibited similar patterns as their C(3) relatives. We interpret these results to reflect adaptive shifts that facilitate efficient C(4) function by enhancing diffusive access to the site of primary carbon fixation in the cytosol. Fewer chloroplasts in C(4) M cells would also reduce shading of the bundle sheath chloroplasts, which also generate energy required by C(4) photosynthesis.
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Affiliation(s)
- Matt Stata
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada, M5S 3B2
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20
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Abstract
In this review, we examine how the specialized "Kranz" anatomy of C4 photosynthesis evolved from C3 ancestors. Kranz anatomy refers to the wreath-like structural traits that compartmentalize the biochemistry of C4 photosynthesis and enables the concentration of CO2 around Rubisco. A simplified version of Kranz anatomy is also present in the species that utilize C2 photosynthesis, where a photorespiratory glycine shuttle concentrates CO2 into an inner bundle-sheath-like compartment surrounding the vascular tissue. C2 Kranz is considered to be an intermediate stage in the evolutionary development of C4 Kranz, based on the intermediate branching position of C2 species in 14 evolutionary lineages of C4 photosynthesis. In the best-supported model of C4 evolution, Kranz anatomy in C2 species evolved from C3 ancestors with enlarged bundle sheath cells and high vein density. Four independent lineages have been identified where C3 sister species of C2 plants exhibit an increase in organelle numbers in the bundle sheath and enlarged bundle sheath cells. Notably, in all of these species, there is a pronounced shift of mitochondria to the inner bundle sheath wall, forming an incipient version of the C2 type of Kranz anatomy. This incipient version of C2 Kranz anatomy is termed proto-Kranz, and is proposed to scavenge photorespiratory CO2. By doing so, it may provide fitness benefits in hot environments, and thus represent a critical first stage of the evolution of both the C2 and C4 forms of Kranz anatomy.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, On M5S3B2 Canada
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, On M5S3B2 Canada
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, On M5S3B2 Canada
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21
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Oakley JC, Sultmanis S, Stinson CR, Sage TL, Sage RF. Comparative studies of C3 and C4 Atriplex hybrids in the genomics era: physiological assessments. J Exp Bot 2014; 65:3637-47. [PMID: 24675672 PMCID: PMC4085961 DOI: 10.1093/jxb/eru106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We crossed the C3 species Atriplex prostrata with the C4 species Atriplex rosea to produce F1 and F2 hybrids. All hybrids exhibited C3-like δ(13)C values, and had reduced rates of net CO2 assimilation compared with A. prostrata. The activities of the major C4 cycle enzymes PEP carboxylase, NAD-malic enzyme, and pyruvate-Pi dikinase in the hybrids were at most 36% of the C4 values. These results demonstrate the C4 metabolic cycle was disrupted in the hybrids. Photosynthetic CO2 compensation points (Г) of the hybrids were generally midway between the C3 and C4 values, and in most hybrids were accompanied by low, C3-like activities in one or more of the major C4 cycle enzymes. This supports the possibility that most hybrids use a photorespiratory glycine shuttle to concentrate CO2 into the bundle sheath cells. One hybrid exhibited a C4-like Г of 4 µmol mol(-1), indicating engagement of a C4 metabolic cycle. Consistently, this hybrid had elevated activities of all measured C4 cycle enzymes relative to the C3 parent; however, C3-like carbon isotope ratios indicate the low Г is mainly due to a photorespiratory glycine shuttle. The anatomy of the hybrids resembled that of C3-C4 intermediate species using a glycine shuttle to concentrate CO2 in the bundle sheath, and is further evidence that this physiology is the predominant, default condition of the F2 hybrids. Progeny of these hybrids should further segregate C3 and C4 traits and in doing so assist in the discovery of C4 genes using high-throughput methods of the genomics era.
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Affiliation(s)
- Jason C Oakley
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Corey R Stinson
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
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22
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Bissinger K, Khoshravesh R, Kotrade JP, Oakley J, Sage TL, Sage RF, Hartmann HEK, Kadereit G. Gisekia (Gisekiaceae): phylogenetic relationships, biogeography, and ecophysiology of a poorly known C₄ lineage in the Caryophyllales. Am J Bot 2014; 101:499-509. [PMID: 24638165 DOI: 10.3732/ajb.1300279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
PREMISE OF THE STUDY Gisekiaceae are a monogeneric family of the core Caryophyllales distributed in arid regions of Africa and Asia. The only widespread species of the genus, Gisekia pharnaceoides, performs C4 photosynthesis based on CO2 compensation point measurements. This study investigates the C4 syndrome and its evolution in Gisekia. The infrageneric relationships, distribution and bioclimatic preferences of Gisekia are also investigated. METHODS Leaf gas exchange characteristics, activity of Rubisco and major C4 cycle enzymes, and ultrastructural characteristics of mesophyll and bundle sheath cells are studied for Gisekia pharnaceoides. δ(13)C values and leaf anatomy are analyzed for all species. A dated molecular phylogeny of 39 accessions representing all species of Gisekiaceae and 14 representatives of closely related core Caryophyllales families is generated using four cp markers and ITS. The precise current distribution and bioclimatic niche of Gisekia is assessed on the basis of 520 georeferenced specimen localities. KEY RESULTS All traditionally recognized species of Gisekia are C4 plants with atriplicoid Kranz anatomy. Gisekia pharnaceoides uses the NAD-ME biochemical type. The molecular phylogeny demonstrated two East African clades nested within South African clades, demonstrating migration along the arid areas of eastern Africa during the Late Miocene/Pliocene Epochs. Most traditionally defined species are polyphyletic. CONCLUSIONS Gisekia represents an isolated C4 lineage within core Caryophyllales dating back to the Miocene Epoch and probably spread along the African arid corridor from a South African center of origin. The seven currently recognized species should be treated as one polymorphic species or species complex, Gisekia pharnaceoides agg.
