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Eshenour K, Hotto A, Michel EJS, Oh ZG, Stern DB. Transgenic expression of Rubisco accumulation factor2 and Rubisco subunits increases photosynthesis and growth in maize. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4024-4037. [PMID: 38696303 DOI: 10.1093/jxb/erae186] [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: 11/01/2023] [Accepted: 05/01/2024] [Indexed: 05/04/2024]
Abstract
Carbon assimilation by Rubisco is often a limitation to photosynthesis and therefore plant productivity. We have previously shown that transgenic co-expression of the Rubisco large (LS) and small (SS) subunits along with an essential Rubisco accumulation factor, Raf1, leads to faster growth, increased photosynthesis, and enhanced chilling tolerance in maize (Zea mays). Maize also requires Rubisco accumulation factor2 (Raf2) for full accumulation of Rubisco. Here we have analyzed transgenic maize lines with increased expression of Raf2 or Raf2 plus LS and SS. We show that increasing Raf2 expression alone had minor effects on photosynthesis, whereas expressing Raf2 with Rubisco subunits led to increased Rubisco content, more rapid carbon assimilation, and greater plant height, most notably in plants at least 6 weeks of age. The magnitude of the effects was similar to what was observed previously for expression of Raf1 together with Rubisco subunits. Taken together, this suggests that increasing the amount of either assembly factor with Rubisco subunits can independently enhance Rubisco abundance and some aspects of plant performance. These results could also imply either synergy or a degree of functional redundancy for Raf1 and Raf2, the latter of whose precise role in Rubisco assembly is currently unknown.
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Affiliation(s)
| | - Amber Hotto
- Boyce Thompson Institute, 533 Tower Rd, Ithaca, NY 14853, USA
| | | | - Zhen Guo Oh
- Boyce Thompson Institute, 533 Tower Rd, Ithaca, NY 14853, USA
- Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - David B Stern
- Boyce Thompson Institute, 533 Tower Rd, Ithaca, NY 14853, USA
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2
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Liu Z, Cheng J. C 4 rice engineering, beyond installing a C 4 cycle. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108256. [PMID: 38091938 DOI: 10.1016/j.plaphy.2023.108256] [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: 04/06/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 02/15/2024]
Abstract
C4 photosynthesis in higher plants is carried out by two distinct cell types: mesophyll cells and bundle sheath cells, as a result highly concentrated carbon dioxide is released surrounding RuBisCo in chloroplasts of bundle sheath cells and the photosynthetic efficiency is significantly higher than that of C3 plants. The evolution of the dual-cell C4 cycle involved complex modifications to leaf anatomy and cell ultra-structures. These include an increase in leaf venation, the formation of Kranz anatomy, changes in chloroplast morphology in bundle sheath cells, and increases in the density of plasmodesmata at interfaces between the bundle sheath and mesophyll cells. It is predicted that cereals will be in severe worldwide shortage at the mid-term of this century. Rice is a staple food that feeds more than half of the world's population. If rice can be engineered to perform C4 photosynthesis, it is estimated that rice yield will be increased by at least 50% due to enhanced photosynthesis. Thus, the Second Green Revolution has been launched on this principle by genetically installing C4 photosynthesis into C3 crops. The studies on molecular mechanisms underlying the changes in leaf morphoanatomy involved in C4 photosynthesis have made great progress in recent years. As there are plenty of reviews discussing the installment of the C4 cycle, we focus on the current progress and challenges posed to the research regarding leaf anatomy and cell ultra-structure modifications made towards the development of C4 rice.
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Affiliation(s)
- Zheng Liu
- State Key Laboratory of North China Crop Improvement and Regulation, College of Agronomy, Hebei Agricultural University, Baoding, 071001, China.
| | - Jinjin Cheng
- College of Agronomy, Shanxi Agricultural University, Jinzhong, 030801, China
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3
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Wang R, Song H, Zhang W, Wang N, Zhang S, Shao R, Liu C. Structural insights into the functions of Raf1 and Bsd2 in hexadecameric Rubisco assembly. MOLECULAR PLANT 2023; 16:1927-1936. [PMID: 37853692 DOI: 10.1016/j.molp.2023.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 09/20/2023] [Accepted: 10/17/2023] [Indexed: 10/20/2023]
Abstract
Hexadecameric form I Rubisco, which consisting consists of eight large (RbcL) and eight small (RbcS) subunits, is the most abundant enzyme on earth. Extensive efforts to engineer an improved Rubisco to speed up its catalytic efficiency and ultimately increase agricultural productivity. However, difficulties with correct folding and assembly in foreign hosts or in vitro have hampered the genetic manipulation of hexadecameric Rubisco. In this study, we reconstituted Synechococcus sp. PCC6301 Rubisco in vitro using the chaperonin system and assembly factors from cyanobacteria and Arabidopsis thaliana (At). Rubisco holoenzyme was produced in the presence of cyanobacterial Rubisco accumulation factor 1 (Raf1) alone or both AtRaf1 and bundle-sheath defective-2 (AtBsd2) from Arabidopsis. RbcL released from GroEL is assembly capable in the presence of ATP, and AtBsd2 functions downstream of AtRaf1. Cryo-EM structures of RbcL8-AtRaf18, RbcL8-AtRaf14-AtBsd28, and RbcL8 revealed that the interactions between RbcL and AtRaf1 are looser than those between prokaryotic RbcL and Raf1, with AtRaf1 tilting 7° farther away from RbcL. AtBsd2 stabilizes the flexible regions of RbcL, including the N and C termini, the 60s loop, and loop 6. Using these data, combined with previous findings, we propose the possible biogenesis pathways of prokaryotic and eukaryotic Rubisco.
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Affiliation(s)
- Ran Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Hui Song
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Wenjuan Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Ning Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Shijia Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Ruiqi Shao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Cuimin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China.
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Jin K, Chen G, Yang Y, Zhang Z, Lu T. Strategies for manipulating Rubisco and creating photorespiratory bypass to boost C 3 photosynthesis: Prospects on modern crop improvement. PLANT, CELL & ENVIRONMENT 2023; 46:363-378. [PMID: 36444099 DOI: 10.1111/pce.14500] [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: 09/15/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 06/16/2023]
Abstract
Photosynthesis is a process that uses solar energy to fix CO2 in the air and converts it into sugar, and ultimately powers almost all life activities on the earth. C3 photosynthesis is the most common form of photosynthesis in crops. Current efforts of increasing crop yields in response to growing global food requirement are mostly focused on improving C3 photosynthesis. In this review, we summarized the strategies of C3 photosynthesis improvement in terms of Rubisco properties and photorespiratory limitation. Potential engineered targets include Rubisco subunits and their catalytic sites, Rubisco assembly chaperones, and Rubisco activase. In addition, we reviewed multiple photorespiratory bypasses built by strategies of synthetic biology to reduce the release of CO2 and ammonia and minimize energy consumption by photorespiration. The potential strategies are suggested to enhance C3 photosynthesis and boost crop production.
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Affiliation(s)
- Kaining Jin
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
- Department of Plant Sciences, Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - Guoxin Chen
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Yirong Yang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Zhiguo Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Tiegang Lu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
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Buck S, Rhodes T, Gionfriddo M, Skinner T, Yuan D, Birch R, Kapralov MV, Whitney SM. Escherichia coli expressing chloroplast chaperones as a proxy to test heterologous Rubisco production in leaves. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:664-676. [PMID: 36322613 DOI: 10.1093/jxb/erac435] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Rubisco is a fundamental enzyme in photosynthesis and therefore for life. Efforts to improve plant Rubisco performance have been hindered by the enzymes' complex chloroplast biogenesis requirements. New Synbio approaches, however, now allow the production of some plant Rubisco isoforms in Escherichia coli. While this enhances opportunities for catalytic improvement, there remain limitations in the utility of the expression system. Here we generate, optimize, and test a robust Golden Gate cloning E. coli expression system incorporating the protein folding machinery of tobacco chloroplasts. By comparing the expression of different plant Rubiscos in both E. coli and plastome-transformed tobacco, we show that the E. coli expression system can accurately predict high level Rubisco production in chloroplasts but poorly forecasts the biogenesis potential of isoforms with impaired production in planta. We reveal that heterologous Rubisco production in E. coli and tobacco plastids poorly correlates with Rubisco large subunit phylogeny. Our findings highlight the need to fully understand the factors governing Rubisco biogenesis if we are to deliver an efficient, low-cost screening tool that can accurately emulate chloroplast expression.
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Affiliation(s)
- Sally Buck
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Tim Rhodes
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Matteo Gionfriddo
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Tanya Skinner
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Ding Yuan
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Rosemary Birch
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Maxim V Kapralov
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Spencer M Whitney
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
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6
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Oogo Y, Takemura M, Sakamoto A, Misawa N, Shimada H. Orange protein, phytoene synthase regulator, has protein disulfide reductase activity. PLANT SIGNALING & BEHAVIOR 2022; 17:2072094. [PMID: 35699140 PMCID: PMC9225386 DOI: 10.1080/15592324.2022.2072094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Orange protein (OR) is known to interact with phytoene synthase (PSY) that commits the first step in carotenoid biosynthesis, and functions as a major post-transcriptional regulator on PSY. We here tried to reveal enzymatic characteristics of OR, that is, protein disulfide reductase (PDR) activity of the Arabidopsis thaliana OR protein (AtOR) was analyzed using dieosin glutathione disulfide (Di-E-GSSG) as a substrate. The AtOR part containing only the zinc (Zn)-finger motif was found to show PDR activity, with an apparent Km of 12,632 nM, Kcat of 11.85 min-1, and KcatKm-1 of 15.6 × 103 M-1sec-1. To evaluate the significance of the N-terminal region of AtOR, we examined the kinetic parameters of a fusion protein composed of the N-terminal region and the Zn-finger motif from AtOR. Consequently, the fusion protein had lower values for Km (2,074 nM) and Kcat (3.18 min-1) and higher catalytic efficiency (25.9 × 103 M-1sec-1) than that of only the Zn-finger motif part, suggesting that the N-terminal region of AtOR should be important for substrate affinity and catalytic efficiency of PDR activity. Complementation experiments with E. coli further demonstrated that AtOR containing the N-terminal region and the Zn-finger motif increases phytoene synthase activity of AtPSY especially under reduced circumstances retaining a NADPH- and H+-regeneration system.
