1
|
Stirbet A, Guo Y, Lazár D, Govindjee G. From leaf to multiscale models of photosynthesis: applications and challenges for crop improvement. PHOTOSYNTHESIS RESEARCH 2024; 161:21-49. [PMID: 38619700 DOI: 10.1007/s11120-024-01083-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 04/16/2024]
Abstract
To keep up with the growth of human population and to circumvent deleterious effects of global climate change, it is essential to enhance crop yield to achieve higher production. Here we review mathematical models of oxygenic photosynthesis that are extensively used, and discuss in depth a subset that accounts for diverse approaches providing solutions to our objective. These include models (1) to study different ways to enhance photosynthesis, such as fine-tuning antenna size, photoprotection and electron transport; (2) to bioengineer carbon metabolism; and (3) to evaluate the interactions between the process of photosynthesis and the seasonal crop dynamics, or those that have included statistical whole-genome prediction methods to quantify the impact of photosynthesis traits on the improvement of crop yield. We conclude by emphasizing that the results obtained in these studies clearly demonstrate that mathematical modelling is a key tool to examine different approaches to improve photosynthesis for better productivity, while effective multiscale crop models, especially those that also include remote sensing data, are indispensable to verify different strategies to obtain maximized crop yields.
Collapse
Affiliation(s)
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry, Ministry of Education Jiangnan University, Wuxi, 214122, China
| | - Dušan Lazár
- Department of Biophysics, Faculty of Science, Palacký Univesity, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, and the Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| |
Collapse
|
2
|
Bellasio C, Lundgren MR. The operation of PEPCK increases light harvesting plasticity in C 4 NAD-ME and NADP-ME photosynthetic subtypes: A theoretical study. PLANT, CELL & ENVIRONMENT 2024; 47:2288-2309. [PMID: 38494958 DOI: 10.1111/pce.14869] [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: 11/10/2022] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 03/19/2024]
Abstract
The repeated emergence of NADP-malic enzyme (ME), NAD-ME and phosphoenolpyruvate carboxykinase (PEPCK) subtypes of C4 photosynthesis are iconic examples of convergent evolution, which suggests that these biochemistries do not randomly assemble, but are instead specific adaptations resulting from unknown evolutionary drivers. Theoretical studies that are based on the classic biochemical understanding have repeatedly proposed light-use efficiency as a possible benefit of the PEPCK subtype. However, quantum yield measurements do not support this idea. We explore this inconsistency here via an analytical model that features explicit descriptions across a seamless gradient between C4 biochemistries to analyse light harvesting and dark photosynthetic metabolism. Our simulations show that the NADP-ME subtype, operated by the most productive crops, is the most efficient. The NAD-ME subtype has lower efficiency, but has greater light harvesting plasticity (the capacity to assimilate CO2 in the broadest combination of light intensity and spectral qualities). In both NADP-ME and NAD-ME backgrounds, increasing PEPCK activity corresponds to greater light harvesting plasticity but likely imposed a reduction in photosynthetic efficiency. We draw the first mechanistic links between light harvesting and C4 subtypes, providing the theoretical basis for future investigation.
Collapse
Affiliation(s)
- Chandra Bellasio
- Laboratory of Theoretical and Applied Crop Ecophysiology, School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
- Department of Chemistry, Biology ond Biotechnology, Università Degli Studi Di Perugia, Perugia, Italy
- Department of Biology, University of the Balearic Islands, Palma, Illes Balears, Spain
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | | |
Collapse
|
3
|
Bellasio C, Stuart-Williams H, Farquhar GD, Flexas J. C 4 maize and sorghum are more sensitive to rapid dehydration than C 3 wheat and sunflower. THE NEW PHYTOLOGIST 2023; 240:2239-2252. [PMID: 37814525 DOI: 10.1111/nph.19299] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/03/2023] [Indexed: 10/11/2023]
Abstract
The high productive potential, heat resilience, and greater water use efficiency of C4 over C3 plants attract considerable interest in the face of global warming and increasing population, but C4 plants are often sensitive to dehydration, questioning the feasibility of their wider adoption. To resolve the primary effect of dehydration from slower from secondary leaf responses originating within leaves to combat stress, we conducted an innovative dehydration experiment. Four crops grown in hydroponics were forced to a rapid yet controlled decrease in leaf water potential by progressively raising roots of out of the solution while measuring leaf gas exchange. We show that, under rapid dehydration, assimilation decreased more steeply in C4 maize and sorghum than in C3 wheat and sunflower. This reduction was due to a rise of nonstomatal limitation at triple the rate in maize and sorghum than in wheat and sunflower. Rapid reductions in assimilation were previously measured in numerous C4 species across both laboratory and natural conditions. Hence, we deduce that high sensitivity to rapid dehydration might stem from the disturbance of an intrinsic aspect of C4 bicellular photosynthesis. We posit that an obstruction to metabolite transport between mesophyll and bundle sheath cells could be the cause.