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Affiliation(s)
- Kerstin Bissinger
- Institut für Allgemeine und Spezielle Botanik, Anselm-Franz-von Bentzel weg 9a, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
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23
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Ocampo G, Koteyeva NK, Voznesenskaya EV, Edwards GE, Sage TL, Sage RF, Columbus JT. Evolution of leaf anatomy and photosynthetic pathways in Portulacaceae. Am J Bot 2013; 100:2388-2402. [PMID: 24259525 DOI: 10.3732/ajb.1300094] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY Portulacaceae is a family with a remarkable diversity in photosynthetic pathways. This lineage not only has species with different C4 biochemistry (NADP-ME and NAD-ME types) and C3-C4 intermediacy, but also displays different leaf anatomical configurations. Here we addressed the evolutionary history of leaf anatomy and photosynthetic pathways in Portulacaceae. METHODS Photosynthetic pathways were assessed based on leaf anatomy and carbon isotope ratios. Information on the NADP-ME and NAD-ME C4 variants was obtained from the literature. The evolutionary relationships and trait evolution were estimated under a Bayesian framework, and divergence times were calibrated using the ages obtained in a previous study. KEY RESULTS C4 photosynthesis is the main pathway in Portulacaceae. One clade (Cryptopetala), however, includes species that have non-Kranz anatomy and C3 type isotope values, two of which are C3-C4 intermediates. The ancestral leaf anatomy for the family is uncertain. The analysis showed one origin of the C4 pathway, which was lost in the Cryptopetala clade. Nevertheless, when a second analysis was performed taking into account the limited number of species with NAD-ME and NADP-ME data, a secondary gain of the C4 pathway from a C3-C4 intermediate was inferred. CONCLUSIONS The C4 pathway evolved ca. 23 Myr in the Portulacaceae. The number of times that the pathway evolved in the family is uncertain. The diversity of leaf anatomical types and C4 biochemical variants suggest multiple independent origins of C4 photosynthesis. Evidence for a switch from C4 to C3-C4 intermediacy supports the hypothesis that intermediates represent a distinct successful strategy.
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Affiliation(s)
- Gilberto Ocampo
- Rancho Santa Ana Botanic Garden and Claremont Graduate University, 1500 North College Avenue, Claremont, California 91711 USA
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Sage TL, Busch FA, Johnson DC, Friesen PC, Stinson CR, Stata M, Sultmanis S, Rahman BA, Rawsthorne S, Sage RF. Initial events during the evolution of C4 photosynthesis in C3 species of Flaveria. Plant Physiol 2013; 163:1266-76. [PMID: 24064930 PMCID: PMC3813649 DOI: 10.1104/pp.113.221119] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 09/13/2013] [Indexed: 05/22/2023]
Abstract
The evolution of C4 photosynthesis in many taxa involves the establishment of a two-celled photorespiratory CO2 pump, termed C2 photosynthesis. How C3 species evolved C2 metabolism is critical to understanding the initial phases of C4 plant evolution. To evaluate early events in C4 evolution, we compared leaf anatomy, ultrastructure, and gas-exchange responses of closely related C3 and C2 species of Flaveria, a model genus for C4 evolution. We hypothesized that Flaveria pringlei and Flaveria robusta, two C3 species that are most closely related to the C2 Flaveria species, would show rudimentary characteristics of C2 physiology. Compared with less-related C3 species, bundle sheath (BS) cells of F. pringlei and F. robusta had more mitochondria and chloroplasts, larger mitochondria, and proportionally more of these organelles located along the inner cell periphery. These patterns were similar, although generally less in magnitude, than those observed in the C2 species Flaveria angustifolia and Flaveria sonorensis. In F. pringlei and F. robusta, the CO2 compensation point of photosynthesis was slightly lower than in the less-related C3 species, indicating an increase in photosynthetic efficiency. This could occur because of enhanced refixation of photorespired CO2 by the centripetally positioned organelles in the BS cells. If the phylogenetic positions of F. pringlei and F. robusta reflect ancestral states, these results support a hypothesis that increased numbers of centripetally located organelles initiated a metabolic scavenging of photorespired CO2 within the BS. This could have facilitated the formation of a glycine shuttle between mesophyll and BS cells that characterizes C2 photosynthesis.
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Affiliation(s)
| | | | - Daniel C. Johnson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Patrick C. Friesen
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Corey R. Stinson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Beshar A. Rahman
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Stephen Rawsthorne
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
| | - Rowan F. Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada (T.L.S., F.A.B., D.C.J., P.C.F., C.R.S., M.S., S.S., B.A.R., R.F.S.); and
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom (S.R.)
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Harsant J, Pavlovic L, Chiu G, Sultmanis S, Sage TL. High temperature stress and its effect on pollen development and morphological components of harvest index in the C3 model grass Brachypodium distachyon. J Exp Bot 2013; 64:2971-83. [PMID: 23771979 PMCID: PMC3697958 DOI: 10.1093/jxb/ert142] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The effect of high temperatures on harvest index (HI) and morphological components that contribute to HI was investigated in two lines (Bd21 and Bd21-3) of Brachypodium distachyon, a C3 grass recognized as a tractable plant, to address critical issues associated with enhancing cereal crop yields in the presence of global climate change. The results demonstrated that temperatures ≥32 °C eliminated HI. Reductions in yield at 32 °C were due primarily to declines in pollen viability, retention of pollen in anthers, and pollen germination, while abortion of microspores by the uninucleate stage that was correlated with abnormal tapetal development resulted in yield failure at 36 °C. Increasing temperatures from 24 to 32 °C resulted in reductions in tiller numbers but had no impact on axillary branch numbers per tiller. Grain developed at 24 and 28 °C primarily in tiller spikes, although spikes on axillary branches also formed grain. Grain quantity decreased in tiller spikes but increased in axillary branch spikes as temperatures rose from 24 to 28 °C. Differential patterns of axillary branching and floret development within spikelets between Bd21 and Bd21-3 resulted in higher grain yield in axillary branches of Bd21-3 at 28 °C. The response of male reproductive development and tiller branching patterns in B. distachyon to increasing temperatures mirrors that in other cereal crops, providing support for the use of this C3 grass in assessing the molecular control of HI in the presence of global warming.
