1
|
Zhou Y, Gunn LH, Birch R, Andersson I, Whitney SM. Grafting Rhodobacter sphaeroides with red algae Rubisco to accelerate catalysis and plant growth. NATURE PLANTS 2023; 9:978-986. [PMID: 37291398 DOI: 10.1038/s41477-023-01436-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 05/10/2023] [Indexed: 06/10/2023]
Abstract
Improving the carboxylation properties of Rubisco has primarily arisen from unforeseen amino acid substitutions remote from the catalytic site. The unpredictability has frustrated rational design efforts to enhance plant Rubisco towards the prized growth-enhancing carboxylation properties of red algae Griffithsia monilis GmRubisco. To address this, we determined the crystal structure of GmRubisco to 1.7 Å. Three structurally divergent domains were identified relative to the red-type bacterial Rhodobacter sphaeroides RsRubisco that, unlike GmRubisco, are expressed in Escherichia coli and plants. Kinetic comparison of 11 RsRubisco chimaeras revealed that incorporating C329A and A332V substitutions from GmRubisco Loop 6 (corresponding to plant residues 328 and 331) into RsRubisco increased the carboxylation rate (kcatc) by 60%, the carboxylation efficiency in air by 22% and the CO2/O2 specificity (Sc/o) by 7%. Plastome transformation of this RsRubisco Loop 6 mutant into tobacco enhanced photosynthesis and growth up to twofold over tobacco producing wild-type RsRubisco. Our findings demonstrate the utility of RsRubisco for the identification and in planta testing of amino acid grafts from algal Rubisco that can enhance the enzyme's carboxylase potential.
Collapse
Affiliation(s)
- Yu Zhou
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Laura H Gunn
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Rosemary Birch
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Inger Andersson
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- Norwegian College of Fisheries Sciences, UiT Arctic University of Norway, Tromsø, Norway
- Institute of Biotechnology, Academy of Sciences of the Czech Republic, Biocev, Vestec, Czech Republic
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.
| |
Collapse
|
2
|
Oh ZG, Askey B, Gunn LH. Red Rubiscos and opportunities for engineering green plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:520-542. [PMID: 36055563 PMCID: PMC9833100 DOI: 10.1093/jxb/erac349] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Nature's vital, but notoriously inefficient, CO2-fixing enzyme Rubisco often limits the growth of photosynthetic organisms including crop species. Form I Rubiscos comprise eight catalytic large subunits and eight auxiliary small subunits and can be classified into two distinct lineages-'red' and 'green'. While red-type Rubiscos (Form IC and ID) are found in rhodophytes, their secondary symbionts, and certain proteobacteria, green-type Rubiscos (Form IA and IB) exist in terrestrial plants, chlorophytes, cyanobacteria, and other proteobacteria. Eukaryotic red-type Rubiscos exhibit desirable kinetic properties, namely high specificity and high catalytic efficiency, with certain isoforms outperforming green-type Rubiscos. However, it is not yet possible to functionally express a high-performing red-type Rubisco in chloroplasts to boost photosynthetic carbon assimilation in green plants. Understanding the molecular and evolutionary basis for divergence between red- and green-type Rubiscos could help us to harness the superior CO2-fixing power of red-type Rubiscos. Here we review our current understanding about red-type Rubisco distribution, biogenesis, and sequence-structure, and present opportunities and challenges for utilizing red-type Rubisco kinetics towards crop improvements.