Collapse
Affiliation(s)
- Chandra Bellasio
- Laboratory of Theoretical and Applied Crop Ecophysiology, School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
- Biology of Plants Under Mediterranean Conditions, Department of Biology, University of the Balearic Islands, Illes Balears, Palma, 07122, Spain
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
| | | | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
| | - Jaume Flexas
- Biology of Plants Under Mediterranean Conditions, Department of Biology, University of the Balearic Islands, Illes Balears, Palma, 07122, Spain
| |
Collapse
|
4
|
Schlüter U, Bouvier JW, Guerreiro R, Malisic M, Kontny C, Westhoff P, Stich B, Weber APM. Brassicaceae display variation in efficiency of photorespiratory carbon-recapturing mechanisms. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6631-6649. [PMID: 37392176 PMCID: PMC10662225 DOI: 10.1093/jxb/erad250] [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: 12/22/2022] [Accepted: 06/30/2023] [Indexed: 07/03/2023]
Abstract
Carbon-concentrating mechanisms enhance the carboxylase efficiency of Rubisco by providing supra-atmospheric concentrations of CO2 in its surroundings. Beside the C4 photosynthesis pathway, carbon concentration can also be achieved by the photorespiratory glycine shuttle which requires fewer and less complex modifications. Plants displaying CO2 compensation points between 10 ppm and 40 ppm are often considered to utilize such a photorespiratory shuttle and are termed 'C3-C4 intermediates'. In the present study, we perform a physiological, biochemical, and anatomical survey of a large number of Brassicaceae species to better understand the C3-C4 intermediate phenotype, including its basic components and its plasticity. Our phylogenetic analysis suggested that C3-C4 metabolism evolved up to five times independently in the Brassicaceae. The efficiency of the pathway showed considerable variation. Centripetal accumulation of organelles in the bundle sheath was consistently observed in all C3-C4-classified taxa, indicating a crucial role for anatomical features in CO2-concentrating pathways. Leaf metabolite patterns were strongly influenced by the individual species, but accumulation of photorespiratory shuttle metabolites glycine and serine was generally observed. Analysis of phosphoenolpyruvate carboxylase activities suggested that C4-like shuttles have not evolved in the investigated Brassicaceae. Convergent evolution of the photorespiratory shuttle indicates that it represents a distinct photosynthesis type that is beneficial in some environments.