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Affiliation(s)
- Jeffrey Harsant
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2
| | - Lazar Pavlovic
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2
| | - Greta Chiu
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2
| | - Tammy L. Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2
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Abstract
Photosynthetic carbon gain in plants using the C(3) photosynthetic pathway is substantially inhibited by photorespiration in warm environments, particularly in atmospheres with low CO(2) concentrations. Unlike C(4) plants, C(3) plants are thought to lack any mechanism to compensate for the loss of photosynthetic productivity caused by photorespiration. Here, for the first time, we demonstrate that the C(3) plants rice and wheat employ a specific mechanism to trap and reassimilate photorespired CO(2) . A continuous layer of chloroplasts covering the portion of the mesophyll cell periphery that is exposed to the intercellular air space creates a diffusion barrier for CO(2) exiting the cell. This facilitates the capture and reassimilation of photorespired CO(2) in the chloroplast stroma. In both species, 24-38% of photorespired and respired CO(2) were reassimilated within the cell, thereby boosting photosynthesis by 8-11% at ambient atmospheric CO(2) concentration and 17-33% at a CO(2) concentration of 200 µmol mol(-1) . Widespread use of this mechanism in tropical and subtropical C(3) plants could explain why the diversity of the world's C(3) flora, and dominance of terrestrial net primary productivity, was maintained during the Pleistocene, when atmospheric CO(2) concentrations fell below 200 µmol mol(-1) .
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Affiliation(s)
- Florian A Busch
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
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Khoshravesh R, Hossein A, Sage TL, Nordenstam B, Sage RF. Phylogeny and photosynthetic pathway distribution in Anticharis Endl. (Scrophulariaceae). J Exp Bot 2012; 63:5645-58. [PMID: 22945938 DOI: 10.1093/jxb/ers218] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
C(4) photosynthesis independently evolved >62 times, with the majority of origins within 16 dicot families. One origin occurs in the poorly studied genus Anticharis Endl. (Scrophulariaceae), which consists of ~10 species from arid regions of Africa and southwest Asia. Here, the photosynthetic pathway of 10 Anticharis species and one species from each of the sister genera Aptosimum and Peliostomum was identified using carbon isotope ratios (δ(13)C). The photosynthetic pathway was then mapped onto an internal transcribed spacer (ITS) phylogeny of Anticharis and its sister genera. Leaf anatomy was examined for nine Anticharis species and plants from Aptosimum and Peliostomum. Leaf ultrastructure, gas exchange, and enzyme distributions were assessed in Anticharis glandulosa collected in SE Iran. The results demonstrate that C(3) photosynthesis is the ancestral condition, with C(4) photosynthesis occurring in one clade containing four species. C(4) Anticharis species exhibit the atriplicoid type of C(4) leaf anatomy and the NAD-malic enzyme biochemical subtype. Six Anticharis species had C(3) or C(3)-C(4) δ(13)C values and branched at phylogenetic nodes that were sister to the C(4) clade. The rest of Anticharis species had enlarged bundle sheath cells, close vein spacing, and clusters of chloroplasts along the centripetal (inner) bundle sheath walls. These traits indicate that basal-branching Anticharis species are evolutionary intermediates between the C(3) and C(4) conditions. Anticharis appears to be an important new group in which to study the dynamics of C(4) evolution.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Plant Sciences, School of Biology, College of Sciences, University of Tehran PO Box 14155-6455, Tehran Iran
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Tolley BJ, Sage TL, Langdale JA, Hibberd JM. Individual maize chromosomes in the C(3) plant oat can increase bundle sheath cell size and vein density. Plant Physiol 2012; 159:1418-27. [PMID: 22675083 PMCID: PMC3425187 DOI: 10.1104/pp.112.200584] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
C(4) photosynthesis has evolved in at least 66 lineages within the angiosperms and involves alterations to the biochemistry, cell biology, and development of leaves. The characteristic "Kranz" anatomy of most C(4) leaves was discovered in the 1890s, but the genetic basis of these traits remains poorly defined. Oat × maize addition lines allow the effects of individual maize (Zea mays; C(4)) chromosomes to be investigated in an oat (Avena sativa; C(3)) genetic background. Here, we have determined the extent to which maize chromosomes can introduce C(4) characteristics into oat and have associated any C(4)-like changes with specific maize chromosomes. While there is no indication of a simultaneous change to C(4) biochemistry, leaf anatomy, and ultrastructure in any of the oat × maize addition lines, the C(3) oat leaf can be modified at multiple levels. Maize genes encoding phosphoenolpyruvate carboxylase, pyruvate, orthophosphate dikinase, and the 2'-oxoglutarate/malate transporter are expressed in oat and generate transcripts of the correct size. Three maize chromosomes independently cause increases in vein density, and maize chromosome 3 results in larger bundle sheath cells with increased cell wall lipid deposition in oat leaves. These data provide proof of principle that aspects of C(4) biology could be integrated into leaves of C(3) crops.