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Affiliation(s)
- Yuto Oogo
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Miho Takemura
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi-shi, Japan
| | - Atsushi Sakamoto
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Norihiko Misawa
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi-shi, Japan
| | - Hiroshi Shimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
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Pradhan B, Panda D, Bishi SK, Chakraborty K, Muthusamy SK, Lenka SK. Progress and prospects of C 4 trait engineering in plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:920-931. [PMID: 35727191 DOI: 10.1111/plb.13446] [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: 01/14/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Incorporating C4 photosynthetic traits into C3 crops is a rational approach for sustaining future demands for crop productivity. Using classical plant breeding, engineering this complex trait is unlikely to achieve its target. Therefore, it is critical and timely to implement novel biotechnological crop improvement strategies to accomplish this goal. However, a fundamental understanding of C3 , C4 , and C3 -C4 intermediate metabolism is crucial for the targeted use of biotechnological tools. This review assesses recent progress towards engineering C4 photosynthetic traits in C3 crops. We also discuss lessons learned from successes and failures of recent genetic engineering attempts in C3 crops, highlighting the pros and cons of using rice as a model plant for short-, medium- and long-term goals of genetic engineering. This review provides an integrated approach towards engineering improved photosynthetic efficiency in C3 crops for sustaining food, fibre and fuel production around the globe.
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Affiliation(s)
- B Pradhan
- Department of Agricultural Biotechnology, Faculty Centre for Integrated Rural Development and Management, Ramakrishna Mission Vivekananda Educational and Research Institute, Kolkata, India
| | - D Panda
- Department of Biodiversity & Conservation of Natural Resources, Central University of Odisha, Koraput, India
| | - S K Bishi
- School of Genomics and Molecular Breeding, ICAR-Indian Institute of Agricultural Biotechnology, Ranchi, India
| | - K Chakraborty
- Department of Plant Physiology, ICAR-National Rice Research Institute, Cuttack, India
| | - S K Muthusamy
- Division of Crop Improvement, ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, India
| | - S K Lenka
- Department of Plant Biotechnology, Gujarat Biotechnology University, Gujarat, India
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Structural insights into cyanobacterial RuBisCO assembly coordinated by two chaperones Raf1 and RbcX. Cell Discov 2022; 8:93. [PMID: 36123352 PMCID: PMC9485235 DOI: 10.1038/s41421-022-00436-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 06/13/2022] [Indexed: 11/18/2022] Open
Abstract
RuBisCO is the most abundant enzyme in nature, catalyzing the fixation of CO2 in photosynthesis. Its common form consists of eight RbcL and eight RbcS subunits, the assembly of which requires a series of chaperones that include RbcX and RuBisCO accumulation factor 1 (Raf1). To understand how these RuBisCO-specific chaperones function during cyanobacterial RbcL8RbcS8 (L8S8) holoenzyme formation, we solved a 3.3-Å cryo-electron microscopy structure of a 32-subunit RbcL8Raf18RbcX16 (L8F8X16) assembly intermediate from Anabaena sp. PCC 7120. Comparison to the previously resolved L8F8 and L8X16 structures together with biochemical assays revealed that the L8F8X16 complex forms a rather dynamic structural intermediate, favoring RbcS displacement of Raf1 and RbcX. In vitro assays further demonstrated that both Raf1 and RbcX function to regulate RuBisCO condensate formation by restricting CcmM35 binding to the stably assembled L8S8 holoenzymes. Combined with previous findings, we propose a model on how Raf1 and RbcX work in concert to facilitate, and regulate, cyanobacterial RuBisCO assembly as well as disassembly of RuBisCO condensates.
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Li H, Li L, Wu W, Wang F, Zhou F, Lin Y. SvSTL1 in the large subunit family of ribonucleotide reductases plays a major role in chloroplast development of Setaria viridis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:625-641. [PMID: 35608125 DOI: 10.1111/tpj.15842] [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: 11/03/2021] [Revised: 05/04/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Ribonucleotide reductases (RNRs) are essential enzymes in DNA synthesis. However, little is known about the RNRs in plants. Here, we identified a svstl1 mutant from the self-created ethyl methanesulfonate (EMS) mutant library of Setaria viridis. The mutant leaves exhibited a bleaching phenotype at the heading stage. Paraffin section analysis showed the destruction of the C4 Kranz anatomy. Transmission electron microscopy results further demonstrated the severely disturbed development of some chloroplasts. MutMap analysis revealed that the SvSTL1 gene is the primary candidate, encoding a large subunit of RNRs. Complementation experiments confirmed that SvSTL1 is responsible for the phenotype of svstl1. There are two additional RNR large subunit homologs in S. viridis, SvSTL2 and SvSTL3. To further understand the functions of these three RNR large subunit genes, a series of mutants were generated via CRISPR/Cas9 technology. In striking contrast to the finding that all three SvSTLs interact with the RNR small subunit, the phenotype varied along with the copies of chloroplast genome among different svstl single mutants: the svstl1 mutant exhibited pronounced chloroplast development and significantly fewer copies of the chloroplast genome than the svstl2 or svstl3 single mutants. These results suggested that SvSTL1 plays a major role in the optimal function of RNRs and is essential for chloroplast development. Furthermore, through the analysis of double and triple mutants, the study provides new insights into the finely tuned coordination among SvSTLs to maintain normal chloroplast development in the emerging C4 model plant S. viridis.
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Affiliation(s)
- Huanying Li
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Lin Li
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Weichen Wu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Fei Wang
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Fei Zhou
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
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Lin MT, Salihovic H, Clark FK, Hanson MR. Improving the efficiency of Rubisco by resurrecting its ancestors in the family Solanaceae. SCIENCE ADVANCES 2022; 8:eabm6871. [PMID: 35427154 PMCID: PMC9012466 DOI: 10.1126/sciadv.abm6871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plants and photosynthetic organisms have a remarkably inefficient enzyme named Rubisco that fixes atmospheric CO2 into organic compounds. Understanding how Rubisco has evolved in response to past climate change is important for attempts to adjust plants to future conditions. In this study, we developed a computational workflow to assemble de novo both large and small subunits of Rubisco enzymes from transcriptomics data. Next, we predicted sequences for ancestral Rubiscos of the (nightshade) family Solanaceae and characterized their kinetics after coexpressing them in Escherichia coli. Predicted ancestors of C3 Rubiscos were identified that have superior kinetics and excellent potential to help plants adapt to anthropogenic climate change. Our findings also advance understanding of the evolution of Rubisco's catalytic traits.
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Cui H. Challenges and Approaches to Crop Improvement Through C3-to-C4 Engineering. FRONTIERS IN PLANT SCIENCE 2021; 12:715391. [PMID: 34594351 PMCID: PMC8476962 DOI: 10.3389/fpls.2021.715391] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/06/2021] [Indexed: 05/24/2023]
Abstract
With a rapidly growing world population and dwindling natural resources, we are now facing the enormous challenge of increasing crop yields while simultaneously improving the efficiency of resource utilization. Introduction of C4 photosynthesis into C3 crops is widely accepted as a key strategy to meet this challenge because C4 plants are more efficient than C3 plants in photosynthesis and resource usage, particularly in hot climates, where the potential for productivity is high. Lending support to the feasibility of this C3-to-C4 engineering, evidence indicates that C4 photosynthesis has evolved from C3 photosynthesis in multiple lineages. Nevertheless, C3-to-C4 engineering is not an easy task, as several features essential to C4 photosynthesis must be introduced into C3 plants. One such feature is the spatial separation of the two phases of photosynthesis (CO2 fixation and carbohydrate synthesis) into the mesophyll and bundle sheath cells, respectively. Another feature is the Kranz anatomy, characterized by a close association between the mesophyll and bundle sheath (BS) cells (1:1 ratio). These anatomical features, along with a C4-specific carbon fixation enzyme (PEPC), form a CO2-concentration mechanism that ensures a high photosynthetic efficiency. Much effort has been taken in the past to introduce the C4 mechanism into C3 plants, but none of these attempts has met with success, which is in my opinion due to a lack of system-level understanding and manipulation of the C3 and C4 pathways. As a prerequisite for the C3-to-C4 engineering, I propose that not only the mechanisms that control the Kranz anatomy and cell-type-specific expression in C3 and C4 plants must be elucidated, but also a good understanding of the gene regulatory network underlying C3 and C4 photosynthesis must be achieved. In this review, I first describe the past and current efforts to increase photosynthetic efficiency in C3 plants and their limitations; I then discuss a systems approach to tackling down this challenge, some practical issues, and recent technical innovations that would help us to solve these problems.
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Affiliation(s)
- Hongchang Cui
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
- College of Life Science, Northwest Science University of Agriculture and Forestry, Yangling, China
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Schierenbeck M, Alqudah AM, Lohwasser U, Tarawneh RA, Simón MR, Börner A. Genetic dissection of grain architecture-related traits in a winter wheat population. BMC PLANT BIOLOGY 2021; 21:417. [PMID: 34507551 PMCID: PMC8431894 DOI: 10.1186/s12870-021-03183-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 08/20/2021] [Indexed: 05/08/2023]
Abstract
BACKGROUND The future productivity of wheat (T. aestivum L.) as the most grown crop worldwide is of utmost importance for global food security. Thousand kernel weight (TKW) in wheat is closely associated with grain architecture-related traits, e.g. kernel length (KL), kernel width (KW), kernel area (KA), kernel diameter ratio (KDR), and factor form density (FFD). Discovering the genetic architecture of natural variation in these traits, identifying QTL and candidate genes are the main aims of this study. Therefore, grain architecture-related traits in 261 worldwide winter accessions over three field-year experiments were evaluated. RESULTS Genome-wide association analysis using 90K SNP array in FarmCPU model revealed several interesting genomic regions including 17 significant SNPs passing false discovery rate threshold and strongly associated with the studied traits. Four of associated SNPs were physically located inside candidate genes within LD interval e.g. BobWhite_c5872_589 (602,710,399 bp) found to be inside TraesCS6A01G383800 (602,699,767-602,711,726 bp). Further analysis reveals the four novel candidate genes potentially involved in more than one grain architecture-related traits with a pleiotropic effects e.g. TraesCS6A01G383800 gene on 6A encoding oxidoreductase activity was associated with TKW and KA. The allelic variation at the associated SNPs showed significant differences betweeen the accessions carying the wild and mutated alleles e.g. accessions carying C allele of BobWhite_c5872_589, TraesCS6A01G383800 had significantly higher TKW than the accessions carying T allele. Interestingly, these genes were highly expressed in the grain-tissues, demonstrating their pivotal role in controlling the grain architecture. CONCLUSIONS These results are valuable for identifying regions associated with kernel weight and dimensions and potentially help breeders in improving kernel weight and architecture-related traits in order to increase wheat yield potential and end-use quality.
