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Salesse-Smith CE, Lochocki EB, Doran L, Haas BE, Stutz SS, Long SP. Greater mesophyll conductance and leaf photosynthesis in the field through modified cell wall porosity and thickness via AtCGR3 expression in tobacco. PLANT BIOTECHNOLOGY JOURNAL 2024. [PMID: 38687118 DOI: 10.1111/pbi.14364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/02/2024] [Accepted: 04/11/2024] [Indexed: 05/02/2024]
Abstract
Mesophyll conductance (gm) describes the ease with which CO2 passes from the sub-stomatal cavities of the leaf to the primary carboxylase of photosynthesis, Rubisco. Increasing gm is suggested as a means to engineer increases in photosynthesis by increasing [CO2] at Rubisco, inhibiting oxygenation and accelerating carboxylation. Here, tobacco was transgenically up-regulated with Arabidopsis Cotton Golgi-related 3 (CGR3), a gene controlling methylesterification of pectin, as a strategy to increase CO2 diffusion across the cell wall and thereby increase gm. Across three independent events in tobacco strongly expressing AtCGR3, mesophyll cell wall thickness was decreased by 7%-13%, wall porosity increased by 75% and gm measured by carbon isotope discrimination increased by 28%. Importantly, field-grown plants showed an average 8% increase in leaf photosynthetic CO2 uptake. Up-regulating CGR3 provides a new strategy for increasing gm in dicotyledonous crops, leading to higher CO2 assimilation and a potential means to sustainable crop yield improvement.
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Affiliation(s)
- Coralie E Salesse-Smith
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Edward B Lochocki
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Lynn Doran
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Benjamin E Haas
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Samantha S Stutz
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Stephen P Long
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Departments of Plant Biology and of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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2
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Ludwig M, Hartwell J, Raines CA, Simkin AJ. The Calvin-Benson-Bassham cycle in C 4 and Crassulacean acid metabolism species. Semin Cell Dev Biol 2024; 155:10-22. [PMID: 37544777 DOI: 10.1016/j.semcdb.2023.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 07/03/2023] [Accepted: 07/25/2023] [Indexed: 08/08/2023]
Abstract
The Calvin-Benson-Bassham (CBB) cycle is the ancestral CO2 assimilation pathway and is found in all photosynthetic organisms. Biochemical extensions to the CBB cycle have evolved that allow the resulting pathways to act as CO2 concentrating mechanisms, either spatially in the case of C4 photosynthesis or temporally in the case of Crassulacean acid metabolism (CAM). While the biochemical steps in the C4 and CAM pathways are known, questions remain on their integration and regulation with CBB cycle activity. The application of omic and transgenic technologies is providing a more complete understanding of the biochemistry of C4 and CAM species and will also provide insight into the CBB cycle in these plants. As the global population increases, new solutions are required to increase crop yields and meet demands for food and other bioproducts. Previous work in C3 species has shown that increasing carbon assimilation through genetic manipulation of the CBB cycle can increase biomass and yield. There may also be options to improve photosynthesis in species using C4 photosynthesis and CAM through manipulation of the CBB cycle in these plants. This is an underexplored strategy and requires more basic knowledge of CBB cycle operation in these species to enable approaches for increased productivity.
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Affiliation(s)
- Martha Ludwig
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia.
| | - James Hartwell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | | | - Andrew J Simkin
- University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK; School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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Schreier TB, Müller KH, Eicke S, Faulkner C, Zeeman SC, Hibberd JM. Plasmodesmal connectivity in C 4 Gynandropsis gynandra is induced by light and dependent on photosynthesis. THE NEW PHYTOLOGIST 2024; 241:298-313. [PMID: 37882365 PMCID: PMC10952754 DOI: 10.1111/nph.19343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 09/28/2023] [Indexed: 10/27/2023]
Abstract
In leaves of C4 plants, the reactions of photosynthesis become restricted between two compartments. Typically, this allows accumulation of C4 acids in mesophyll (M) cells and subsequent decarboxylation in the bundle sheath (BS). In C4 grasses, proliferation of plasmodesmata between these cell types is thought to increase cell-to-cell connectivity to allow efficient metabolite movement. However, it is not known whether C4 dicotyledons also show this enhanced plasmodesmal connectivity and so whether this is a general requirement for C4 photosynthesis is not clear. How M and BS cells in C4 leaves become highly connected is also not known. We investigated these questions using 3D- and 2D-electron microscopy on the C4 dicotyledon Gynandropsis gynandra as well as phylogenetically close C3 relatives. The M-BS interface of C4 G. gynandra showed higher plasmodesmal frequency compared with closely related C3 species. Formation of these plasmodesmata was induced by light. Pharmacological agents that perturbed photosynthesis reduced the number of plasmodesmata, but this inhibitory effect could be reversed by the provision of exogenous sucrose. We conclude that enhanced formation of plasmodesmata between M and BS cells is wired to the induction of photosynthesis in C4 G. gynandra.