Collapse
Affiliation(s)
- Zhen Guo Oh
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Bryce Askey
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | | |
Collapse
|
3
|
Zhang J, Liu G, Carvajal AI, Wilson RH, Cai Z, Li Y. Discovery of a readily heterologously expressed Rubisco from the deep sea with potential for CO 2 capture. BIORESOUR BIOPROCESS 2021; 8:86. [PMID: 38650243 PMCID: PMC10992382 DOI: 10.1186/s40643-021-00439-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/27/2021] [Indexed: 11/10/2022] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key CO2-fixing enzyme in photosynthesis, is notorious for its low carboxylation. We report a highly active and assembly-competent Form II Rubisco from the endosymbiont of a deep-sea tubeworm Riftia pachyptila (RPE Rubisco), which shows a 50.5% higher carboxylation efficiency than that of a high functioning Rubisco from Synechococcus sp. PCC7002 (7002 Rubisco). It is a simpler hexamer with three pairs of large subunit homodimers around a central threefold symmetry axis. Compared with 7002 Rubisco, it showed a 3.6-fold higher carbon capture efficiency in vivo using a designed CO2 capture model. The simple structure, high carboxylation efficiency, easy heterologous soluble expression/assembly make RPE Rubisco a ready-to-deploy enzyme for CO2 capture that does not require complex co-expression of chaperones. The chemosynthetic CO2 fixation machinery of chemolithoautotrophs, CO2-fixing endosymbionts, may be more efficient than previously realized with great potential for next-generation microbial CO2 sequestration platforms.
Collapse
Affiliation(s)
- Junli Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Guoxia Liu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Alonso I Carvajal
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Robert H Wilson
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany.
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Zhen Cai
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| |
Collapse
|
4
|
Cummins PL. The Coevolution of RuBisCO, Photorespiration, and Carbon Concentrating Mechanisms in Higher Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:662425. [PMID: 34539685 PMCID: PMC8440988 DOI: 10.3389/fpls.2021.662425] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/26/2021] [Indexed: 05/20/2023]
Abstract
Ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (RuBisCO) is the carbon-fixing enzyme present in most photosynthetic organisms, converting CO2 into organic matter. Globally, photosynthetic efficiency in terrestrial plants has become increasingly challenged in recent decades due to a rapid increase in atmospheric CO2 and associated changes toward warmer and dryer environments. Well adapted for these new climatic conditions, the C4 photosynthetic pathway utilizes carbon concentrating mechanisms to increase CO2 concentrations surrounding RuBisCO, suppressing photorespiration from the oxygenase catalyzed reaction with O2. The energy efficiency of C3 photosynthesis, from which the C4 pathway evolved, is thought to rely critically on an uninterrupted supply of chloroplast CO2. Part of the homeostatic mechanism that maintains this constancy of supply involves the CO2 produced as a byproduct of photorespiration in a negative feedback loop. Analyzing the database of RuBisCO kinetic parameters, we suggest that in genera (Flaveria and Panicum) for which both C3 and C4 examples are available, the C4 pathway evolved only from C3 ancestors possessing much lower than the average carboxylase specificity relative to that of the oxygenase reaction (S C/O=S C/S O), and hence, the higher CO2 levels required for development of the photorespiratory CO2 pump (C2 photosynthesis) essential in the initial stages of C4 evolution, while in the later stage (final optimization phase in the Flaveria model) increased CO2 turnover may have occurred, which would have been supported by the higher CO2 levels. Otherwise, C4 RuBisCO kinetic traits remain little changed from the ancestral C3 species. At the opposite end of the spectrum, C3 plants (from Limonium) with higher than average S C/O, which may be associated with the ability of increased CO2, relative to O2, affinity to offset reduced photorespiration and chloroplast CO2 levels, can tolerate high stress environments. It is suggested that, instead of inherently constrained by its kinetic mechanism, RuBisCO possesses the extensive kinetic plasticity necessary for adaptation to changes in photorespiration that occur in the homeostatic regulation of CO2 supply under a broad range of abiotic environmental conditions.