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Affiliation(s)
- Matías Schierenbeck
- Genebank Department, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstr 3, D-06466, Seeland, Germany.
- Cereals, Faculty of Agricultural Sciences and Forestry, National University of La Plata, La Plata, Argentina.
- CONICET CCT La Plata. La Plata, Buenos Aires, Argentina.
| | - Ahmad M Alqudah
- Department of Agroecology, Aarhus University at Flakkebjerg, Forsøgsvej 1, 4200, Slagelse, Denmark.
| | - Ulrike Lohwasser
- Genebank Department, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstr 3, D-06466, Seeland, Germany
| | - Rasha A Tarawneh
- Genebank Department, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstr 3, D-06466, Seeland, Germany
| | - María Rosa Simón
- Cereals, Faculty of Agricultural Sciences and Forestry, National University of La Plata, La Plata, Argentina
- CONICET CCT La Plata. La Plata, Buenos Aires, Argentina
| | - Andreas Börner
- Genebank Department, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstr 3, D-06466, Seeland, Germany
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Chen S, Qiu G. Overexpression of seagrass DnaJ gene ZjDjB1 enhances the thermotolerance of transgenic arabidopsis thaliana. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2021; 27:2043-2055. [PMID: 34629777 PMCID: PMC8484434 DOI: 10.1007/s12298-021-01063-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/03/2021] [Accepted: 09/07/2021] [Indexed: 05/06/2023]
Abstract
Seagrass meadows are one of the most important marine resources that grow along the coast. They provide habitat and a food source for animals. They also protect the coast, fix sediment and purify seawater. In the current period of global climate change, anomalies in coastal water temperatures are increasing. A sudden increase in water temperature owing to a heat wave can have a profound effect on seagrass. Zostera japonica is a type of intertidal seagrasses, which is exposed to the air at low tide. High temperatures in the summer often lead to a decline in seagrass meadows. DnaJ proteins, also known as J proteins, are a family of conserved chaperone proteins. They are designated as J proteins because they contain a highly conserved J domain. They function as chaperones of heat shock proteins in organisms. In this study, the role of DnaJ protein (ZjDjB1) of Z. japonica under heat stress was studied. ZjDjB1 was localized to the cytoplasm and nucleus. The overexpression of ZjDjB1 in Arabidopsis thaliana results in an increase in thermotolerance and a decrease in the accumulation of reactive oxygen species and also a reduction in membrane damage. ZjDjB1 may achieve this goal by maintaining a low activity of proteolytic enzymes.
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Affiliation(s)
- Siting Chen
- Guangxi Key Lab of Mangrove Conservation and Utilization, Guangxi Mangrove Research Center, Guangxi Academy of Sciences, Beihai, 536007 Guangxi China
| | - Guanglong Qiu
- Guangxi Key Lab of Mangrove Conservation and Utilization, Guangxi Mangrove Research Center, Guangxi Academy of Sciences, Beihai, 536007 Guangxi China
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14
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Wietrzynski W, Traverso E, Wollman FA, Wostrikoff K. The state of oligomerization of Rubisco controls the rate of synthesis of the Rubisco large subunit in Chlamydomonas reinhardtii. THE PLANT CELL 2021; 33:1706-1727. [PMID: 33625514 PMCID: PMC8254502 DOI: 10.1093/plcell/koab061] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/12/2021] [Indexed: 05/22/2023]
Abstract
Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is present in all photosynthetic organisms and is a key enzyme for photosynthesis-driven life on Earth. Its most prominent form is a hetero-oligomer in which small subunits (SSU) stabilize the core of the enzyme built from large subunits (LSU), yielding, after a chaperone-assisted multistep assembly process, an LSU8SSU8 hexadecameric holoenzyme. Here we use Chlamydomonas reinhardtii and a combination of site-directed mutants to dissect the multistep biogenesis pathway of Rubisco in vivo. We identify assembly intermediates, in two of which LSU are associated with the RAF1 chaperone. Using genetic and biochemical approaches we further unravel a major regulation process during Rubisco biogenesis, in which LSU translation is controlled by its ability to assemble with the SSU, via the mechanism of control by epistasy of synthesis (CES). Altogether this leads us to propose a model whereby the last assembly intermediate, an LSU8-RAF1 complex, provides the platform for SSU binding to form the Rubisco enzyme, and when SSU is not available, converts to a key regulatory form that exerts negative feedback on the initiation of LSU translation.
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Affiliation(s)
- Wojciech Wietrzynski
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Eleonora Traverso
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
| | - Francis-André Wollman
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
| | - Katia Wostrikoff
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
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15
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Hotto AM, Salesse-Smith C, Lin M, Busch FA, Simpson I, Stern DB. Rubisco production in maize mesophyll cells through ectopic expression of subunits and chaperones. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4930-4937. [PMID: 33928359 DOI: 10.1093/jxb/erab189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
C4 plants, such as maize, strictly compartmentalize Rubisco to bundle sheath chloroplasts. The molecular basis for the restriction of Rubisco from the more abundant mesophyll chloroplasts is not fully understood. Mesophyll chloroplasts transcribe the Rubisco large subunit gene and, when normally quiescent transcription of the nuclear Rubisco small subunit gene family is overcome by ectopic expression, mesophyll chloroplasts still do not accumulate measurable Rubisco. Here we show that a combination of five ubiquitin promoter-driven nuclear transgenes expressed in maize leads to mesophyll accumulation of assembled Rubisco. These encode the Rubisco large and small subunits, Rubisco assembly factors 1 and 2, and the assembly factor Bundle sheath defective 2. In these plants, Rubisco large subunit accumulates in mesophyll cells, and appears to be assembled into a holoenzyme capable of binding the substrate analog CABP (carboxyarabinitol bisphosphate). Isotope discrimination assays suggest, however, that mesophyll Rubisco is not participating in carbon assimilation in these plants, most probably due to a lack of the substrate ribulose 1,5-bisphosphate and/or Rubisco activase. Overall, this work defines a minimal set of Rubisco assembly factors in planta and may help lead to methods of regulating the C4 pathway.
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Affiliation(s)
| | | | - Myat Lin
- Cornell University, Ithaca, NY, USA
| | - Florian A Busch
- School of Biosciences, and Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, UK
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
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16
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ZnJ6 Is a Thylakoid Membrane DnaJ-Like Chaperone with Oxidizing Activity in Chlamydomonas reinhardtii. Int J Mol Sci 2021; 22:ijms22031136. [PMID: 33498879 PMCID: PMC7865324 DOI: 10.3390/ijms22031136] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 11/28/2022] Open
Abstract
Assembly of photosynthetic complexes is sensitive to changing light intensities, drought and pathogens, each of which induces a redox imbalance that requires the assistance of specific chaperones to maintain protein structure. Here we report a thylakoid membrane-associated DnaJ-like protein, ZnJ6 (Cre06.g251716.t1.2), in Chlamydomonas reinhardtii. The protein has four CXXCX(G)X(G) motifs that form two zinc fingers (ZFs). Site-directed mutagenesis (Cys > Ser) eliminates the ability to bind zinc. An intact ZF is required for ZnJ6 stability at elevated temperatures. Chaperone assays with recombinant ZnJ6 indicate that it has holding and oxidative activities. ZnJ6 is unable to reduce the disulfide bonds of insulin but prevents its aggregation in a reducing environment. It also assists in the reactivation of reduced denatured RNaseA, possibly by its oxidizing activity. ZnJ6 pull-down assays revealed interactions with oxidoreductases, photosynthetic proteins and proteases. In vivo experiments with a C. reinhardtii insertional mutant (∆ZnJ6) indicate enhanced tolerance to oxidative stress but increased sensitivity to heat and reducing conditions. Moreover, ∆ZnJ6 has reduced photosynthetic efficiency shown by the Chlorophyll fluorescence transient. Taken together, we identify a role for this thylakoid-associated DnaJ-like oxidizing chaperone that assists in the prevention of protein misfolding and aggregation, thus contributing to stress endurance, redox maintenance and photosynthetic balance.
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17
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Feiz L, Strickler SR, van Eck J, Mao L, Movahed N, Taylor C, Gourabathini P, Fei Z, Stern DB. Setaria viridis chlorotic and seedling-lethal mutants define critical functions for chloroplast gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:917-931. [PMID: 32812296 DOI: 10.1111/tpj.14968] [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: 10/01/2018] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Deep insights into chloroplast biogenesis have been obtained by mutant analysis; however, in C4 plants a relevant mutant collection has only been developed and exploited for maize. Here, we report the initial characterization of an ethyl methyl sulfonate-induced mutant population for the C4 model Setaria viridis. Approximately 1000 M2 families were screened for the segregation of pale-green seedlings in the M3 generation, and a subset of these was identified to be deficient in post-transcriptional steps of chloroplast gene expression. Causative mutations were identified for three lines using deep sequencing-based bulked segregant analysis, and in one case confirmed by transgenic complementation. Using chloroplast RNA-sequencing and other molecular assays, we describe phenotypes of mutants deficient in PSRP7, a plastid-specific ribosomal protein, OTP86, an RNA editing factor, and cpPNP, the chloroplast isozyme of polynucleotide phosphorylase. The psrp mutant is globally defective in chloroplast translation, and has varying deficiencies in the accumulation of chloroplast-encoded proteins. The otp86 mutant, like its Arabidopsis counterpart, is specifically defective in editing of the rps14 mRNA; however, the conditional pale-green mutant phenotype contrasts with the normal growth of the Arabidopsis mutant. The pnp mutant exhibited multiple defects in 3' end maturation as well as other qualitative changes in the chloroplast RNA population. Overall, our collection opens the door to global analysis of photosynthesis and early seedling development in an emerging C4 model.