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Abstract
C(4) photosynthesis is one of the most convergent evolutionary phenomena in the biological world, with at least 66 independent origins. Evidence from these lineages consistently indicates that the C(4) pathway is the end result of a series of evolutionary modifications to recover photorespired CO(2) in environments where RuBisCO oxygenation is high. Phylogenetically informed research indicates that the repositioning of mitochondria in the bundle sheath is one of the earliest steps in C(4) evolution, as it may establish a single-celled mechanism to scavenge photorespired CO(2) produced in the bundle sheath cells. Elaboration of this mechanism leads to the two-celled photorespiratory concentration mechanism known as C(2) photosynthesis (commonly observed in C(3)-C(4) intermediate species) and then to C(4) photosynthesis following the upregulation of a C(4) metabolic cycle.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
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Muhaidat R, Sage TL, Frohlich MW, Dengler NG, Sage RF. Characterization of C₃--C₄ intermediate species in the genus Heliotropium L. (Boraginaceae): anatomy, ultrastructure and enzyme activity. Plant Cell Environ 2011; 34:1723-36. [PMID: 21631534 DOI: 10.1111/j.1365-3040.2011.02367.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Photosynthetic pathway characteristics were studied in nine species of Heliotropium (sensu lato, including Euploca), using assessments of leaf anatomy and ultrastructure, activities of PEP carboxylase and C₄ acid decarboxylases, and immunolocalization of ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) and the P-subunit of glycine decarboxylase (GDC). Heliotropium europaeum, Heliotropium calcicola and Heliotropium tenellum are C₃ plants, while Heliotropium texanum and Heliotropium polyphyllum are C₄ species. Heliotropium procumbens and Heliotropium karwinskyi are functionally C₃, but exhibit 'proto-Kranz' anatomy where bundle sheath (BS) cells are enlarged and mitochondria primarily occur along the centripetal (inner) wall of the BS cells; GDC is present throughout the leaf. Heliotropium convolvulaceum and Heliotropium greggii are C₃--C₄ intermediates, with Kranz-like enlargement of the BS cells, localization of mitochondria along the inner BS wall and a loss of GDC in the mesophyll (M) tissue. These C₃--C₄ species of Heliotropium probably shuttle photorespiratory glycine from the M to the BS tissue for decarboxylation. Heliotropium represents an important new model for studying C₄ evolution. Where existing models such as Flaveria emphasize diversification of C₃--C₄ intermediates, Heliotropium has numerous C₃ species expressing proto-Kranz traits that could represent a critical initial phase in the evolutionary origin of C₄ photosynthesis.
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Affiliation(s)
- Riyadh Muhaidat
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S3B2, Canada
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Sage TL, Sage RF, Vogan PJ, Rahman B, Johnson DC, Oakley JC, Heckel MA. The occurrence of C(2) photosynthesis in Euphorbia subgenus Chamaesyce (Euphorbiaceae). J Exp Bot 2011; 62:3183-95. [PMID: 21459765 DOI: 10.1093/jxb/err059] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
This study investigated whether Euphorbia subgenus Chamaesyce subsection Acutae contains C(3)-C(4) intermediate species utilizing C(2) photosynthesis, the process where photorespired CO(2) is concentrated into bundle sheath cells. Euphorbia species in subgenus Chamaesyce are generally C(4), but three species in subsection Acutae (E. acuta, E. angusta, and E. johnstonii) have C(3) isotopic ratios. Phylogenetically, subsection Acutae branches between basal C(3) clades within Euphorbia and the C(4) clade in subgenus Chamaesyce. Euphorbia angusta is C(3), as indicated by a photosynthetic CO(2) compensation point (Г) of 69 μmol mol(-1) at 30 °C, a lack of Kranz anatomy, and the occurrence of glycine decarboxylase in mesophyll tissues. Euphorbia acuta utilizes C(2) photosynthesis, as indicated by a Г of 33 μmol mol(-1) at 30 °C, Kranz-like anatomy with mitochondria restricted to the centripetal (inner) wall of the bundle sheath cells, and localization of glycine decarboxlyase to bundle sheath mitochondria. Low activities of PEP carboxylase, NADP malic enzyme, and NAD malic enzyme demonstrated no C(4) cycle activity occurs in E. acuta thereby classifying it as a Type I C(3)-C(4) intermediate. Kranz-like anatomy in E. johnstonii indicates it also utilizes C(2) photosynthesis. Given the phylogenetically intermediate position of E. acuta and E. johnstonii, these results support the hypothesis that C(2) photosynthesis is an evolutionary intermediate condition between C(3) and C(4) photosynthesis.
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Affiliation(s)
- Tammy L Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada
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Christin PA, Sage TL, Edwards EJ, Ogburn RM, Khoshravesh R, Sage RF. COMPLEX EVOLUTIONARY TRANSITIONS AND THE SIGNIFICANCE OF C3-C4 INTERMEDIATE FORMS OF PHOTOSYNTHESIS IN MOLLUGINACEAE. Evolution 2010; 65:643-60. [DOI: 10.1111/j.1558-5646.2010.01168.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sage TL, Sage RF. The functional anatomy of rice leaves: implications for refixation of photorespiratory CO2 and efforts to engineer C4 photosynthesis into rice. Plant Cell Physiol 2009; 50:756-72. [PMID: 19246459 DOI: 10.1093/pcp/pcp033] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
One mechanism to enhance global food stocks radically is to introduce C4 photosynthesis into C3 crops from warm climates, notably rice. To accomplish this, an understanding of leaf structure and function is essential. The chlorenchyma structure of rice and related warm-climate C3 grasses is distinct from that of cool temperate C3 grasses. In temperate C3 grasses, vacuoles occupy the majority of the cell, while chloroplasts, peroxisomes and mitochondria are pressed against the cell periphery. In rice, 66% of protoplast volume is occupied by chloroplasts, and chloroplasts/stromules cover >95% of the cell periphery. Mitochondria and peroxisomes occur in the cell interior and are intimately associated with chloroplasts/stromules. We hypothesize that the chlorenchyma architecture of rice enhances diffusive CO(2) conductance and maximizes scavenging of photorespired CO2. The extensive chloroplast/stromule sheath forces photorespired CO(2) to exit cells via the stroma, where it can be refixed by Rubisco. Deep cell lobing and small cell size, coupled with chloroplast sheaths, creates high surface area exposure of stroma to intercellular spaces, thereby enhancing mesophyll transfer conductance. In support of this, rice exhibits higher mesophyll transfer conductance, greater stromal CO2 content, lower CO2 compensation points at warm temperature and less oxygen sensitivity of photosynthesis than cool temperate grasses. Rice vein length per leaf, mesophyll thickness and intercellular space volume are intermediate between those of most C3 and C4 grasses, indicating that the introduction of Kranz anatomy into rice may not require radical changes in leaf anatomy; however, deep lobing of chlorenchyma cells may constrain efforts to engineer C4 photosynthesis into rice.