Collapse
|
5
|
Gunn LH, Martin Avila E, Birch R, Whitney SM. The dependency of red Rubisco on its cognate activase for enhancing plant photosynthesis and growth. Proc Natl Acad Sci U S A 2020; 117:25890-25896. [PMID: 32989135 PMCID: PMC7568259 DOI: 10.1073/pnas.2011641117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Plant photosynthesis and growth are often limited by the activity of the CO2-fixing enzyme Rubisco. The broad kinetic diversity of Rubisco in nature is accompanied by differences in the composition and compatibility of the ancillary proteins needed for its folding, assembly, and metabolic regulation. Variations in the protein folding needs of catalytically efficient red algae Rubisco prevent their production in plants. Here, we show this impediment does not extend to Rubisco from Rhodobacter sphaeroides (RsRubisco)-a red-type Rubisco able to assemble in plant chloroplasts. In transplastomic tobRsLS lines expressing a codon optimized Rs-rbcLS operon, the messenger RNA (mRNA) abundance was ∼25% of rbcL transcript and RsRubisco ∼40% the Rubisco content in WT tobacco. To mitigate the low activation status of RsRubisco in tobRsLS (∼23% sites active under ambient CO2), the metabolic repair protein RsRca (Rs-activase) was introduced via nuclear transformation. RsRca production in the tobRsLS::X progeny matched endogenous tobacco Rca levels (∼1 µmol protomer·m2) and enhanced RsRubisco activation to 75% under elevated CO2 (1%, vol/vol) growth. Accordingly, the rate of photosynthesis and growth in the tobRsLS::X lines were improved >twofold relative to tobRsLS. Other tobacco lines producing RsRubisco containing alternate diatom and red algae S-subunits were nonviable as CO2-fixation rates (kcatc) were reduced >95% and CO2/O2 specificity impaired 30-50%. We show differences in hybrid and WT RsRubisco biogenesis in tobacco correlated with assembly in Escherichia coli advocating use of this bacterium to preevaluate the kinetic and chloroplast compatibility of engineered RsRubisco, an isoform amenable to directed evolution.
Collapse
Affiliation(s)
- Laura H Gunn
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Elena Martin Avila
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Rosemary Birch
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| |
Collapse
|
6
|
Cummins PL, Kannappan B, Gready JE. Response: Commentary: Directions for Optimization of Photosynthetic Carbon Fixation: RuBisCO's Efficiency May Not Be So Constrained After All. FRONTIERS IN PLANT SCIENCE 2019; 10:1426. [PMID: 31824523 PMCID: PMC6884029 DOI: 10.3389/fpls.2019.01426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 10/15/2019] [Indexed: 05/29/2023]
|
7
|
Galmés J, Capó-Bauçà S, Niinemets Ü, Iñiguez C. Potential improvement of photosynthetic CO 2 assimilation in crops by exploiting the natural variation in the temperature response of Rubisco catalytic traits. CURRENT OPINION IN PLANT BIOLOGY 2019; 49:60-67. [PMID: 31234057 DOI: 10.1016/j.pbi.2019.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/25/2019] [Accepted: 05/02/2019] [Indexed: 05/25/2023]
Abstract
The enhancement of the photosynthetic capacity of crops by the expression of more efficient Rubisco versions has been a main target in the field of plant photosynthesis improvement. However, such an increase in the photosynthetic efficiency will depend on the environmental conditions and on the responsiveness of Rubisco to temperature and CO2 availability. After an exhaustive compilation and standardization of the data published so far, a large natural variability in the thermal responses of Rubisco kinetic parameters in higher plant species was revealed. The variability observed was related to the photosynthetic type but a limited adaptation to the species thermal environment was found. We provide theoretical evidence that the existence of distinctive Rubisco responses to varying temperature and CO2 concentration constitutes a promising avenue for increasing the photosynthetic capacity of important crops under future climatic conditions.
Collapse
Affiliation(s)
- Jeroni Galmés
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain.