Collapse
Affiliation(s)
- Urte Schlüter
- Institute of Plant Biochemistry, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Jacques W Bouvier
- Institute of Plant Biochemistry, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Ricardo Guerreiro
- Institute for Quantitative Genetics and Genomics of Plants, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Milena Malisic
- Institute of Plant Biochemistry, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Carina Kontny
- Institute of Plant Biochemistry, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Philipp Westhoff
- Metabolomics and Metabolism Laboratory, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Benjamin Stich
- Institute for Quantitative Genetics and Genomics of Plants, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| |
Collapse
|
5
|
Bellasio C, Ermakova M. Reduction of bundle sheath size boosts cyclic electron flow in C 4 Setaria viridis acclimated to low light. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:1223-1237. [PMID: 35866447 PMCID: PMC9545969 DOI: 10.1111/tpj.15915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 05/22/2023]
Abstract
When C4 leaves are exposed to low light, the CO2 concentration in the bundle sheath (BS) cells decreases, causing an increase in photorespiration relative to assimilation, and a consequent reduction in biochemical efficiency. These effects can be mitigated by complex acclimation syndromes, which are of primary importance for crop productivity but are not well studied. We unveil an acclimation strategy involving the coordination of electron transport processes. First, we characterize the anatomy, gas exchange and electron transport of C4 Setaria viridis grown under low light. Through a purposely developed biochemical model, we resolve the photon fluxes and reaction rates to explain how the concerted acclimation strategies sustain photosynthetic efficiency. Our results show that a smaller BS in low-light-grown plants limited leakiness (the ratio of CO2 leak rate out of the BS over the rate of supply via C4 acid decarboxylation) but sacrificed light harvesting and ATP production. To counter ATP shortage and maintain high assimilation rates, plants facilitated light penetration through the mesophyll and upregulated cyclic electron flow in the BS. This shade tolerance mechanism, based on the optimization of light reactions, is possibly more efficient than the known mechanisms involving the rearrangement of carbon metabolism, and could potentially lead to innovative strategies for crop improvement.
Collapse
Affiliation(s)
- Chandra Bellasio
- Department of BiologyUniversity of the Balearic Islands07122PalmaIlles BalearsSpain
- Centre of Excellence for Translational Photosynthesis, Research School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Maria Ermakova
- Centre of Excellence for Translational Photosynthesis, Research School of BiologyThe Australian National UniversityActonACT2601Australia
| |
Collapse
|
6
|
Koyro HW, Huchzermeyer B. From Soil Amendments to Controlling Autophagy: Supporting Plant Metabolism under Conditions of Water Shortage and Salinity. PLANTS 2022; 11:plants11131654. [PMID: 35807605 PMCID: PMC9269222 DOI: 10.3390/plants11131654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/03/2022] [Accepted: 06/16/2022] [Indexed: 11/30/2022]
Abstract
Crop resistance to environmental stress is a major issue. The globally increasing land degradation and desertification enhance the demand on management practices to balance both food and environmental objectives, including strategies that tighten nutrient cycles and maintain yields. Agriculture needs to provide, among other things, future additional ecosystem services, such as water quantity and quality, runoff control, soil fertility maintenance, carbon storage, climate regulation, and biodiversity. Numerous research projects have focused on the food–soil–climate nexus, and results were summarized in several reviews during the last decades. Based on this impressive piece of information, we have selected only a few aspects with the intention of studying plant–soil interactions and methods for optimization. In the short term, the use of soil amendments is currently attracting great interest to cover the current demand in agriculture. We will discuss the impact of biochar at water shortage, and plant growth promoting bacteria (PGPB) at improving nutrient supply to plants. In this review, our focus is on the interplay of both soil amendments on primary reactions of photosynthesis, plant growth conditions, and signaling during adaptation to environmental stress. Moreover, we aim at providing a general overview of how dehydration and salinity affect signaling in cells. With the use of the example of abscisic acid (ABA) and ethylene, we discuss the effects that can be observed when biochar and PGPB are used in the presence of stress. The stress response of plants is a multifactorial trait. Nevertheless, we will show that plants follow a general concept to adapt to unfavorable environmental conditions in the short and long term. However, plant species differ in the upper and lower regulatory limits of gene expression. Therefore, the presented data may help in the identification of traits for future breeding of stress-resistant crops. One target for breeding could be the removal and efficient recycling of damaged as well as needless compounds and structures. Furthermore, in this context, we will show that autophagy can be a useful goal of breeding measures, since the recycling of building blocks helps the cells to overcome a period of imbalanced substrate supply during stress adjustment.
Collapse
Affiliation(s)
- Hans-Werner Koyro
- Institute of Plantecology, Justus-Liebig-University, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
- Correspondence:
| | - Bernhard Huchzermeyer
- Institute of Botany, Leibniz Universitaet Hannover, Herrenhaeuser Str. 2, 30416 Hannover, Germany; or
- AK Biotechnology, VDI-BV-Hannover, Hanomagstr. 12, 30449 Hannover, Germany
| |
Collapse
|
7
|
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. THE NEW PHYTOLOGIST 2022; 233:1083-1096. [PMID: 34669188 DOI: 10.1111/nph.17818] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [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.