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Affiliation(s)
- Tina B. Schreier
- Department of Plant SciencesUniversity of CambridgeDowning StreetCambridgeCB1 3EAUK
- Present address:
Department of BiologyUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Karin H. Müller
- Cambridge Advanced Imaging Centre (CAIC)University of CambridgeDowning StreetCambridgeCB2 3DYUK
| | - Simona Eicke
- Institute of Molecular Plant BiologyETH ZurichZurichCH‐8092Switzerland
| | - Christine Faulkner
- Cell and Developmental BiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
| | - Samuel C. Zeeman
- Institute of Molecular Plant BiologyETH ZurichZurichCH‐8092Switzerland
| | - Julian M. Hibberd
- Department of Plant SciencesUniversity of CambridgeDowning StreetCambridgeCB1 3EAUK
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Arce Cubas L, Rodrigues Gabriel Sales C, Vath RL, Bernardo EL, Burnett AC, Kromdijk J. Lessons from relatives: C4 photosynthesis enhances CO2 assimilation during the low-light phase of fluctuations. PLANT PHYSIOLOGY 2023; 193:1073-1090. [PMID: 37335935 PMCID: PMC10517189 DOI: 10.1093/plphys/kiad355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/19/2023] [Accepted: 06/03/2023] [Indexed: 06/21/2023]
Abstract
Despite the global importance of species with C4 photosynthesis, there is a lack of consensus regarding C4 performance under fluctuating light. Contrasting hypotheses and experimental evidence suggest that C4 photosynthesis is either less or more efficient in fixing carbon under fluctuating light than the ancestral C3 form. Two main issues have been identified that may underly the lack of consensus: neglect of evolutionary distance between selected C3 and C4 species and use of contrasting fluctuating light treatments. To circumvent these issues, we measured photosynthetic responses to fluctuating light across 3 independent phylogenetically controlled comparisons between C3 and C4 species from Alloteropsis, Flaveria, and Cleome genera under 21% and 2% O2. Leaves were subjected to repetitive stepwise changes in light intensity (800 and 100 µmol m-2 s-1 photon flux density) with 3 contrasting durations: 6, 30, and 300 s. These experiments reconciled the opposing results found across previous studies and showed that (i) stimulation of CO2 assimilation in C4 species during the low-light phase was both stronger and more sustained than in C3 species; (ii) CO2 assimilation patterns during the high-light phase could be attributable to species or C4 subtype differences rather than photosynthetic pathway; and (iii) the duration of each light step in the fluctuation regime can strongly influence experimental outcomes.
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Affiliation(s)
- Lucίa Arce Cubas
- Department of Plant Sciences, University of Cambridge, Downing Street, CB2 3EA Cambridge, UK
| | | | - Richard L Vath
- Department of Plant Sciences, University of Cambridge, Downing Street, CB2 3EA Cambridge, UK
| | - Emmanuel L Bernardo
- Department of Plant Sciences, University of Cambridge, Downing Street, CB2 3EA Cambridge, UK
- Institute of Crop Science, College of Agriculture and Food Science, University of the Philippines Los Baños, College, Laguna 4031, Philippines
| | - Angela C Burnett
- Department of Plant Sciences, University of Cambridge, Downing Street, CB2 3EA Cambridge, UK
| | - Johannes Kromdijk
- Department of Plant Sciences, University of Cambridge, Downing Street, CB2 3EA Cambridge, UK
- Carl R Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Ermakova M, Woodford R, Taylor Z, Furbank RT, Belide S, von Caemmerer S. Faster induction of photosynthesis increases biomass and grain yield in glasshouse-grown transgenic Sorghum bicolor overexpressing Rieske FeS. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:1206-1216. [PMID: 36789455 DOI: 10.1111/pbi.14030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 02/08/2023] [Indexed: 05/27/2023]
Abstract
Sorghum is one of the most important crops providing food and feed in many of the world's harsher environments. Sorghum utilizes the C4 pathway of photosynthesis in which a biochemical carbon-concentrating mechanism results in high CO2 assimilation rates. Overexpressing the Rieske FeS subunit of the Cytochrome b6 f complex was previously shown to increase the rate of photosynthetic electron transport and stimulate CO2 assimilation in the model C4 plant Setaria viridis. To test whether productivity of C4 crops could be improved by Rieske overexpression, we created transgenic Sorghum bicolor Tx430 plants with increased Rieske content. The transgenic plants showed no marked changes in abundances of other photosynthetic proteins or chlorophyll content. The steady-state rates of electron transport and CO2 assimilation did not differ between the plants with increased Rieske abundance and control plants, suggesting that Cytochrome b6 f is not the only factor limiting electron transport in sorghum at high light and high CO2 . However, faster responses of non-photochemical quenching as well as an elevated quantum yield of Photosystem II and an increased CO2 assimilation rate were observed from the plants overexpressing Rieske during the photosynthetic induction, a process of activation of photosynthesis upon the dark-light transition. As a consequence, sorghum with increased Rieske content produced more biomass and grain when grown in glasshouse conditions. Our results indicate that increasing Rieske content has potential to boost productivity of sorghum and other C4 crops by improving the efficiency of light utilization and conversion to biomass through the faster induction of photosynthesis.