| | - Sebastià Capó-Bauçà
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
| | - Ülo Niinemets
- Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006 Tartu, Estonia; Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
| | - Concepción Iñiguez
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
| |
Collapse
|
8
|
Artier J, Holland SC, Miller NT, Zhang M, Burnap RL. Synthetic DNA system for structure-function studies of the high affinity CO2 uptake NDH-13 protein complex in cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1108-1118. [DOI: 10.1016/j.bbabio.2018.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 11/26/2022]
|
9
|
Cummins PL, Kannappan B, Gready JE. Revised mechanism of carboxylation of ribulose-1,5-biphosphate by rubisco from large scale quantum chemical calculations. J Comput Chem 2018; 39:1656-1665. [PMID: 29756365 DOI: 10.1002/jcc.25343] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 01/06/2023]
Abstract
Here, we describe a computational approach for studying enzymes that catalyze complex multi-step reactions and apply it to Ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco), the enzyme that fixes atmospheric carbon dioxide within photosynthesis. In the 5-step carboxylase reaction, the substrate Ribulose-1,5-bisphosphate (RuBP) first binds Rubisco and undergoes enolization before binding the second substrate, CO2 . Hydration of the RuBP.CO2 complex is followed by CC bond scission and stereospecific protonation. However, details of the roles and protonation states of active-site residues, and sources of protons and water, remain highly speculative. Large-scale computations on active-site models provide a means to better understand this complex chemical mechanism. The computational protocol comprises a combination of hybrid semi-empirical quantum mechanics and molecular mechanics within constrained molecular dynamics simulations, together with constrained gradient minimization calculations using density functional theory. Alternative pathways for hydration of the RuBP.CO2 complex and associated active-site protonation networks and proton and water sources were investigated. The main findings from analysis of the resulting energetics advocate major revision to existing mechanisms such that: hydration takes place anti to the CO2 ; both hydration and CC bond scission require early protonation of CO2 in the RuBP.CO2 complex; CC bond scission and stereospecific protonation reactions are concerted and, effectively, there is only one stable intermediate, the C3-gemdiolate complex. Our main conclusions for interpreting enzyme kinetic results are that the gemdiolate may represent the elusive Michaelis-Menten-like complex corresponding to the empirical Km (=Kc ) with turnover to product via bond scission concerted with stereospecific protonation consistent with the observed catalytic rate. © 2018 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Peter L Cummins
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Babu Kannappan
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Jill E Gready
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| |
Collapse
|
10
|
Liu D, Ramya RCS, Mueller-Cajar O. Surveying the expanding prokaryotic Rubisco multiverse. FEMS Microbiol Lett 2018; 364:3983162. [PMID: 28854711 DOI: 10.1093/femsle/fnx156] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 07/19/2017] [Indexed: 11/12/2022] Open
Abstract
The universal, but catalytically modest, CO2-fixing enzyme Rubisco is currently experiencing intense interest by researchers aiming to enhance crop photosynthesis. These efforts are mostly focused on the highly conserved hexadecameric enzyme found in land plants. In comparison, prokaryotic organisms harbor a far greater diversity in Rubisco forms. Recent work towards improving our appreciation of microbial Rubisco properties and harnessing their potential is surveyed. New structural models are providing informative glimpses into catalytic subtleties and diverse oligomeric states. Ongoing characterization is informing us about the conservation of constraints, such as sugar phosphate inhibition and the associated dependence on Rubisco activase helper proteins. Prokaryotic Rubiscos operate under a far wider range of metabolic contexts than the photosynthetic function of higher plant enzymes. Relaxed selection pressures may have resulted in the exploration of a larger volume of sequence space than permitted in organisms performing oxygenic photosynthesis. To tap into the potential of microbial Rubiscos, in vivo selection systems are being used to discover functional metagenomic Rubiscos. Various directed evolution systems to optimize their function have been developed. It is anticipated that this approach will provide access to biotechnologically valuable enzymes that cannot be encountered in the higher plant Rubisco space.