Collapse
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
| |
Collapse
|
8
|
Johnson JE, Field CB, Berry JA. The limiting factors and regulatory processes that control the environmental responses of C 3, C 3-C 4 intermediate, and C 4 photosynthesis. Oecologia 2021; 197:841-866. [PMID: 34714387 PMCID: PMC8591018 DOI: 10.1007/s00442-021-05062-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/07/2021] [Indexed: 11/28/2022]
Abstract
Here, we describe a model of C3, C3-C4 intermediate, and C4 photosynthesis that is designed to facilitate quantitative analysis of physiological measurements. The model relates the factors limiting electron transport and carbon metabolism, the regulatory processes that coordinate these metabolic domains, and the responses to light, carbon dioxide, and temperature. It has three unique features. First, mechanistic expressions describe how the cytochrome b6f complex controls electron transport in mesophyll and bundle sheath chloroplasts. Second, the coupling between the mesophyll and bundle sheath expressions represents how feedback regulation of Cyt b6f coordinates electron transport and carbon metabolism. Third, the temperature sensitivity of Cyt b6f is differentiated from that of the coupling between NADPH, Fd, and ATP production. Using this model, we present simulations demonstrating that the light dependence of the carbon dioxide compensation point in C3-C4 leaves can be explained by co-occurrence of light saturation in the mesophyll and light limitation in the bundle sheath. We also present inversions demonstrating that population-level variation in the carbon dioxide compensation point in a Type I C3-C4 plant, Flaveria chloraefolia, can be explained by variable allocation of photosynthetic capacity to the bundle sheath. These results suggest that Type I C3-C4 intermediate plants adjust pigment and protein distributions to optimize the glycine shuttle under different light and temperature regimes, and that the malate and aspartate shuttles may have originally functioned to smooth out the energy supply and demand associated with the glycine shuttle. This model has a wide range of potential applications to physiological, ecological, and evolutionary questions.
Collapse
Affiliation(s)
- Jennifer E Johnson
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA.
| | - Christopher B Field
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA
- Stanford Woods Institute for the Environment, Stanford University, 473 Via Ortega, Stanford, CA, 94305, USA
| | - Joseph A Berry
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA
| |
Collapse
|
9
|
Patron NJ. Beyond natural: synthetic expansions of botanical form and function. THE NEW PHYTOLOGIST 2020; 227:295-310. [PMID: 32239523 PMCID: PMC7383487 DOI: 10.1111/nph.16562] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/03/2020] [Indexed: 05/05/2023]
Abstract
Powered by developments that enabled genome-scale investigations, systems biology emerged as a field aiming to understand how phenotypes emerge from network functions. These advances fuelled a new engineering discipline focussed on synthetic reconstructions of complex biological systems with the goal of predictable rational design and control. Initially, progress in the nascent field of synthetic biology was slow due to the ad hoc nature of molecular biology methods such as cloning. The application of engineering principles such as standardisation, together with several key technical advances, enabled a revolution in the speed and accuracy of genetic manipulation. Combined with mathematical and statistical modelling, this has improved the predictability of engineering biological systems of which nonlinearity and stochasticity are intrinsic features leading to remarkable achievements in biotechnology as well as novel insights into biological function. In the past decade, there has been slow but steady progress in establishing foundations for synthetic biology in plant systems. Recently, this has enabled model-informed rational design to be successfully applied to the engineering of plant gene regulation and metabolism. Synthetic biology is now poised to transform the potential of plant biotechnology. However, reaching full potential will require conscious adjustments to the skillsets and mind sets of plant scientists.