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Affiliation(s)
- Leila Feiz
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
| | | | - Joyce van Eck
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
| | - Linyong Mao
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Department of Biochemistry and Molecular Biology, Howard University, Washington, DC, 20059, USA
| | - Navid Movahed
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Q² Solutions, Ithaca, New York, 14850, USA
| | - Caroline Taylor
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Lansing High School, Lansing, New York, 14882, USA
- Cornell University, Ithaca, New York, New York, 14850, USA
| | | | - Zhangjun Fei
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
| | - David B Stern
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
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18
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Lin MT, Stone WD, Chaudhari V, Hanson MR. Small subunits can determine enzyme kinetics of tobacco Rubisco expressed in Escherichia coli. NATURE PLANTS 2020; 6:1289-1299. [PMID: 32929197 DOI: 10.1038/s41477-020-00761-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 07/28/2020] [Indexed: 05/19/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) catalyses the first step in carbon fixation and is a strategic target for improving photosynthetic efficiency. In plants, Rubisco is composed of eight large and eight small subunits, and its biogenesis requires multiple chaperones. Here, we optimized a system to produce tobacco Rubisco in Escherichia coli by coexpressing chaperones in autoinduction medium. We successfully assembled tobacco Rubisco in E. coli with each small subunit that is normally encoded by the nuclear genome. Even though each enzyme carries only a single type of small subunit in E. coli, the enzymes exhibit carboxylation kinetics that are very similar to the carboxylation kinetics of the native Rubisco. Tobacco Rubisco assembled with a recently discovered trichome small subunit has a higher catalytic rate and a lower CO2 affinity compared with Rubisco complexes that are assembled with other small subunits. Our E. coli expression system will enable the analysis of features of both subunits of Rubisco that affect its kinetic properties.
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Affiliation(s)
- Myat T Lin
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - William D Stone
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | | | - Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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19
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Chaperone Machineries of Rubisco – The Most Abundant Enzyme. Trends Biochem Sci 2020; 45:748-763. [DOI: 10.1016/j.tibs.2020.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/19/2020] [Accepted: 05/04/2020] [Indexed: 12/14/2022]
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20
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Abstract
C4 photosynthesis evolved multiple times independently from ancestral C3 photosynthesis in a broad range of flowering land plant families and in both monocots and dicots. The evolution of C4 photosynthesis entails the recruitment of enzyme activities that are not involved in photosynthetic carbon fixation in C3 plants to photosynthesis. This requires a different regulation of gene expression as well as a different regulation of enzyme activities in comparison to the C3 context. Further, C4 photosynthesis relies on a distinct leaf anatomy that differs from that of C3, requiring a differential regulation of leaf development in C4. We summarize recent progress in the understanding of C4-specific features in evolution and metabolic regulation in the context of C4 photosynthesis.
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Affiliation(s)
- Urte Schlüter
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; ,
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; ,
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21
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Tominaga J, Takahashi S, Sakamoto A, Shimada H. Arabidopsis BSD2 reveals a novel redox regulation of Rubisco physiology in vivo. PLANT SIGNALING & BEHAVIOR 2020; 15:1740873. [PMID: 32233721 PMCID: PMC7194379 DOI: 10.1080/15592324.2020.1740873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
Plants need light energy to drive photosynthesis, but excess energy leads to the production of harmful reactive oxygen species (ROS), resulting in oxidative inactivation of target enzymes, including the photosynthetic CO2-fixing enzyme, ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been demonstrated in vitro that oxidatively inactivated Rubisco can be reactivated by the addition of reducing agents. Busch et al. (in The Plant Journal, doi: 10.1111/tpj.14617, 2020) recently demonstrated that bundle-sheath defective 2 (BSD2), a stroma-targeted protein formerly known as a late-assembly chaperone for Rubisco biosynthesis, can be responsible for such reactivation in vivo. Here, we propose a working model of the novel redox regulation in Rubisco activity. Redox of Rubisco may be a new target for improving photosynthesis.
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Affiliation(s)
- Jun Tominaga
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Shunichi Takahashi
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan
| | - Atsushi Sakamoto
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Hiroshi Shimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
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22
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Busch FA, Tominaga J, Muroya M, Shirakami N, Takahashi S, Yamori W, Kitaoka T, Milward SE, Nishimura K, Matsunami E, Toda Y, Higuchi C, Muranaka A, Takami T, Watanabe S, Kinoshita T, Sakamoto W, Sakamoto A, Shimada H. Overexpression of BUNDLE SHEATH DEFECTIVE 2 improves the efficiency of photosynthesis and growth in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:129-137. [PMID: 31755157 PMCID: PMC7217058 DOI: 10.1111/tpj.14617] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 11/01/2019] [Accepted: 11/12/2019] [Indexed: 05/16/2023]
Abstract
Bundle Sheath Defective 2, BSD2, is a stroma-targeted protein initially identified as a factor required for the biogenesis of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) in maize. Plants and algae universally have a homologous gene for BSD2 and its deficiency causes a RuBisCO-less phenotype. As RuBisCO can be the rate-limiting step in CO2 assimilation, the overexpression of BSD2 might improve photosynthesis and productivity through the accumulation of RuBisCO. To examine this hypothesis, we produced BSD2 overexpression lines in Arabidopsis. Compared with wild type, the BSD2 overexpression lines BSD2ox-2 and BSD2ox-3 expressed 4.8-fold and 8.8-fold higher BSD2 mRNA, respectively, whereas the empty-vector (EV) harbouring plants had a comparable expression level. The overexpression lines showed a significantly higher CO2 assimilation rate per available CO2 and productivity than EV plants. The maximum carboxylation rate per total catalytic site was accelerated in the overexpression lines, while the number of total catalytic sites and RuBisCO content were unaffected. We then isolated recombinant BSD2 (rBSD2) from E. coli and found that rBSD2 reduces disulfide bonds using reductants present in vivo, for example glutathione, and that rBSD2 has the ability to reactivate RuBisCO that has been inactivated by oxidants. Furthermore, 15% of RuBisCO freshly isolated from leaves of EV was oxidatively inactivated, as compared with 0% in BSD2-overexpression lines, suggesting that the overexpression of BSD2 maintains RuBisCO to be in the reduced active form in vivo. Our results demonstrated that the overexpression of BSD2 improves photosynthetic efficiency in Arabidopsis and we conclude that it is involved in mediating RuBisCO activation.
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Affiliation(s)
- Florian A. Busch
- Research School of BiologyAustralian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Jun Tominaga
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
| | - Masato Muroya
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
| | - Norihiko Shirakami
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
| | - Shunichi Takahashi
- Research School of BiologyAustralian National UniversityCanberraAustralian Capital Territory2601Australia
- Present address:
Division of Environmental PhotobiologyNational Institute for Basic BiologyOkazaki444‐8585Japan
| | - Wataru Yamori
- Graduate School of ScienceUniversity of TokyoBunkyo‐kuTokyo113‐0033Japan
| | - Takuya Kitaoka
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityChikusaNagoya464‐8602Japan
| | - Sara E. Milward
- Research School of BiologyAustralian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Kohji Nishimura
- Department of Molecular and Functional GenomicsInterdisciplinary Center for Science ResearchOrganization of ResearchShimane UniversityNishikawatsu 1060Matsue690‐8504Japan
| | - Erika Matsunami
- Department of Molecular and Functional GenomicsInterdisciplinary Center for Science ResearchOrganization of ResearchShimane UniversityNishikawatsu 1060Matsue690‐8504Japan
| | - Yosuke Toda
- Graduate School of ScienceUniversity of TokyoBunkyo‐kuTokyo113‐0033Japan
| | - Chikako Higuchi
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
| | - Atsuko Muranaka
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
| | - Tsuneaki Takami
- Institute of Plant Science and ResourcesOkayama UniversityKurashikiOkayama710‐0046Japan
| | - Shunsuke Watanabe
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
- Present address:
RIKEN Center for Sustainable Resource ScienceSuehiro‐cho, 1‐7‐22, Tsurumi‐kuYokohamaKanagawa230‐0045Japan
| | - Toshinori Kinoshita
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityChikusaNagoya464‐8602Japan
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityChikusaNagoya464‐8602Japan
| | - Wataru Sakamoto
- Institute of Plant Science and ResourcesOkayama UniversityKurashikiOkayama710‐0046Japan
| | - Atsushi Sakamoto
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
| | - Hiroshi Shimada
- Graduate School of Integrated Sciences for LifeHiroshima University1‐3‐1 KagamiyamaHigashi‐Hiroshima739‐8526Japan
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23
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Li H, Bai M, Jiang X, Shen R, Wang H, Wang H, Wu H. Cytological evidence of BSD2 functioning in both chloroplast division and dimorphic chloroplast formation in maize leaves. BMC PLANT BIOLOGY 2020; 20:17. [PMID: 31918680 PMCID: PMC6953307 DOI: 10.1186/s12870-019-2219-7] [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: 09/25/2019] [Accepted: 12/26/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND Maize bsd2 (bundle sheath defective2) is a classical C4 mutant with defective C4 photosynthesis, accompanied with reduced accumulation of Rubisco (ribulose bisphosphate carboxylase oxygenase) and aberrant mature chloroplast morphology in the bundle sheath (BS) cells. However, as a hypothetical chloroplast chaperone, the effects of BSD2 on C4 chloroplast development have not been fully examined yet, which precludes a full appreciation of BSD2 function in C4 photosynthesis. The aims of our study are to find out the role ofBSD2 in regulating chloroplasts development in maize leaves, and to add new insights into our understanding of C4 biology. RESULTS We found that at the chloroplast maturation stage, the thylakoid membranes of chloroplasts in the BS and mesophyll (M) cells became significantly looser, and the granaof chloroplasts in the M cells became thinner stacking in the bsd2 mutant when compared with the wildtype plant. Moreover, at the early chloroplast development stage, the number of dividing chloroplasts and the chloroplast division rate are both reduced in the bsd2 mutant, compared with wild type. Quantitative reverse transcriptase-PCR analysis revealed that the expression of both thylakoid formation-related genesand chloroplast division-related genes is significantly reduced in the bsd2 mutants. Further, we showed that BSD2 interacts physically with the large submit of Rubisco (LS) in Bimolecular Fluorescence Complementation assay. CONCLUSIONS Our combined results suggest that BSD2 plays an essential role in regulating the division and differentiation of the dimorphic BS and M chloroplasts, and that it acts at a post-transcriptional level to regulate LS stability or assembly of Rubisco.