Collapse
Affiliation(s)
- Di Liu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | | | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| |
Collapse
|
11
|
Cummins PL, Kannappan B, Gready JE. Directions for Optimization of Photosynthetic Carbon Fixation: RuBisCO's Efficiency May Not Be So Constrained After All. FRONTIERS IN PLANT SCIENCE 2018; 9:183. [PMID: 29545812 PMCID: PMC5838012 DOI: 10.3389/fpls.2018.00183] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/31/2018] [Indexed: 05/19/2023]
Abstract
The ubiquitous enzyme Ribulose 1,5-bisphosphate carboxylase-oxygenase (RuBisCO) fixes atmospheric carbon dioxide within the Calvin-Benson cycle that is utilized by most photosynthetic organisms. Despite this central role, RuBisCO's efficiency surprisingly struggles, with both a very slow turnover rate to products and also impaired substrate specificity, features that have long been an enigma as it would be assumed that its efficiency was under strong evolutionary pressure. RuBisCO's substrate specificity is compromised as it catalyzes a side-fixation reaction with atmospheric oxygen; empirical kinetic results show a trend to tradeoff between relative specificity and low catalytic turnover rate. Although the dominant hypothesis has been that the active-site chemistry constrains the enzyme's evolution, a more recent study on RuBisCO stability and adaptability has implicated competing selection pressures. Elucidating these constraints is crucial for directing future research on improving photosynthesis, as the current literature casts doubt on the potential effectiveness of site-directed mutagenesis to improve RuBisCO's efficiency. Here we use regression analysis to quantify the relationships between kinetic parameters obtained from empirical data sets spanning a wide evolutionary range of RuBisCOs. Most significantly we found that the rate constant for dissociation of CO2 from the enzyme complex was much higher than previous estimates and comparable with the corresponding catalytic rate constant. Observed trends between relative specificity and turnover rate can be expressed as the product of negative and positive correlation factors. This provides an explanation in simple kinetic terms of both the natural variation of relative specificity as well as that obtained by reported site-directed mutagenesis results. We demonstrate that the kinetic behaviour shows a lesser rather than more constrained RuBisCO, consistent with growing empirical evidence of higher variability in relative specificity. In summary our analysis supports an explanation for the origin of the tradeoff between specificity and turnover as due to competition between protein stability and activity, rather than constraints between rate constants imposed by the underlying chemistry. Our analysis suggests that simultaneous improvement in both specificity and turnover rate of RuBisCO is possible.
Collapse
|
12
|
Orr DJ, Pereira AM, da Fonseca Pereira P, Pereira-Lima ÍA, Zsögön A, Araújo WL. Engineering photosynthesis: progress and perspectives. F1000Res 2017; 6:1891. [PMID: 29263782 PMCID: PMC5658708 DOI: 10.12688/f1000research.12181.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/27/2017] [Indexed: 12/11/2022] Open
Abstract
Photosynthesis is the basis of primary productivity on the planet. Crop breeding has sustained steady improvements in yield to keep pace with population growth increases. Yet these advances have not resulted from improving the photosynthetic process
per se but rather of altering the way carbon is partitioned within the plant. Mounting evidence suggests that the rate at which crop yields can be boosted by traditional plant breeding approaches is wavering, and they may reach a “yield ceiling” in the foreseeable future. Further increases in yield will likely depend on the targeted manipulation of plant metabolism. Improving photosynthesis poses one such route, with simulations indicating it could have a significant transformative influence on enhancing crop productivity. Here, we summarize recent advances of alternative approaches for the manipulation and enhancement of photosynthesis and their possible application for crop improvement.
Collapse
Affiliation(s)
- Douglas J Orr
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Auderlan M Pereira
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Paula da Fonseca Pereira
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Ítalo A Pereira-Lima
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Agustin Zsögön
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Wagner L Araújo
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| |
Collapse
|
13
|
Heureux AMC, Young JN, Whitney SM, Eason-Hubbard MR, Lee RBY, Sharwood RE, Rickaby REM. The role of Rubisco kinetics and pyrenoid morphology in shaping the CCM of haptophyte microalgae. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3959-3969. [PMID: 28582571 PMCID: PMC5853415 DOI: 10.1093/jxb/erx179] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/15/2017] [Indexed: 05/18/2023]
Abstract
The haptophyte algae are a cosmopolitan group of primary producers that contribute significantly to the marine carbon cycle and play a major role in paleo-climate studies. Despite their global importance, little is known about carbon assimilation in haptophytes, in particular the kinetics of their Form 1D CO2-fixing enzyme, Rubisco. Here we examine Rubisco properties of three haptophytes with a range of pyrenoid morphologies (Pleurochrysis carterae, Tisochrysis lutea, and Pavlova lutheri) and the diatom Phaeodactylum tricornutum that exhibit contrasting sensitivities to the trade-offs between substrate affinity (Km) and turnover rate (kcat) for both CO2 and O2. The pyrenoid-containing T. lutea and P. carterae showed lower Rubisco content and carboxylation properties (KC and kCcat) comparable with those of Form 1D-containing non-green algae. In contrast, the pyrenoid-lacking P. lutheri produced Rubisco in 3-fold higher amounts, and displayed a Form 1B Rubisco kCcat-KC relationship and increased CO2/O2 specificity that, when modeled in the context of a C3 leaf, supported equivalent rates of photosynthesis to higher plant Rubisco. Correlation between the differing Rubisco properties and the occurrence and localization of pyrenoids with differing intracellular CO2:O2 microenvironments has probably influenced the divergent evolution of Form 1B and 1D Rubisco kinetics.