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Affiliation(s)
- Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada
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Sage TL, Hristova-Sarkovski K, Koehl V, Lyew J, Pontieri V, Bernhardt P, Weston P, Bagha S, Chiu G. Transmitting tissue architecture in basal-relictual angiosperms: Implications for transmitting tissue origins. Am J Bot 2009; 96:183-206. [PMID: 21628183 DOI: 10.3732/ajb.0800254] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Carpel transmitting tissue is a major floral innovation that is essential for angiosperm success. It facilitates the rapid adhesion, hydration, and growth of the male gametophyte to the female gametophyte. As well, it functions as a molecular screen to promote male gametophytic competition and species-specific recognition and compatibility. Here, we characterize the transmitting tissue extracellular matrix (ECM) and pollen tube growth in basal-relictual angiosperms and test the hypothesis that a freely flowing ECM (wet stigma) was ancestral to a cuticle-bound ECM (dry stigma). We demonstrate that the most recent common ancestor of extant angiosperms produced an ECM that was structurally and functionally equivalent to a dry stigma. Dry stigmas are composed of a cuticle and primary wall that contains compounds that facilitate the adhesion and growth of the male gametophyte. These compounds include methyl-esterified homogalacturonans, arabinogalactan-proteins, and lipids. We propose that transmitting tissue evolved in concert with an increase in cuticle permeability that resulted from modifications in the biosynthesis and secretion of fatty acids needed for cuticle construction. Increased cuticle permeability exposed the male gametophyte to pre-existing molecules that enabled rapid male gametophyte adhesion, hydration, and growth as well as species-specific recognition and compatibility.
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Affiliation(s)
- Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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Abstract
Higher water use efficiency (WUE) in C(4) plants may allow for greater xylem safety because transpiration rates are reduced. To evaluate this hypothesis, stem hydraulics and anatomy were compared in 16 C(3), C(3)-C(4) intermediate, C(4)-like and C(4) species in the genus Flaveria. The C(3) species had the highest leaf-specific conductivity (K(L)) compared with intermediate and C(4) species, with the perennial C(4) and C(4)-like species having the lowest K(L) values. Xylem-specific conductivity (K(S)) was generally highest in the C(3) species and lower in intermediate and C(4) species. Xylem vessels were shorter, narrower and more frequent in C(3)-C(4) intermediate, C(4)-like and C(4) species compared with C(3) species. WUE values were approximately double in the C(4)-like and C(4) species relative to the C(3)-C(4) and C(3) species. C(4)-like photosynthesis arose independently at least twice in Flaveria, and the trends in WUE and K(L) were consistent in both lineages. These correlated changes in WUE and K(L) indicate WUE increase promoted K(L) decline during C(4) evolution; however, any involvement of WUE comes late in the evolutionary sequence. C(3)-C(4) species exhibited reduced K(L) but little change in WUE compared to C(3) species, indicating that some reduction in hydraulic efficiency preceded increases in WUE.
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Affiliation(s)
- Ferit Kocacinar
- Faculty of Forestry, Kahramanmaras Sutcu Imam University, Merkez 46100 Kahramanmaras, Turkey
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Maeda H, Sage TL, Isaac G, Welti R, Dellapenna D. Tocopherols modulate extraplastidic polyunsaturated fatty acid metabolism in Arabidopsis at low temperature. Plant Cell 2008; 20:452-70. [PMID: 18314499 PMCID: PMC2276453 DOI: 10.1105/tpc.107.054718] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 01/04/2008] [Accepted: 02/09/2008] [Indexed: 05/20/2023]
Abstract
Tocopherols (vitamin E) are synthesized in plastids and have long been assumed to have essential functions restricted to these organelles. We previously reported that the vitamin e-deficient2 (vte2) mutant of Arabidopsis thaliana is defective in transfer cell wall development and photoassimilate transport at low temperature (LT). Here, we demonstrate that LT-treated vte2 has a distinct composition of polyunsaturated fatty acids (PUFAs): lower levels of linolenic acid (18:3) and higher levels of linoleic acid (18:2) compared with the wild type. Enhanced 18:3 oxidation was not involved, as indicated by the limited differences in oxidized lipid species between LT-treated vte2 and the wild type and by a lack of impact on the LT-induced vte2 phenotype in a vte2 fad3 fad7 fad8 quadruple mutant deficient in 18:3. PUFA changes in LT-treated vte2 occur primarily in phospholipids due to reduced conversion of dienoic to trienoic fatty acids in the endoplasmic reticulum (ER) pathway. Introduction of the ER fatty acid desaturase mutation, fad2, and to a lesser extent the plastidic fad6 mutation into the vte2 background suppressed the LT-induced vte2 phenotypes, including abnormal transfer cell wall development. These results provide biochemical and genetic evidence that plastid-synthesized tocopherols modulate ER PUFA metabolism early in the LT adaptation response of Arabidopsis.