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Affiliation(s)
- Heying Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Mei Bai
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Xingshan Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Rongxin Shen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Huina Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Haiyang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Hong Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642 China
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24
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Wessendorf RL, Lu Y. Photosynthetic characterization of transgenic Synechocystis expressing a plant thiol/disulfide-modulating protein. PLANT SIGNALING & BEHAVIOR 2019; 15:1709708. [PMID: 31889463 PMCID: PMC7053882 DOI: 10.1080/15592324.2019.1709708] [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: 10/28/2019] [Revised: 12/18/2019] [Accepted: 12/22/2019] [Indexed: 06/10/2023]
Abstract
A previous study showed that introducing an Arabidopsis thaliana thiol/disulfide-modulating protein, Low Quantum Yield of Photosystem II 1 (LQY1), into the cyanobacterium Synechocystis sp. PCC6803 increased the efficiency of Photosystem II (PSII) photochemistry. In the present study, the authors provided additional evidence for the role of AtLQY1 in improving PSII photochemical efficiency and cell growth. Light response curve analysis showed that AtLQY1-expressing Synechocystis grown at a moderate growth light intensity (50 µmol photons m-2 s-1) had higher minimal, maximal, and variable fluorescence than the empty-vector control, under a wide range of actinic light intensities. Light induction and dark recovery curves demonstrated that AtLQY1-expressing Synechocystis grown at the moderate growth light intensity had higher effective PSII quantum yield, higher photochemical quenching, lower regulated heat dissipation (non-photochemical quenching), low amounts of reduced plastoquinone, and higher amounts of oxidized plastoquinone than the empty-vector control. Furthermore, growth curve analysis indicated that AtLQY1-expressing Synechocystis grew faster than the empty-vector control at the moderate growth light intensity. These results suggest that transgenic expression of AtLQY1 in Synechocystis significantly improves PSII photochemical efficiency and overall cell growth.
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Affiliation(s)
- Ryan L. Wessendorf
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | - Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
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25
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Conlan B, Birch R, Kelso C, Holland S, De Souza AP, Long SP, Beck JL, Whitney SM. BSD2 is a Rubisco-specific assembly chaperone, forms intermediary hetero-oligomeric complexes, and is nonlimiting to growth in tobacco. PLANT, CELL & ENVIRONMENT 2019; 42:1287-1301. [PMID: 30375663 DOI: 10.1111/pce.13473] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/30/2018] [Accepted: 10/22/2018] [Indexed: 05/28/2023]
Abstract
The folding and assembly of Rubisco large and small subunits into L8 S8 holoenzyme in chloroplasts involves many auxiliary factors, including the chaperone BSD2. Here we identify apparent intermediary Rubisco-BSD2 assembly complexes in the model C3 plant tobacco. We show BSD2 and Rubisco content decrease in tandem with leaf age with approximately half of the BSD2 in young leaves (~70 nmol BSD2 protomer.m2 ) stably integrated in putative intermediary Rubisco complexes that account for <0.2% of the L8 S8 pool. RNAi-silencing BSD2 production in transplastomic tobacco producing bacterial L2 Rubisco had no effect on leaf photosynthesis, cell ultrastructure, or plant growth. Genetic crossing the same RNAi-bsd2 alleles into wild-type tobacco however impaired L8 S8 Rubisco production and plant growth, indicating the only critical function of BSD2 is in Rubisco biogenesis. Agrobacterium mediated transient expression of tobacco, Arabidopsis, or maize BSD2 reinstated Rubisco biogenesis in BSD2-silenced tobacco. Overexpressing BSD2 in tobacco chloroplasts however did not alter Rubisco content, activation status, leaf photosynthesis rate, or plant growth in the field or in the glasshouse at 20°C or 35°C. Our findings indicate BSD2 functions exclusively in Rubisco biogenesis, can efficiently facilitate heterologous plant Rubisco assembly, and is produced in amounts nonlimiting to tobacco growth.
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Affiliation(s)
- Brendon Conlan
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Rosemary Birch
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Celine Kelso
- School of Chemistry, Molecular Horizons, University of Wollongong, New South Wales, Australia
| | - Sophie Holland
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Amanda P De Souza
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
| | - Stephen P Long
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Jennifer L Beck
- School of Chemistry, Molecular Horizons, University of Wollongong, New South Wales, Australia
| | - Spencer M Whitney
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
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Wilson RH, Thieulin-Pardo G, Hartl FU, Hayer-Hartl M. Improved recombinant expression and purification of functional plant Rubisco. FEBS Lett 2019; 593:611-621. [PMID: 30815863 PMCID: PMC6593764 DOI: 10.1002/1873-3468.13352] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 02/24/2019] [Accepted: 02/25/2019] [Indexed: 12/22/2022]
Abstract
Improving the performance of the key photosynthetic enzyme Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) by protein engineering is a critical strategy for increasing crop yields. The extensive chaperone requirement of plant Rubisco for folding and assembly has long been an impediment to this goal. Production of plant Rubisco in Escherichia coli requires the coexpression of the chloroplast chaperonin and four assembly factors. Here, we demonstrate that simultaneous expression of Rubisco and chaperones from a T7 promotor produces high levels of functional enzyme. Expressing the small subunit of Rubisco with a C-terminal hexahistidine-tag further improved assembly, resulting in a ~ 12-fold higher yield than the previously published procedure. The expression system described here provides a platform for the efficient production and engineering of plant Rubisco.
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Affiliation(s)
- Robert H Wilson
- Chaperonin-assisted Protein Folding Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Gabriel Thieulin-Pardo
- Chaperonin-assisted Protein Folding Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Franz-Ulrich Hartl
- Cellular Biochemistry Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Manajit Hayer-Hartl
- Chaperonin-assisted Protein Folding Group, Max Planck Institute of Biochemistry, Martinsried, Germany
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27
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Salesse-Smith CE, Sharwood RE, Busch FA, Kromdijk J, Bardal V, Stern DB. Overexpression of Rubisco subunits with RAF1 increases Rubisco content in maize. NATURE PLANTS 2018; 4:802-810. [PMID: 30287949 DOI: 10.1038/s41477-018-0252-4] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/15/2018] [Indexed: 05/21/2023]
Abstract
Rubisco catalyses a rate-limiting step in photosynthesis and has long been a target for improvement due to its slow turnover rate. An alternative to modifying catalytic properties of Rubisco is to increase its abundance within C4 plant chloroplasts, which might increase activity and confer a higher carbon assimilation rate. Here, we overexpress the Rubisco large (LS) and small (SS) subunits with the Rubisco assembly chaperone RUBISCO ASSEMBLY FACTOR 1 (RAF1). While overexpression of LS and/or SS had no discernable impact on Rubisco content, addition of RAF1 overexpression resulted in a >30% increase in Rubisco content. Gas exchange showed a 15% increase in CO2 assimilation (ASAT) in UBI-LSSS-RAF1 transgenic plants, which correlated with increased fresh weight and in vitro Vcmax calculations. The divergence of Rubisco content and assimilation could be accounted for by the Rubisco activation state, which decreased up to 23%, suggesting that Rubisco activase may be limiting Vcmax, and impinging on the realization of photosynthetic potential from increased Rubisco content.
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Affiliation(s)
| | - Robert E Sharwood
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Florian A Busch
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Johannes Kromdijk
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
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Sedelnikova OV, Hughes TE, Langdale JA. Understanding the Genetic Basis of C 4 Kranz Anatomy with a View to Engineering C 3 Crops. Annu Rev Genet 2018; 52:249-270. [PMID: 30208293 DOI: 10.1146/annurev-genet-120417-031217] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One of the most remarkable examples of convergent evolution is the transition from C3 to C4 photosynthesis, an event that occurred on over 60 independent occasions. The evolution of C4 is particularly noteworthy because of the complexity of the developmental and metabolic changes that took place. In most cases, compartmentalized metabolic reactions were facilitated by the development of a distinct leaf anatomy known as Kranz. C4 Kranz anatomy differs from ancestral C3 anatomy with respect to vein spacing patterns across the leaf, cell-type specification around veins, and cell-specific organelle function. Here we review our current understanding of how Kranz anatomy evolved and how it develops, with a focus on studies that are dissecting the underlying genetic mechanisms. This research field has gained prominence in recent years because understanding the genetic regulation of Kranz may enable the C3-to-C4 transition to be engineered, an endeavor that would significantly enhance crop productivity.