Collapse
Affiliation(s)
- Ana M C Heureux
- University of Oxford, Department of Earth Sciences, South Parks Road, Oxford, UK
| | - Jodi N Young
- University of Washington, School of Oceanography, Seattle, WA, USA
| | - Spencer M Whitney
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra ACT, Australia
| | | | - Renee B Y Lee
- University of Oxford, Department of Earth Sciences, South Parks Road, Oxford, UK
- University of Reading, School of Biological Sciences, Reading, Berkshire, UK
| | - Robert E Sharwood
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Rosalind E M Rickaby
- University of Oxford, Department of Earth Sciences, South Parks Road, Oxford, UK
| |
Collapse
|
14
|
Mueller-Cajar O. The Diverse AAA+ Machines that Repair Inhibited Rubisco Active Sites. Front Mol Biosci 2017; 4:31. [PMID: 28580359 PMCID: PMC5437159 DOI: 10.3389/fmolb.2017.00031] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/29/2017] [Indexed: 11/13/2022] Open
Abstract
Gaseous carbon dioxide enters the biosphere almost exclusively via the active site of the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). This highly conserved catalyst has an almost universal propensity to non-productively interact with its substrate ribulose 1,5-bisphosphate, leading to the formation of dead-end inhibited complexes. In diverse autotrophic organisms this tendency has been counteracted by the recruitment of dedicated AAA+ (ATPases associated with various cellular activities) proteins that all use the energy of ATP hydrolysis to remodel inhibited Rubisco active sites leading to release of the inhibitor. Three evolutionarily distinct classes of these Rubisco activases (Rcas) have been discovered so far. Green and red-type Rca are mostly found in photosynthetic eukaryotes of the green and red plastid lineage respectively, whereas CbbQO is associated with chemoautotrophic bacteria. Ongoing mechanistic studies are elucidating how the various motors are utilizing both similar and contrasting strategies to ultimately perform their common function of cracking the inhibited Rubisco active site. The best studied mechanism utilized by red-type Rca appears to involve transient threading of the Rubisco large subunit C-terminal peptide, reminiscent of the action performed by Clp proteases. As well as providing a fascinating example of convergent molecular evolution, Rca proteins can be considered promising crop-improvement targets. Approaches aiming to replace Rubisco in plants with improved enzymes will need to ensure the presence of a compatible Rca protein. The thermolability of the Rca protein found in crop plants provides an opportunity to fortify photosynthesis against high temperature stress. Photosynthesis also appears to be limited by Rca when light conditions are fluctuating. Synthetic biology strategies aiming to enhance the autotrophic CO2 fixation machinery will need to take into consideration the requirement for Rubisco activases as well as their properties.
Collapse
Affiliation(s)
- Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological UniversitySingapore, Singapore
| |
Collapse
|
15
|
Raines C, Traynor M, Ingram J. Experimental botany in 2017. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:347-349. [PMID: 28201652 PMCID: PMC5444439 DOI: 10.1093/jxb/erw504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Christine Raines
- Editor in Chief, Journal of Experimental BotanyDepartment of Biological Sciences, University of Essex, Colchester, UK
| | - Mary Traynor
- Executive Editor, Journal of Experimental BotanyBailrigg House, Lancaster University, Lancaster, UK
| | - Jonathan Ingram
- Senior Commissioning Editor/ Science Writer, Journal of Experimental BotanyBailrigg House, Lancaster University, Lancaster, UK
| |
Collapse
|