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Affiliation(s)
- Maria Ermakova
- Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, ACT, Australia
- School of Biological Sciences, Monash University, Melbourne, Vic, Australia
| | - Russell Woodford
- Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Zachary Taylor
- Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, ACT, Australia
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Brandenburg, Germany
| | - Robert T Furbank
- Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | | | - Susanne von Caemmerer
- Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, ACT, Australia
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Doug K. Allen. THE NEW PHYTOLOGIST 2023; 237:710-713. [PMID: 36601907 DOI: 10.1111/nph.18608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
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Arce Cubas L, Vath RL, Bernardo EL, Sales CRG, Burnett AC, Kromdijk J. Activation of CO 2 assimilation during photosynthetic induction is slower in C 4 than in C 3 photosynthesis in three phylogenetically controlled experiments. FRONTIERS IN PLANT SCIENCE 2023; 13:1091115. [PMID: 36684779 PMCID: PMC9848656 DOI: 10.3389/fpls.2022.1091115] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/05/2022] [Indexed: 05/31/2023]
Abstract
INTRODUCTION Despite their importance for the global carbon cycle and crop production, species with C4 photosynthesis are still somewhat understudied relative to C3 species. Although the benefits of the C4 carbon concentrating mechanism are readily observable under optimal steady state conditions, it is less clear how the presence of C4 affects activation of CO2 assimilation during photosynthetic induction. METHODS In this study we aimed to characterise differences between C4 and C3 photosynthetic induction responses by analysing steady state photosynthesis and photosynthetic induction in three phylogenetically linked pairs of C3 and C4 species from Alloteropsis, Flaveria, and Cleome genera. Experiments were conducted both at 21% and 2% O2 to evaluate the role of photorespiration during photosynthetic induction. RESULTS Our results confirm C4 species have slower activation of CO2 assimilation during photosynthetic induction than C3 species, but the apparent mechanism behind these differences varied between genera. Incomplete suppression of photorespiration was found to impact photosynthetic induction significantly in C4 Flaveria bidentis, whereas in the Cleome and Alloteropsis C4 species, delayed activation of the C3 cycle appeared to limit induction and a potentially supporting role for photorespiration was also identified. DISCUSSION The sheer variation in photosynthetic induction responses observed in our limited sample of species highlights the importance of controlling for evolutionary distance when comparing C3 and C4 photosynthetic pathways.
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Affiliation(s)
- Lucía Arce Cubas
- The University of Cambridge, Department of Plant Sciences, Cambridge, United Kingdom
| | - Richard L. Vath
- The University of Cambridge, Department of Plant Sciences, Cambridge, United Kingdom
| | - Emmanuel L. Bernardo
- The University of Cambridge, Department of Plant Sciences, Cambridge, United Kingdom
- University of the Philippines Los Baños, Institute of Crop Science, College of Agriculture and Food Science, College, Laguna, Philippines
| | | | - Angela C. Burnett
- The University of Cambridge, Department of Plant Sciences, Cambridge, United Kingdom
| | - Johannes Kromdijk
- The University of Cambridge, Department of Plant Sciences, Cambridge, United Kingdom
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