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Affiliation(s)
- Olga V Sedelnikova
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom; , ,
| | - Thomas E Hughes
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom; , ,
| | - Jane A Langdale
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom; , ,
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29
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Fukayama H, Mizumoto A, Ueguchi C, Katsunuma J, Morita R, Sasayama D, Hatanaka T, Azuma T. Expression level of Rubisco activase negatively correlates with Rubisco content in transgenic rice. PHOTOSYNTHESIS RESEARCH 2018; 137:465-474. [PMID: 29846871 DOI: 10.1007/s11120-018-0525-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/25/2018] [Indexed: 05/24/2023]
Abstract
The relationship between ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase (Rca) levels was studied using transgenic rice overexpressing maize Rca (OX-mRca) and knockdown transgenic rice expressing antisense Rca (KD-Rca). The ratio of Rubisco to total soluble protein was lower in OX-mRca, whereas it was higher in KD-Rca than in WT, indicating that Rca expression was negatively correlated with Rubisco content. The expressions of other Calvin-Benson-Bassham cycle enzymes such as sedoheptulose-1,7-bisphosphatase and phosphoribulokinase analyzed by immunoblotting did not show such a negative correlation with Rca, suggesting that the effect of Rca on protein expression may be specific for Rubisco. Although Rubisco content was decreased in OX-mRca, the transcript levels of the Rubisco large subunit (OsRbcL) and the Rubisco small subunit mostly increased in OX-mRca as well as in KD-Rca. Additionally, polysome loading of OsRbcL was slightly higher in OX-mRca than it was in WT, suggesting that the OsRbcL translation activity was likely stimulated by overexpression of Rca. 35S-methionine labeling experiments demonstrated that there was no significant difference in the stability of newly synthesized Rubisco among genotypes. However, 35S-methionine-labeled Rubisco was marginally decreased in OX-mRca and increased in KD-Rca compared to the WT. These results suggest that Rca negatively affects the Rubisco content, possibly in the synthesis step.
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Affiliation(s)
- Hiroshi Fukayama
- Laboratory of Tropical Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan.
| | - Akina Mizumoto
- Laboratory of Tropical Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Chiaki Ueguchi
- Laboratory of Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Jun Katsunuma
- Laboratory of Crop Science, Faculty of Agriculture, Kobe University, Kobe, 657-8501, Japan
| | - Ryutaro Morita
- Laboratory of Tropical Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Daisuke Sasayama
- Laboratory of Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Tomoko Hatanaka
- Laboratory of Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Tetsushi Azuma
- Laboratory of Tropical Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
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Aigner H, Wilson RH, Bracher A, Calisse L, Bhat JY, Hartl FU, Hayer-Hartl M. Plant RuBisCo assembly in E. coli with five chloroplast chaperones including BSD2. Science 2018; 358:1272-1278. [PMID: 29217567 DOI: 10.1126/science.aap9221] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/17/2017] [Indexed: 01/06/2023]
Abstract
Plant RuBisCo, a complex of eight large and eight small subunits, catalyzes the fixation of CO2 in photosynthesis. The low catalytic efficiency of RuBisCo provides strong motivation to reengineer the enzyme with the goal of increasing crop yields. However, genetic manipulation has been hampered by the failure to express plant RuBisCo in a bacterial host. We achieved the functional expression of Arabidopsis thaliana RuBisCo in Escherichia coli by coexpressing multiple chloroplast chaperones. These include the chaperonins Cpn60/Cpn20, RuBisCo accumulation factors 1 and 2, RbcX, and bundle-sheath defective-2 (BSD2). Our structural and functional analysis revealed the role of BSD2 in stabilizing an end-state assembly intermediate of eight RuBisCo large subunits until the small subunits become available. The ability to produce plant RuBisCo recombinantly will facilitate efforts to improve the enzyme through mutagenesis.
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Affiliation(s)
- H Aigner
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - R H Wilson
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - A Bracher
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - L Calisse
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - J Y Bhat
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - F U Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - M Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany.
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31
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Vitlin Gruber A, Feiz L. Rubisco Assembly in the Chloroplast. Front Mol Biosci 2018; 5:24. [PMID: 29594130 PMCID: PMC5859369 DOI: 10.3389/fmolb.2018.00024] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/27/2018] [Indexed: 01/13/2023] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step in the Calvin-Benson cycle, which transforms atmospheric carbon into a biologically useful carbon source. The slow catalytic rate of Rubisco and low substrate specificity necessitate the production of high levels of this enzyme. In order to engineer a more efficient plant Rubisco, we need to better understand its folding and assembly process. Form I Rubisco, found in green algae and vascular plants, is a hexadecamer composed of 8 large subunits (RbcL), encoded by the chloroplast genome and 8 small, nuclear-encoded subunits (RbcS). Unlike its cyanobacterial homolog, which can be reconstituted in vitro or in E. coli, assisted by bacterial chaperonins (GroEL-GroES) and the RbcX chaperone, biogenesis of functional chloroplast Rubisco requires Cpn60-Cpn20, the chloroplast homologs of GroEL-GroES, and additional auxiliary factors, including Rubisco accumulation factor 1 (Raf1), Rubisco accumulation factor 2 (Raf2) and Bundle sheath defective 2 (Bsd2). The discovery and characterization of these factors paved the way for Arabidopsis Rubisco assembly in E. coli. In the present review, we discuss the uniqueness of hetero-oligomeric chaperonin complex for RbcL folding, as well as the sequential or concurrent actions of the post-chaperonin chaperones in holoenzyme assembly. The exact stages at which each assembly factor functions are yet to be determined. Expression of Arabidopsis Rubisco in E. coli provided some insight regarding the potential roles for Raf1 and RbcX in facilitating RbcL oligomerization, for Bsd2 in stabilizing the oligomeric core prior to holoenzyme assembly, and for Raf2 in interacting with both RbcL and RbcS. In the long term, functional characterization of each known factor along with the potential discovery and characterization of additional factors will set the stage for designing more efficient plants, with a greater biomass, for use in biofuels and sustenance.
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Affiliation(s)
- Anna Vitlin Gruber
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Leila Feiz
- Boyce Thompson Institute, Cornell University, Ithaca, NY, United States
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Doron L, Goloubinoff P, Shapira M. ZnJ2 Is a Member of a Large Chaperone Family in the Chloroplast of Photosynthetic Organisms that Features a DnaJ-Like Zn-Finger Domain. Front Mol Biosci 2018; 5:2. [PMID: 29497613 PMCID: PMC5818400 DOI: 10.3389/fmolb.2018.00002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/08/2018] [Indexed: 11/13/2022] Open
Abstract
Photosynthesis is performed by large complexes, composed of subunits encoded by the nuclear and chloroplast genomes. Assembly is assisted by general and target-specific chaperones, but their mode of action is yet unclear. We formerly showed that ZnJ2 is an algal chaperone resembling BSD2 from land plants. In algae, it co-migrates with the rbcL transcript on chloroplast polysomes, suggesting it contributes to the de-novo synthesis of RbcL (Doron et al., 2014). ZnJ2 contains four CXXCXGXG motifs, comprising a canonical domain typical also of DnaJ-type I (DNAJA). It contributes to the binding of protein substrates to DnaK and promotes an independent oxidoreductase activity (Mattoo et al., 2014). To examine whether ZnJ2 has oxidoreductase activity, we used the RNaseA assay, which measures the oxidation-dependent reactivation of reduced-denatured RNaseA. Although ZnJ2 assisted the native refolding of reduced-denatured RNaseA, its activity was restricted to an oxidizing environment. Thus, ZnJ2 did not carry the exclusive responsibility for the formation of disulfide bridges, but contributed to the stabilization of its target polypeptides, until they reached their native state. A ZnJ2 cysteine deficient mutant maintained a similar holding chaperone activity as the wild-type and did not induce the formation of disulfide bonds. ZnJ2 is devoid of a J-domain. It thus does not belong to the J-domain co-chaperones that target protein substrates to DnaK. As expected, in vitro, its aggregation-prevention activity was not synergic to the ATP-fueled action of DnaK/DnaJ/GrpE in assisting the native refolding of denatured malate dehydrogenase, nor did it show an independent refolding activity. A phylogenetic analysis showed that ZnJ2 and BSD2 from land plants, are two different proteins belonging to a larger group containing a cysteine-rich domain, that also includes the DNAJAs. Members of this family are apparently involved in specific assembly of photosynthetic complexes in the chloroplast.
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Affiliation(s)
- Lior Doron
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Pierre Goloubinoff
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Michal Shapira
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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33
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Lin MT, Hanson MR. Red algal Rubisco fails to accumulate in transplastomic tobacco expressing Griffithsia monilis RbcL and RbcS genes. PLANT DIRECT 2018; 2:e00045. [PMID: 31245711 PMCID: PMC6508576 DOI: 10.1002/pld3.45] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/28/2018] [Accepted: 01/30/2018] [Indexed: 05/03/2023]
Abstract
In C3 plants, the carbon fixation step catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) represents a major rate-limiting step due to the competing oxygenation reaction, which leads to the energy-intensive photorespiration and lowers the overall photosynthetic efficiency. Hence, there is great biotechnological interest in replacing the Rubisco in C3 crops with a more efficient enzyme. The Rubisco enzymes from red algae are among the most attractive choices due to their remarkable preference for carboxylation over oxygenation reaction. However, the biogenesis of Rubisco is extremely complex. The Rubisco enzymes in plants, algae, and cyanobacteria are made up of eight large and eight small subunits. The folding of the large subunits and the assembly of the large subunits with the small subunits to form a functional holoenzyme require specific chaperonin complexes and assembly factors. As a result, previous success in expressing foreign Rubisco in plants has been limited to Rubisco large subunits from closely related plant species and simpler bacterial enzymes. In our previous work, we successfully replaced the Rubisco in tobacco with a cyanobacterial enzyme, which was able to support the phototrophic growth of the transgenic plants. In this work, we used the same approach to express the Rubisco subunits from the red alga Griffithsia monilis in tobacco chloroplasts in the absence of the tobacco Rubisco large subunit. Although the red algal Rubisco genes are being transcribed in tobacco chloroplasts, the transgenic plants lack functional Rubisco and can only grow in a medium containing sucrose. Our results suggest that co-expression of compatible chaperones will be necessary for successful assembly of red algal Rubisco in plants.