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Affiliation(s)
- Hiroshi Maeda
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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Abstract
C(4) photosynthesis evolved multiple times in the Amaranthaceae s.s., but the C(4) evolutionary lineages are unclear because the photosynthetic pathway is unknown for most species of the family. To clarify the distribution of C(4) photosynthesis in the Amaranthaceae, we determined carbon isotope ratios of 607 species and mapped these onto a phylogeny determined from matK/trnK sequences. Approximately 28% of the Amaranthaceae species use the C(4) pathway. C(4) species occur in 10 genera-Aerva, Amaranthus, Blutaparon, Alternanthera, Froelichia, Lithophila, Guilleminea, Gomphrena, Gossypianthus, and Tidestromia. Aerva, Alternanthera, and Gomphrena contain both C(3) and C(4) species. In Aerva, 25% of the sampled species are C(4). In Alternanthera, 19.5% are C(4), while 89% of the Gomphrena species are C(4). Integration of isotope and matK/trnK data indicated C(4) photosynthesis evolved five times in the Amaranthaceae, specifically in Aerva, Alternanthera, Amaranthus, Tidestromia, and a lineage containing Froelichia, Blutaparon, Guilleminea, Gomphrena pro parte, and Lithophila. Aerva and Gomphrena are both polyphyletic with C(3) and C(4) species belonging to distinct clades. Alternanthera appears to be monophyletic with C(4) photosynthesis originating in a terminal sublineage of procumbent herbs. Alpine C(4) species were also identified in Alternanthera, Amaranthus, and Gomphrena, including one species (Gomphrena meyeniana) from 4600 m a.s.l.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2 Canada
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Lyew J, Li Z, Liang-Chen Y, Yi-Bo L, Sage TL. Pollen tube growth in association with a dry-type stigmatic transmitting tissue and extragynoecial compitum in the basal angiosperm Kadsura longipedunculata (Schisandraceae). Am J Bot 2007; 94:1170-82. [PMID: 21636484 DOI: 10.3732/ajb.94.7.1170] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Spatial features of pollen tube growth and the composition of the extracellular matrix (ECM) of transmitting tissue in carpels of Kadsura longipedunculata, a member of the basal angiosperm taxon Schisandraceae, were characterized to identify features of transmitting tissue that might have been important for pollen-carpel interactions during the early history of angiosperms. In addition to growing extracellularly along epidermal cells that make up stigmatic crests of individual carpels, pollen tubes grow on abaxial carpel epidermal cells between unfused carpels along an extragynoecial compitum to subsequently enter an adjacent carpel, a feature important for enhancing seed set in apocarpous species. Histo- and immunochemical data indicated that transmitting tissue ECM is not freely flowing as previously hypothesized. Rather, the ECM is similar to that of a dry-type stigma whereby a cuticular boundary with associated esterase activity confines a matrix containing methyl-esterified homogalacturonans. The Schisandraceae joins an increasing number of basal angiosperm taxa that have a transmitting tissue ECM similar to a dry-type stigma, thereby challenging traditional views that the ancestral pollen tube pathway was similar to a wet-type stigma covered with a freely flowing exudate. Dry-type stigmas are posited to provide tighter control over pollen capture, retention, and germination than wet-type stigmas.
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Affiliation(s)
- Joelle Lyew
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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Maeda H, Song W, Sage TL, DellaPenna D. Tocopherols play a crucial role in low-temperature adaptation and Phloem loading in Arabidopsis. Plant Cell 2006; 18:2710-32. [PMID: 17012603 PMCID: PMC1626601 DOI: 10.1105/tpc.105.039404] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
To test whether tocopherols (vitamin E) are essential in the protection against oxidative stress in plants, a series of Arabidopsis thaliana vitamin E (vte) biosynthetic mutants that accumulate different types and levels of tocopherols and pathway intermediates were analyzed under abiotic stress. Surprisingly subtle differences were observed between the tocopherol-deficient vte2 mutant and the wild type during high-light, salinity, and drought stresses. However, vte2, and to a lesser extent vte1, exhibited dramatic phenotypes under low temperature (i.e., increased anthocyanin levels and reduced growth and seed production). That these changes were independent of light level and occurred in the absence of photoinhibition or lipid peroxidation suggests that the mechanisms involved are independent of tocopherol functions in photoprotection. Compared with the wild type, vte1 and vte2 had reduced rates of photoassimilate export as early as 6 h into low-temperature treatment, increased soluble sugar levels by 60 h, and increased starch and reduced photosynthetic electron transport rate by 14 d. The rapid reduction in photoassimilate export in vte2 coincides with callose deposition exclusively in phloem parenchyma transfer cell walls adjacent to the companion cell/sieve element complex. Together, these results indicate that tocopherols have a more limited role in photoprotection than previously assumed but play crucial roles in low-temperature adaptation and phloem loading.
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Affiliation(s)
- Hiroshi Maeda
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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Abstract
FZO is a dynamin-related membrane-remodeling protein that mediates fusion between mitochondrial outer membranes in animals and fungi. We identified a single FZO-like protein in Arabidopsis, FZL, a new plant-specific member of the dynamin superfamily. FZL is targeted to chloroplasts and associated with thylakoid and envelope membranes as punctate structures. fzl knockout mutants have abnormalities in chloroplast and thylakoid morphology, including disorganized grana stacks and alterations in the relative proportions of grana and stroma thylakoids. Overexpression of FZL-GFP also conferred defects in thylakoid organization. Mutation of a conserved residue in the predicted FZL GTPase domain abolished both the punctate localization pattern and ability of FZL-GFP to complement the fzl mutant phenotype. FZL defines a new protein class within the dynamin superfamily of membrane-remodeling GTPases that regulates organization of the thylakoid network in plants. Notably, FZL levels do not affect mitochondrial morphology or ultrastructure, suggesting that mitochondrial morphology in plants is regulated by an FZO-independent mechanism.