Collapse
Affiliation(s)
- Nicola J. Patron
- Engineering BiologyEarlham InstituteNorwich Research Park, NorwichNorfolkNR4 7UZUK
| |
Collapse
|
10
|
Ermakova M, Danila FR, Furbank RT, von Caemmerer S. On the road to C 4 rice: advances and perspectives. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:940-950. [PMID: 31596523 PMCID: PMC7065233 DOI: 10.1111/tpj.14562] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 09/27/2019] [Accepted: 10/03/2019] [Indexed: 05/18/2023]
Abstract
The international C4 rice consortium aims to introduce into rice a high capacity photosynthetic mechanism, the C4 pathway, to increase yield. The C4 pathway is characterised by a complex combination of biochemical and anatomical specialisation that ensures high CO2 partial pressure at RuBisCO sites in bundle sheath (BS) cells. Here we report an update of the progress of the C4 rice project. Since its inception in 2008 there has been an exponential growth in synthetic biology and molecular tools. Golden Gate cloning and synthetic promoter systems have facilitated gene building block approaches allowing multiple enzymes and metabolite transporters to be assembled and expressed from single gene constructs. Photosynthetic functionalisation of the BS in rice remains an important step and there has been some success overexpressing transcription factors in the cytokinin signalling network which influence chloroplast volume. The C4 rice project has rejuvenated the research interest in C4 photosynthesis. Comparative anatomical studies now point to critical features essential for the design. So far little attention has been paid to the energetics. C4 photosynthesis has a greater ATP requirement, which is met by increased cyclic electron transport in BS cells. We hypothesise that changes in energy statues may drive this increased capacity for cyclic electron flow without the need for further modification. Although increasing vein density will ultimately be necessary for high efficiency C4 rice, our modelling shows that small amounts of C4 photosynthesis introduced around existing veins could already provide benefits of increased photosynthesis on the road to C4 rice.
Collapse
Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Florence R. Danila
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| |
Collapse
|
11
|
Bellasio C. A generalised dynamic model of leaf-level C 3 photosynthesis combining light and dark reactions with stomatal behaviour. PHOTOSYNTHESIS RESEARCH 2019; 141:99-118. [PMID: 30471008 DOI: 10.1007/s11120-018-0601-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 10/27/2018] [Indexed: 05/16/2023]
Abstract
Global food demand is rising, impelling us to develop strategies for improving the efficiency of photosynthesis. Classical photosynthesis models based on steady-state assumptions are inherently unsuitable for assessing biochemical and stomatal responses to rapid variations in environmental drivers. To identify strategies to increase photosynthetic efficiency, we need models that account for the timing of CO2 assimilation responses to dynamic environmental stimuli. Herein, I present a dynamic process-based photosynthetic model for C3 leaves. The model incorporates both light and dark reactions, coupled with a hydro-mechanical model of stomatal behaviour. The model achieved a stable and realistic rate of light-saturated CO2 assimilation and stomatal conductance. Additionally, it replicated complete typical assimilatory response curves (stepwise change in CO2 and light intensity at different oxygen levels) featuring both short lag times and full photosynthetic acclimation. The model also successfully replicated transient responses to changes in light intensity (light flecks), CO2 concentration, and atmospheric oxygen concentration. This dynamic model is suitable for detailed ecophysiological studies and has potential for superseding the long-dominant steady-state approach to photosynthesis modelling. The model runs as a stand-alone workbook in Microsoft® Excel® and is freely available to download along with a video tutorial.
Collapse
Affiliation(s)
- Chandra Bellasio
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia.
- University of the Balearic Islands, 07122, Palma, Illes Balears, Spain.
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino, 50019, Florence, Italy.
| |
Collapse
|
12
|
Bellasio C, Farquhar GD. A leaf-level biochemical model simulating the introduction of C 2 and C 4 photosynthesis in C 3 rice: gains, losses and metabolite fluxes. THE NEW PHYTOLOGIST 2019; 223:150-166. [PMID: 30859576 DOI: 10.1111/nph.15787] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/03/2019] [Indexed: 05/21/2023]
Abstract
This work aims at developing an adequate theoretical basis for comparing assimilation of the ancestral C3 pathway with CO2 concentrating mechanisms (CCM) that have evolved to reduce photorespiratory yield losses. We present a novel model for C3 , C2 , C2 + C4 and C4 photosynthesis simulating assimilatory metabolism, energetics and metabolite traffic at the leaf level. It integrates a mechanistic description of light reactions to simulate ATP and NADPH production, and a variable engagement of cyclic electron flow. The analytical solutions are compact and thus suitable for larger scale simulations. Inputs were derived with a comprehensive gas-exchange experiment. We show trade-offs in the operation of C4 that are in line with ecophysiological data. C4 has the potential to increase assimilation over C3 at high temperatures and light intensities, but this benefit is reversed under low temperatures and light. We apply the model to simulate the introduction of progressively complex levels of CCM into C3 rice, which feeds > 3.5 billion people. Increasing assimilation will require considerable modifications such as expressing the NAD(P)H Dehydrogenase-like complex and upregulating cyclic electron flow, enlarging the bundle sheath, and expressing suitable transporters to allow adequate metabolite traffic. The simpler C2 rice may be a desirable alternative.