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Affiliation(s)
- Myat T. Lin
- Department of Molecular Biology and GeneticsCornell UniversityIthacaNYUSA
| | - Maureen R. Hanson
- Department of Molecular Biology and GeneticsCornell UniversityIthacaNYUSA
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34
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Zhao Q, Liu C. Chloroplast Chaperonin: An Intricate Protein Folding Machine for Photosynthesis. Front Mol Biosci 2018; 4:98. [PMID: 29404339 PMCID: PMC5780408 DOI: 10.3389/fmolb.2017.00098] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 12/28/2017] [Indexed: 11/13/2022] Open
Abstract
Group I chaperonins are large cylindrical-shaped nano-machines that function as a central hub in the protein quality control system in the bacterial cytosol, mitochondria and chloroplasts. In chloroplasts, proteins newly synthesized by chloroplast ribosomes, unfolded by diverse stresses, or translocated from the cytosol run the risk of aberrant folding and aggregation. The chloroplast chaperonin system assists these proteins in folding into their native states. A widely known protein folded by chloroplast chaperonin is the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), an enzyme responsible for the fixation of inorganic CO2 into organic carbohydrates during photosynthesis. Chloroplast chaperonin was initially identified as a Rubisco-binding protein. All photosynthetic eucaryotes genomes encode multiple chaperonin genes which can be divided into α and β subtypes. Unlike the homo-oligomeric chaperonins from bacteria and mitochondria, chloroplast chaperonins are more complex and exists as intricate hetero-oligomers containing both subtypes. The Group I chaperonin requires proper interaction with a detachable lid-like co-chaperonin in the presence of ATP and Mg2+ for substrate encapsulation and conformational transition. Besides the typical Cpn10-like co-chaperonin, a unique co-chaperonin consisting of two tandem Cpn10-like domains joined head-to-tail exists in chloroplasts. Since chloroplasts were proposed as sensors to various environmental stresses, this diversified chloroplast chaperonin system has the potential to adapt to complex conditions by accommodating specific substrates or through regulation at both the transcriptional and post-translational levels. In this review, we discuss recent progress on the unique structure and function of the chloroplast chaperonin system based on model organisms Chlamydomonas reinhardtii and Arabidopsis thaliana. Knowledge of the chloroplast chaperonin system may ultimately lead to successful reconstitution of eukaryotic Rubisco in vitro.
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Affiliation(s)
- Qian Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Cuimin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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35
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Pulido P, Leister D. Novel DNAJ-related proteins in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2018; 217:480-490. [PMID: 29271039 DOI: 10.1111/nph.14827] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Classical DNAJ proteins are co-chaperones that together with HSP70s control protein homeostasis. All three classical types of DNAJ proteins (DNAJA, DNAJB and DNAJC types) possess the J-domain for interaction with HSP70. DNAJA proteins contain, in addition, both the zinc-finger motif and the C-terminal domain which are involved in substrate binding, while DNAJB retains only the latter and DNAJC comprises only the J-domain. There is increasing evidence that some of the activities of DNAJ proteins do not require the J-domain, highlighting the functional significance of the other two domains. Indeed, the so-called DNAJ-like proteins with a degenerate J-domain have been previously coined as DNAJD proteins, and also proteins containing only a DNAJ-like zinc-finger motif appear to be involved in protein homeostasis. Therefore, we propose to extend the classification of DNAJ-related proteins into three different groups. The DNAJD type comprises proteins with a J-like domain only, and has 15 members in Arabidopsis thaliana, whereas proteins of the DNAJE (33 Arabidopsis members) and DNAJF (three Arabidopsis members) types contain a DNAJA-like zinc-finger domain and DNAJA/B-like C-terminal domain, respectively. Here, we provide an overview of the entire repertoire of these proteins in A. thaliana with respect to their physiological function and possible evolutionary origin.
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Affiliation(s)
- Pablo Pulido
- Plant Molecular Biology, Department Biology I, Ludwig-Maximilians-Universität München, D-82152, Planegg-Martinsried, Germany
- Copenhagen Plant Science Centre, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Dario Leister
- Plant Molecular Biology, Department Biology I, Ludwig-Maximilians-Universität München, D-82152, Planegg-Martinsried, Germany
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36
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Affiliation(s)
- Todd O. Yeates
- University of California Los Angeles (UCLA) Department of Chemistry and Biochemistry and UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, CA, USA
| | - Nicole M. Wheatley
- University of California Los Angeles (UCLA) Department of Chemistry and Biochemistry and UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, CA, USA
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37
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Salesse C, Sharwood R, Sakamoto W, Stern D. The Rubisco Chaperone BSD2 May Regulate Chloroplast Coverage in Maize Bundle Sheath Cells. PLANT PHYSIOLOGY 2017; 175:1624-1633. [PMID: 29089394 PMCID: PMC5717744 DOI: 10.1104/pp.17.01346] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/27/2017] [Indexed: 05/04/2023]
Abstract
In maize (Zea mays), Bundle Sheath Defective2 (BSD2) plays an essential role in Rubisco biogenesis and is required for correct bundle sheath (BS) cell differentiation. Yet, BSD2 RNA and protein levels are similar in mesophyll (M) and BS chloroplasts, although Rubisco accumulates only in BS chloroplasts. This raises the possibility of additional BSD2 roles in cell development. To test this hypothesis, transgenic lines were created that overexpress and underexpress BSD2 in both BS and M cells, driven by the cell type-specific Rubisco Small Subunit (RBCS) or Phosphoenolpyruvate Carboxylase (PEPC) promoters or the ubiquitin promoter. Genetic crosses showed that each of the transgenes could complement Rubisco deficiency and seedling lethality conferred by the bsd2 mutation. This was unexpected, as RBCS-BSD2 lines lacked BSD2 in M chloroplasts and PEPC-BSD2 lines expressed half the wild-type BSD2 level in BS chloroplasts. We conclude that BSD2 does not play a vital role in M cells and that BS BSD2 is in excess of requirements for Rubisco accumulation. BSD2 levels did affect chloroplast coverage in BS cells. In PEPC-BSD2 lines, chloroplast coverage decreased 30% to 50%, whereas lines with increased BSD2 content exhibited a 25% increase. This suggests that BSD2 has an ancillary role in BS cells related to chloroplast size. Gas exchange showed decreased photosynthetic rates in PEPC-BSD2 lines despite restored Rubisco function, correlating with reduced chloroplast coverage and pointing to CO2 diffusion changes. Conversely, increased chloroplast coverage did not result in increased Rubisco abundance or photosynthetic rates. This suggests another limitation beyond chloroplast volume, most likely Rubisco biogenesis and/or turnover rates.
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Affiliation(s)
- Coralie Salesse
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
| | - Robert Sharwood
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - David Stern
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
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38
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Salesse C, Sharwood R, Sakamoto W, Stern D. The Rubisco Chaperone BSD2 May Regulate Chloroplast Coverage in Maize Bundle Sheath Cells. PLANT PHYSIOLOGY 2017. [PMID: 29089394 DOI: 10.1104/pp.17.0134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In maize (Zea mays), Bundle Sheath Defective2 (BSD2) plays an essential role in Rubisco biogenesis and is required for correct bundle sheath (BS) cell differentiation. Yet, BSD2 RNA and protein levels are similar in mesophyll (M) and BS chloroplasts, although Rubisco accumulates only in BS chloroplasts. This raises the possibility of additional BSD2 roles in cell development. To test this hypothesis, transgenic lines were created that overexpress and underexpress BSD2 in both BS and M cells, driven by the cell type-specific Rubisco Small Subunit (RBCS) or Phosphoenolpyruvate Carboxylase (PEPC) promoters or the ubiquitin promoter. Genetic crosses showed that each of the transgenes could complement Rubisco deficiency and seedling lethality conferred by the bsd2 mutation. This was unexpected, as RBCS-BSD2 lines lacked BSD2 in M chloroplasts and PEPC-BSD2 lines expressed half the wild-type BSD2 level in BS chloroplasts. We conclude that BSD2 does not play a vital role in M cells and that BS BSD2 is in excess of requirements for Rubisco accumulation. BSD2 levels did affect chloroplast coverage in BS cells. In PEPC-BSD2 lines, chloroplast coverage decreased 30% to 50%, whereas lines with increased BSD2 content exhibited a 25% increase. This suggests that BSD2 has an ancillary role in BS cells related to chloroplast size. Gas exchange showed decreased photosynthetic rates in PEPC-BSD2 lines despite restored Rubisco function, correlating with reduced chloroplast coverage and pointing to CO2 diffusion changes. Conversely, increased chloroplast coverage did not result in increased Rubisco abundance or photosynthetic rates. This suggests another limitation beyond chloroplast volume, most likely Rubisco biogenesis and/or turnover rates.
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Affiliation(s)
- Coralie Salesse
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
| | - Robert Sharwood
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - David Stern
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
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Kolesinski P, Rydzy M, Szczepaniak A. Is RAF1 protein from Synechocystis sp. PCC 6803 really needed in the cyanobacterial Rubisco assembly process? PHOTOSYNTHESIS RESEARCH 2017; 132:135-148. [PMID: 28108864 PMCID: PMC5387032 DOI: 10.1007/s11120-017-0336-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/02/2017] [Indexed: 05/29/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is responsible for carbon dioxide conversion during photosynthesis and, therefore, is the most important protein in biomass generation. Modifications of this biocatalyst toward improvements in its properties are hindered by the complicated and not yet fully understood assembly process required for the formation of active holoenzymes. An entire set of auxiliary factors, including chaperonin GroEL/GroES and assembly chaperones RbcX or Rubisco accumulation factor 1 (RAF1), is involved in the folding and subsequent assembly of Rubisco subunits. Recently, it has been shown that cyanobacterial RAF1 acts during the formation of the large Rubisco subunit (RbcL) dimer. However, both its physiological function and its necessity in the prokaryotic Rubisco formation process remain elusive. Here, we demonstrate that the Synechocystis sp. PCC 6803 strain with raf1 gene disruption shows the same growth rate as wild-type cells under standard conditions. Moreover, the Rubisco biosynthesis process seems to be unperturbed in mutant cells despite the absence of RbcL-RAF1 complexes. However, in the tested environmental conditions, sulfur starvation triggers the degradation of RbcL and subsequent proteolysis of other polypeptides in wild-type but not Δraf1 strains. Pull-down experiments also indicate that, apart from Rubisco, RAF1 co-purifies with phycocyanins. We postulate that RAF1 is not an obligatory factor in cyanobacterial Rubisco assembly, but rather participates in environmentally regulated Rubisco homeostasis.