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Affiliation(s)
- Hongbo Gao
- *Department of Plant Biology and
- Genetics Graduate Program, Michigan State University, East Lansing, MI 48824; and
| | - Tammy L. Sage
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S 3B2
| | - Katherine W. Osteryoung
- *Department of Plant Biology and
- To whom correspondence should be addressed at:
Department of Plant Biology, 166 Plant Biology Building, Michigan State University, East Lansing, MI 48824. E-mail:
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Sage TL, Price MV, Waser NM. Self-sterility in Ipomopsis aggregata (Polemoniaceae) is due to prezygotic ovule degeneration. Am J Bot 2006; 93:254-262. [PMID: 21646186 DOI: 10.3732/ajb.93.2.254] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Based on previous studies, extreme (>99%) self-sterility in scarlet gilia (Ipomopsis aggregata) appears to be involved in late-acting ovarian self-incompatibility (OSI). Here, we confirm this suggestion by comparing structural events that follow from cross- vs. self-pollinations of I. aggregata. Growth of cross- and self-pollen tubes in the style at 11 h and growth in the ovary at 24 h was equivalent. Nonetheless, by 24 h, cross-pollen effected a significantly higher percentage of both ovule penetration and fertilization. Ovules in self-pollinated flowers showed pronounced changes, including an absence of embryo sac expansion and reduced starch in the integument, by 11 h post-pollination, well before pollen tube entry into the ovary. In addition, the integumentary tapetum and adjacent 1-3 cell layers exhibited abnormal cell division, pronounced deposition of thick, pectin-rich cell walls, and cellular collapse. Ovules and embryo sacs from cross-pollinated flowers rarely showed such features. Developmental changes in ovules from self-pollinated flowers eventually resulted in integument and embryo sac collapse, a process not observed in ovules of unpollinated flowers. We suggest that OSI involves long-distance signaling between self-pollen or self-pollen tubes and carpel tissue that reduces availability of receptive ovules for fertilization before pollen tubes arrive in the ovary.
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Affiliation(s)
- Tammy L Sage
- Department of Botany, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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Hauser BA, Sun K, Oppenheimer DG, Sage TL. Changes in mitochondrial membrane potential and accumulation of reactive oxygen species precede ultrastructural changes during ovule abortion. Planta 2006; 223:492-9. [PMID: 16160848 DOI: 10.1007/s00425-005-0107-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2005] [Accepted: 08/01/2005] [Indexed: 05/04/2023]
Abstract
In many species, environmental stress reduces plant fertility. In Arabidopsis thaliana, a significant fraction of this reduction in plant fertility results from ovule abortion and embryo senescence. In this species, environmental conditions were identified that induced 94% of the developing ovules to either undergo stress-induced ovule abortion or embryo senescence (Sun et al. Plant Physiol 135:2358-2367, 2004). Following salt stress, physiological and anatomical changes were first detected in the female gametophyte of an aborting ovule. Two to four hours after a period of salt stress that induces most ovules to abort, the mitochondrial membrane potential dissipated. Subsequently, cells in the gametophyte accumulated reactive oxygen species, which are known to be molecules that promote programmed cell death (PCD). Because mitochondria often play an important role in PCD, these organelles were closely examined for changes in structure. Although the anatomy of mitochondria varied, reproducible changes in mitochondria structure were not observed. Nonetheless, other changes in ultrastructure were found. In some aborting gametophytes, concentric rings of endoplasmic reticulum were formed. In a fraction of the aborting ovules, cytoplasmic contents and organelles were invaginated into the vacuole. Even in cryofixed sections, many of these bodies appeared indistinct, which is consistent with the degradation of their contents.
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Affiliation(s)
- Bernard A Hauser
- Department of Botany, UF Genetics Institute, and Plant Molecular and Cellular Biology Program, University of Florida, 220 Bartram Hall, Gainesville, FL 32611-8526, USA.
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Nelson EA, Sage TL, Sage RF. Functional leaf anatomy of plants with crassulacean acid metabolism. Funct Plant Biol 2005; 32:409-419. [PMID: 32689143 DOI: 10.1071/fp04195] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 01/31/2005] [Indexed: 06/11/2023]
Abstract
Crassulacean acid metabolism (CAM) has evolved independently on dozens of occasions and is now found in over 7% of plant species. In this study, the leaf structure of a phylogenetically diverse assemblage of 18 CAM plants was compared with six C3 plants and four C4 plants to assess whether consistent anatomical patterns that may reflect functional constraints are present. CAM plants exhibited increased cell size and increased leaf and mesophyll thickness relative to C3 and C4 species. CAM species also exhibited reduced intercellular air space (IAS) and reduced length of mesophyll surface exposed to IAS per unit area (Lmes / area). The low volume of IAS and low exposure of mesophyll surface to IAS likely increases internal resistance to CO2 in CAM tissues. While this diffusional barrier may limit uptake of CO2 during Phases II and IV, carbon economy could be enhanced through the reduced loss of internal CO2 during all four phases of CAM.
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Affiliation(s)
- Elizabeth A Nelson
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Tammy L Sage
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
| | - Rowan F Sage
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2 Canada
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Sage TL, Sampson FB. Evidence for ovarian self-incompatibility as a cause of self-sterility in the relictual woody angiosperm, Pseudowintera axillaris (Winteraceae). Ann Bot 2003; 91:807-16. [PMID: 12730068 PMCID: PMC4242389 DOI: 10.1093/aob/mcg085] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Species within the genus Pseudowintera exhibit high rates of self-sterility. Self-sterility in the genus has been previously posited-but not confirmed-to be the result of late-acting ovarian self-incompatibility (OSI) functioning within nucellar tissue of the ovule to prevent self pollen tubes from entering the embryo sac. Structural and functional aspects of pollen-carpel interactions and early seed development following cross- and self-pollination were investigated in P. axillaris to determine the site, timing and possible mechanisms of self-sterility. No significant differences were observed between pollen tube growth, ovule penetration and double fertilization following cross- and self-pollination. Pollen tubes exhibited phasic growth in an extracellular matrix composed of proteins and carbohydrates, as well as arabinogalactans/arabinogalactan proteins. A uniform failure in embryo sac development prior to division of the zygote was apparent within 15 d following double fertilization by self gametes. Results indicate that SI mechanisms in P. axillaris do not prevent double fertilization from occurring. Instead, mechanisms of self-sterility affect post-zygotic development of the embryo sac. Although self-sterility may be attributed to inbreeding depression, given the post-zygotic nature of failure in embryo sac development, the possibility of late-acting OSI is discussed.
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Affiliation(s)
- Tammy L Sage
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2.