Collapse
Affiliation(s)
- Chandra Bellasio
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
- University of the Balearic Islands, Palma, Illes Balears, 07122, Spain
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino, Florence, 50019, Italy
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
| |
Collapse
|
13
|
Cacefo V, Ribas AF, Zilliani RR, Neris DM, Domingues DS, Moro AL, Vieira LGE. Decarboxylation mechanisms of C4 photosynthesis in Saccharum spp.: increased PEPCK activity under water-limiting conditions. BMC PLANT BIOLOGY 2019; 19:144. [PMID: 30991938 PMCID: PMC6469216 DOI: 10.1186/s12870-019-1745-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/28/2019] [Indexed: 05/22/2023]
Abstract
BACKGROUND C4 plants have been classified into three subtypes based on the enzymes used to decarboxylate C4 acids in the bundle sheath cells (NADP-ME, NAD-ME and PEPCK pathways). Evidences indicate that, depending on environmental factors, C4 plants may exhibit a certain degree of flexibility in the use of the decarboxylation mechanisms. In this context, the objective was to extend the knowledge on the degree of flexibility between the pathways of decarboxylation in sugarcane, a NADP-ME species, at different levels of water deficit. RESULTS An experiment was carried out with two cultivars - RB92579 (tolerant to water deficit) and SP80-3280 (susceptible to water deficit) subjected to moderate level (- 1.5 to - 1.8 MPa), severe level (below - 2.0 MPa) and recovery (48 h after rehydration) and changes in the activities of the enzymes involved in the three C4 mechanisms and in gene expression were investigated. Our results showed that sugarcane uses the PEPCK pathway as a decarboxylation mechanism in addition to the NADP-ME, which was more evident under water deficit conditions for both cultivars. CONCLUSIONS The results obtained here, show that sugarcane increases the use of the PEPCK pathway as a decarboxylation mechanism, in addition to the NADP-ME pathway, under conditions of water deficit, particularly in the tolerant cultivar.
Collapse
Affiliation(s)
- Viviane Cacefo
- Centro de Estudos em Ecofisiologia Vegetal do Oeste Paulista (CEVOP), Universidade do Oeste Paulista (UNOESTE), Rodovia Raposo Tavares, Km 572, CEP, Presidente Prudente, SP 19067-175 Brazil
| | - Alessandra Ferreira Ribas
- Agronomy Graduate Program, Universidade do Oeste Paulista (UNOESTE), Rodovia Raposo Tavares, Km 572, CEP, Presidente Prudente, SP 19067-175 Brazil
| | - Rafael Rebes Zilliani
- Centro de Estudos em Ecofisiologia Vegetal do Oeste Paulista (CEVOP), Universidade do Oeste Paulista (UNOESTE), Rodovia Raposo Tavares, Km 572, CEP, Presidente Prudente, SP 19067-175 Brazil
| | - Daniel Moreira Neris
- Centro de Estudos em Ecofisiologia Vegetal do Oeste Paulista (CEVOP), Universidade do Oeste Paulista (UNOESTE), Rodovia Raposo Tavares, Km 572, CEP, Presidente Prudente, SP 19067-175 Brazil
| | - Douglas Silva Domingues
- Departamento de Botânica, Instituto de Biociências de Rio Claro, Universidade Estadual Paulista (UNESP), Avenida 24-A, 1515, CEP, Rio Claro, SP 13506-900 Brazil
| | - Adriana Lima Moro
- Centro de Estudos em Ecofisiologia Vegetal do Oeste Paulista (CEVOP), Universidade do Oeste Paulista (UNOESTE), Rodovia Raposo Tavares, Km 572, CEP, Presidente Prudente, SP 19067-175 Brazil
| | - Luiz Gonzaga Esteves Vieira
- Agronomy Graduate Program, Universidade do Oeste Paulista (UNOESTE), Rodovia Raposo Tavares, Km 572, CEP, Presidente Prudente, SP 19067-175 Brazil
| |
Collapse
|
14
|
Quirk J, Bellasio C, Johnson DA, Osborne CP, Beerling DJ. C
4
savanna grasses fail to maintain assimilation in drying soil under low CO
2
compared with C
3
trees despite lower leaf water demand. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13240] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Joe Quirk
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| | - Chandra Bellasio
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
- Research School of Biology Australian National University Acton Australian Capital Territory Australia
- University of the Balearic Islands Palma, Illes Balears Spain
- Trees and Timber Institute National Research Council of Italy Sesto Fiorentino, Florence Italy
| | - David A. Johnson
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| | - Colin P. Osborne
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| | - David J. Beerling
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| |
Collapse
|
15
|
Bellasio C, Quirk J, Beerling DJ. Stomatal and non-stomatal limitations in savanna trees and C 4 grasses grown at low, ambient and high atmospheric CO 2. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 274:181-192. [PMID: 30080602 DOI: 10.1016/j.plantsci.2018.05.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 05/07/2023]
Abstract
By the end of the century, atmospheric CO2 concentration ([CO2]a) could reach 800 ppm, having risen from ∼200 ppm ∼24 Myr ago. Carbon dioxide enters plant leaves through stomata that limit CO2 diffusion and assimilation, imposing stomatal limitation (LS). Other factors limiting assimilation are collectively called non-stomatal limitations (LNS). C4 photosynthesis concentrates CO2 around Rubisco, typically reducing LS. C4-dominated savanna grasslands expanded under low [CO2]a and are metastable ecosystems where the response of trees and C4 grasses to rising [CO2]a will determine shifting vegetation patterns. How LS and LNS differ between savanna trees and C4 grasses under different [CO2]a will govern the responses of CO2 fixation and plant cover to [CO2]a - but quantitative comparisons are lacking. We measured assimilation, within soil wetting-drying cycles, of three C3 trees and three C4 grasses grown at 200, 400 or 800 ppm [CO2]a. Using assimilation-response curves, we resolved LS and LNS and show that rising [CO2]a alleviated LS, particularly for the C3 trees, but LNS was unaffected and remained substantially higher for the grasses across all [CO2]a treatments. Because LNS incurs higher metabolic costs and recovery compared with LS, our findings indicate that C4 grasses will be comparatively disadvantaged as [CO2]a rises.
Collapse
Affiliation(s)
- Chandra Bellasio
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK; Research School of Biology, Australian National University, Acton, ACT, 2601 Australia; University of the Balearic Islands 07122 Palma, Illes Balears, Spain; Trees and Timber institute, National Research Council of Italy, 50019 Sesto Fiorentino (Florence), Italy.
| | - Joe Quirk
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - David J Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| |
Collapse
|
16
|
Yin X, Struik PC. The energy budget in C 4 photosynthesis: insights from a cell-type-specific electron transport model. THE NEW PHYTOLOGIST 2018; 218:986-998. [PMID: 29520959 PMCID: PMC5947737 DOI: 10.1111/nph.15051] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/16/2018] [Indexed: 05/18/2023]
Abstract
Extra ATP required in C4 photosynthesis for the CO2 -concentrating mechanism probably comes from cyclic electron transport (CET). As metabolic ATP : NADPH requirements in mesophyll (M) and bundle-sheath (BS) cells differ among C4 subtypes, the subtypes may differ in the extent to which CET operates in these cells. We present an analytical model for cell-type-specific CET and linear electron transport. Modelled NADPH and ATP production were compared with requirements. For malic-enzyme (ME) subtypes, c. 50% of electron flux is CET, occurring predominantly in BS cells for standard NADP-ME species, but in a ratio of c. 6 : 4 in BS : M cells for NAD-ME species. Some C4 acids follow a secondary decarboxylation route, which is obligatory, in the form of 'aspartate-malate', for the NADP-ME subtype, but facultative, in the form of phosphoenolpyruvate-carboxykinase (PEP-CK), for the NAD-ME subtype. The percentage for secondary decarboxylation is c. 25% and that for 3-phosphoglycerate reduction in BS cells is c. 40%; but these values vary with species. The 'pure' PEP-CK type is unrealistic because its is impossible to fulfil ATP : NADPH requirements in BS cells. The standard PEP-CK subtype requires negligible CET, and thus has the highest intrinsic quantum yields and deserves further studies in the context of improving canopy productivity.