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Abstract
Plant dynamin-like proteins consist of a group of high molecular weight GTPase with diverse structural arrangements and cellular localizations. In addition, unlike animal dynamins, there was no evidence for the involvement of any plant dynamin-like protein in clathrin-mediated vesicle trafficking. In this study we demonstrate that ADL6 (Arabidopsis dynamin-like protein 6), due to its domain arrangement, behaves similarly to the animal dynamins. The association of ADL6 with clathrin-coated vesicles was demonstrated by co-fractionation and immunocytochemical studies. ADL6 also interacted via its C-terminus with gamma-adaptin, an adaptor protein of clathrin-coated vesicles. Our results suggest that ADL6 participates in clathrin-mediated vesicle trafficking originating from the Golgi. In addition, our studies demonstrate that ADL6 intrinsic GTPase activity is regulated by its association with acidic phospholipids and an SH3 (Src homology 3)-containing protein.
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Affiliation(s)
- Bernard C-H Lam
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
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Abstract
A group of plant AtSH3Ps (Arabidopsis thaliana SH3-containing proteins) involved in trafficking of clathrin-coated vesicles was identified from the GenBank database. These proteins contained predicted coiled-coil and Src homology 3 (SH3) domains that are similar to animal and yeast proteins involved in the formation, fission, and uncoating of clathrin-coated vesicles. Subcellular fractionation and immunolocalization studies confirmed the presence of AtSH3P1 in the endomembrane system. In particular, AtSH3P1 was localized on or adjacent to the plasma membrane and its associated vesicles, vesicles of the trans-Golgi network, and the partially coated reticulum. At all of these locations, AtSH3P1 colocalized with clathrin. Functionally, in vitro lipid binding assay demonstrated that AtSH3P1 bound to specific lipid groups known to accumulate at invaginated coated pits or coated vesicles. In addition, immunohistochemical studies and actin binding assays indicated that AtSH3P1 also may regulate vesicle trafficking along the actin cytoskeleton. Yeast complementation studies suggested that AtSH3Ps have similar functions to the yeast Rvs167p protein involved in endocytosis and actin arrangement. A novel interaction between AtSH3P1 and an auxilin-like protein was identified by yeast two-hybrid screening, immunolocalization, and an in vitro binding assay. The interaction was mediated through the SH3 domain of AtSH3P1 and a proline-rich domain of auxilin. The auxilin-like protein stimulated the uncoating of clathrin-coated vesicles by Hsc70, a reaction that appeared to be inhibited in the presence of AtSH3P1. Hence, AtSH3P1 may perform regulatory and/or scaffolding roles during the transition of fission and the uncoating of clathrin-coated vesicles.
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Affiliation(s)
- B C Lam
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada
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Lam BC, Sage TL, Bianchi F, Blumwald E. Role of SH3 domain-containing proteins in clathrin-mediated vesicle trafficking in Arabidopsis. Plant Cell 2001; 13:2499-512. [PMID: 11701884 PMCID: PMC139467 DOI: 10.1105/tpc.010279] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2001] [Accepted: 08/24/2001] [Indexed: 05/18/2023]
Abstract
A group of plant AtSH3Ps (Arabidopsis thaliana SH3-containing proteins) involved in trafficking of clathrin-coated vesicles was identified from the GenBank database. These proteins contained predicted coiled-coil and Src homology 3 (SH3) domains that are similar to animal and yeast proteins involved in the formation, fission, and uncoating of clathrin-coated vesicles. Subcellular fractionation and immunolocalization studies confirmed the presence of AtSH3P1 in the endomembrane system. In particular, AtSH3P1 was localized on or adjacent to the plasma membrane and its associated vesicles, vesicles of the trans-Golgi network, and the partially coated reticulum. At all of these locations, AtSH3P1 colocalized with clathrin. Functionally, in vitro lipid binding assay demonstrated that AtSH3P1 bound to specific lipid groups known to accumulate at invaginated coated pits or coated vesicles. In addition, immunohistochemical studies and actin binding assays indicated that AtSH3P1 also may regulate vesicle trafficking along the actin cytoskeleton. Yeast complementation studies suggested that AtSH3Ps have similar functions to the yeast Rvs167p protein involved in endocytosis and actin arrangement. A novel interaction between AtSH3P1 and an auxilin-like protein was identified by yeast two-hybrid screening, immunolocalization, and an in vitro binding assay. The interaction was mediated through the SH3 domain of AtSH3P1 and a proline-rich domain of auxilin. The auxilin-like protein stimulated the uncoating of clathrin-coated vesicles by Hsc70, a reaction that appeared to be inhibited in the presence of AtSH3P1. Hence, AtSH3P1 may perform regulatory and/or scaffolding roles during the transition of fission and the uncoating of clathrin-coated vesicles.
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Affiliation(s)
- B C Lam
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada
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Sage TL, Strumas F, Cole WW, Barrett SC. Differential ovule development following self- and cross-pollination: the basis of self-sterility in Narcissus triandrus (Amaryllidaceae). Am J Bot 1999. [PMID: 10371727 DOI: 10.2307/2656706] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Self-pollination results in significantly lower seed set than cross-pollination in tristylous Narcissus triandrus. We investigated structural and functional aspects of pollen-pistil interactions and ovule-seed development following cross- and self-pollination to assess the timing and mechanism of self-sterility. Ovule development within an ovary was asynchronous at anthesis. There were no significant differences in pollen tube behavior following cross- vs. self-pollination during the first 6 d of growth, regardless of style morph type. Double fertilization was significantly higher following cross- vs. self-pollination. Aborted embryo development was not detected following either pollination type up to seed maturity. Prior to pollen tube entry, a significantly greater number of ovules ceased to develop following self- vs. cross-pollination. These results indicate that self-sterility in N. triandrus operates prezygotically but does not involve differential pollen tube growth typical of many self-incompatibility (SI) systems. Instead, low seed set following self-pollination is caused by a reduction in ovule availability resulting from embryo sac degeneration. We hypothesize that this is due to the absence of a required stimulus for normal ovule development. If this is correct, current concepts of SI may need to be broadened to include a wider range of pollen-pistil interactions.
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Affiliation(s)
- T L Sage
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2
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