Collapse
Affiliation(s)
- Xinyou Yin
- Department of Plant SciencesCentre for Crop Systems AnalysisWageningen University & ResearchPO Box 4306700 AKWageningenthe Netherlands
| | - Paul C. Struik
- Department of Plant SciencesCentre for Crop Systems AnalysisWageningen University & ResearchPO Box 4306700 AKWageningenthe Netherlands
| |
Collapse
|
17
|
Bellasio C, Quirk J, Buckley TN, Beerling DJ. A Dynamic Hydro-Mechanical and Biochemical Model of Stomatal Conductance for C 4 Photosynthesis. PLANT PHYSIOLOGY 2017; 175:104-119. [PMID: 28751312 PMCID: PMC5580762 DOI: 10.1104/pp.17.00666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/24/2017] [Indexed: 05/10/2023]
Abstract
C4 plants are major grain (maize [Zea mays] and sorghum [Sorghum bicolor]), sugar (sugarcane [Saccharum officinarum]), and biofuel (Miscanthus spp.) producers and contribute ∼20% to global productivity. Plants lose water through stomatal pores in order to acquire CO2 (assimilation [A]) and control their carbon-for-water balance by regulating stomatal conductance (gS). The ability to mechanistically predict gS and A in response to atmospheric CO2, water availability, and time is critical for simulating stomatal control of plant-atmospheric carbon and water exchange under current, past, or future environmental conditions. Yet, dynamic mechanistic models for gS are lacking, especially for C4 photosynthesis. We developed and coupled a hydromechanical model of stomatal behavior with a biochemical model of C4 photosynthesis, calibrated using gas-exchange measurements in maize, and extended the coupled model with time-explicit functions to predict dynamic responses. We demonstrated the wider applicability of the model with three additional C4 grass species in which interspecific differences in stomatal behavior could be accounted for by fitting a single parameter. The model accurately predicted steady-state responses of gS to light, atmospheric CO2 and oxygen, soil drying, and evaporative demand as well as dynamic responses to light intensity. Further analyses suggest that the effect of variable leaf hydraulic conductance is negligible. Based on the model, we derived a set of equations suitable for incorporation in land surface models. Our model illuminates the processes underpinning stomatal control in C4 plants and suggests that the hydraulic benefits associated with fast stomatal responses of C4 grasses may have supported the evolution of C4 photosynthesis.
Collapse
Affiliation(s)
- Chandra Bellasio
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Trees and Timber Institute, National Research Council of Italy, 50019 Florence, Italy
| | - Joe Quirk
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Thomas N Buckley
- Sydney Institute of Agriculture, University of Sydney, Narrabri, New South Wales 2390, Australia
| | - David J Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| |
Collapse
|
18
|
von Caemmerer S, Ghannoum O, Furbank RT. C4 photosynthesis: 50 years of discovery and innovation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:97-102. [PMID: 28110274 PMCID: PMC5444450 DOI: 10.1093/jxb/erw491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
It is now over half a century since the biochemical characterization of the C4 photosynthetic pathway, and this special issue highlights the sheer breadth of current knowledge. New genomic and transcriptomic information shows that multi-level regulation of gene expression is required for the pathway to function, yet we know it to be one of the most dynamic examples of convergent evolution. Now, a focus on the molecular transition from C3-C4 intermediates, together with improved mathematical models, experimental tools and transformation systems, holds great promise for improving C4 photosynthesis in crops.
Collapse
Affiliation(s)
- Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW 2753, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| |
Collapse
|