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Affiliation(s)
- Piotr Kolesinski
- Laboratory of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland.
| | - Malgorzata Rydzy
- Laboratory of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Andrzej Szczepaniak
- Laboratory of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland
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Bracher A, Whitney SM, Hartl FU, Hayer-Hartl M. Biogenesis and Metabolic Maintenance of Rubisco. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:29-60. [PMID: 28125284 DOI: 10.1146/annurev-arplant-043015-111633] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) mediates the fixation of atmospheric CO2 in photosynthesis by catalyzing the carboxylation of the 5-carbon sugar ribulose-1,5-bisphosphate (RuBP). Rubisco is a remarkably inefficient enzyme, fixing only 2-10 CO2 molecules per second. Efforts to increase crop yields by bioengineering Rubisco remain unsuccessful, owing in part to the complex cellular machinery required for Rubisco biogenesis and metabolic maintenance. The large subunit of Rubisco requires the chaperonin system for folding, and recent studies have shown that assembly of hexadecameric Rubisco is mediated by specific assembly chaperones. Moreover, Rubisco function can be inhibited by a range of sugar-phosphate ligands, including RuBP. Metabolic repair depends on remodeling of Rubisco by the ATP-dependent Rubisco activase and hydrolysis of inhibitory sugar phosphates by specific phosphatases. Here, we review our present understanding of the structure and function of these auxiliary factors and their utilization in efforts to engineer more catalytically efficient Rubisco enzymes.
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Affiliation(s)
- Andreas Bracher
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ; , ,
| | - Spencer M Whitney
- Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia;
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ; , ,
| | - Manajit Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ; , ,
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Khan F, Chai HH, Ajmera I, Hodgman C, Mayes S, Lu C. A Transcriptomic Comparison of Two Bambara Groundnut Landraces under Dehydration Stress. Genes (Basel) 2017; 8:E121. [PMID: 28420201 PMCID: PMC5406868 DOI: 10.3390/genes8040121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 11/18/2022] Open
Abstract
The ability to grow crops under low-water conditions is a significant advantage in relation to global food security. Bambara groundnut is an underutilised crop grown by subsistence farmers in Africa and is known to survive in regions of water deficit. This study focuses on the analysis of the transcriptomic changes in two bambara groundnut landraces in response to dehydration stress. A cross-species hybridisation approach based on the Soybean Affymetrix GeneChip array has been employed. The differential gene expression analysis of a water-limited treatment, however, showed that the two landraces responded with almost completely different sets of genes. Hence, both landraces with very similar genotypes (as assessed by the hybridisation of genomic DNA onto the Soybean Affymetrix GeneChip) showed contrasting transcriptional behaviour in response to dehydration stress. In addition, both genotypes showed a high expression of dehydration-associated genes, even under water-sufficient conditions. Several gene regulators were identified as potentially important. Some are already known, such as WRKY40, but others may also be considered, namely PRR7, ATAUX2-11, CONSTANS-like 1, MYB60, AGL-83, and a Zinc-finger protein. These data provide a basis for drought trait research in the bambara groundnut, which will facilitate functional genomics studies. An analysis of this dataset has identified that both genotypes appear to be in a dehydration-ready state, even in the absence of dehydration stress, and may have adapted in different ways to achieve drought resistance. This will help in understanding the mechanisms underlying the ability of crops to produce viable yields under drought conditions. In addition, cross-species hybridisation to the soybean microarray has been shown to be informative for investigating the bambara groundnut transcriptome.
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Affiliation(s)
- Faraz Khan
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Nottingham LE12 5RD, UK.
| | - Hui Hui Chai
- Crops for the Future, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia.
| | - Ishan Ajmera
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Nottingham LE12 5RD, UK.
| | - Charlie Hodgman
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Nottingham LE12 5RD, UK.
| | - Sean Mayes
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Nottingham LE12 5RD, UK.
- Crops for the Future, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia.
| | - Chungui Lu
- School of Animal Rural and Environmental Sciences, Nottingham Trent University, Clifton Campus, Nottingham NG11 8NS, UK.
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Muñoz-Nortes T, Pérez-Pérez JM, Ponce MR, Candela H, Micol JL. The ANGULATA7 gene encodes a DnaJ-like zinc finger-domain protein involved in chloroplast function and leaf development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:870-884. [PMID: 28008672 DOI: 10.1111/tpj.13466] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
The characterization of mutants with altered leaf shape and pigmentation has previously allowed the identification of nuclear genes that encode plastid-localized proteins that perform essential functions in leaf growth and development. A large-scale screen previously allowed us to isolate ethyl methanesulfonate-induced mutants with small rosettes and pale green leaves with prominent marginal teeth, which were assigned to a phenotypic class that we dubbed Angulata. The molecular characterization of the 12 genes assigned to this phenotypic class should help us to advance our understanding of the still poorly understood relationship between chloroplast biogenesis and leaf morphogenesis. In this article, we report the phenotypic and molecular characterization of the angulata7-1 (anu7-1) mutant of Arabidopsis thaliana, which we found to be a hypomorphic allele of the EMB2737 gene, which was previously known only for its embryonic-lethal mutations. ANU7 encodes a plant-specific protein that contains a domain similar to the central cysteine-rich domain of DnaJ proteins. The observed genetic interaction of anu7-1 with a loss-of-function allele of GENOMES UNCOUPLED1 suggests that the anu7-1 mutation triggers a retrograde signal that leads to changes in the expression of many genes that normally function in the chloroplasts. Many such genes are expressed at higher levels in anu7-1 rosettes, with a significant overrepresentation of those required for the expression of plastid genome genes. Like in other mutants with altered expression of plastid-encoded genes, we found that anu7-1 exhibits defects in the arrangement of thylakoidal membranes, which appear locally unappressed.
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Affiliation(s)
- Tamara Muñoz-Nortes
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, 03202, Spain
| | - José Manuel Pérez-Pérez
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, 03202, Spain
| | - María Rosa Ponce
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, 03202, Spain
| | - Héctor Candela
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, 03202, Spain
| | - José Luis Micol
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, 03202, Spain
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Reeves G, Grangé-Guermente MJ, Hibberd JM. Regulatory gateways for cell-specific gene expression in C4 leaves with Kranz anatomy. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:107-116. [PMID: 27940469 DOI: 10.1093/jxb/erw438] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
C4 photosynthesis is a carbon-concentrating mechanism that increases delivery of carbon dioxide to RuBisCO and as a consequence reduces photorespiration. The C4 pathway is therefore beneficial in environments that promote high photorespiration. This pathway has evolved many times, and involves restricting gene expression to either mesophyll or bundle sheath cells. Here we review the regulatory mechanisms that control cell-preferential expression of genes in the C4 cycle. From this analysis, it is clear that the C4 pathway has a complex regulatory framework, with control operating at epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels. Some genes of the C4 pathway are regulated at multiple levels, and we propose that this ensures robust expression in each cell type. Accumulating evidence suggests that multiple genes of the C4 pathway may share the same regulatory mechanism. The control systems for C4 photosynthesis gene expression appear to operate in C3 plants, and so it appears that pre-existing mechanisms form the basis of C4 photosynthesis gene expression.
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Affiliation(s)
- Gregory Reeves
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | | | - Julian M Hibberd
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
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Sharwood RE. Engineering chloroplasts to improve Rubisco catalysis: prospects for translating improvements into food and fiber crops. THE NEW PHYTOLOGIST 2017; 213:494-510. [PMID: 27935049 DOI: 10.1111/nph.14351] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/10/2016] [Indexed: 05/19/2023]
Abstract
494 I. 495 II. 496 III. 496 IV. 499 V. 499 VI. 501 VII. 501 VIII. 502 IX. 505 X. 506 507 References 507 SUMMARY: The uncertainty of future climate change is placing pressure on cropping systems to continue to provide stable increases in productive yields. To mitigate future climates and the increasing threats against global food security, new solutions to manipulate photosynthesis are required. This review explores the current efforts available to improve carbon assimilation within plant chloroplasts by engineering Rubisco, which catalyzes the rate-limiting step of CO2 fixation. Fixation of CO2 and subsequent cycling of 3-phosphoglycerate through the Calvin cycle provides the necessary carbohydrate building blocks for maintaining plant growth and yield, but has to compete with Rubisco oxygenation, which results in photorespiration that is energetically wasteful for plants. Engineering improvements in Rubisco is a complex challenge and requires an understanding of chloroplast gene regulatory pathways, and the intricate nature of Rubisco catalysis and biogenesis, to transplant more efficient forms of Rubisco into crops. In recent times, major advances in Rubisco engineering have been achieved through improvement of our knowledge of Rubisco synthesis and assembly, and identifying amino acid catalytic switches in the L-subunit responsible for improvements in catalysis. Improving the capacity of CO2 fixation in crops such as rice will require further advances in chloroplast bioengineering and Rubisco biogenesis.
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Affiliation(s)
- Robert E Sharwood
- ARC Center of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
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Sharwood RE, Ghannoum O, Whitney SM. Prospects for improving CO2 fixation in C3-crops through understanding C4-Rubisco biogenesis and catalytic diversity. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:135-42. [PMID: 27131319 DOI: 10.1016/j.pbi.2016.04.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 05/09/2023]
Abstract
By operating a CO2 concentrating mechanism, C4-photosynthesis offers highly successful solutions to remedy the inefficiency of the CO2-fixing enzyme Rubisco. C4-plant Rubisco has characteristically evolved faster carboxylation rates with low CO2 affinity. Owing to high CO2 concentrations in bundle sheath chloroplasts, faster Rubisco enhances resource use efficiency in C4 plants by reducing the energy and carbon costs associated with photorespiration and lowering the nitrogen investment in Rubisco. Here, we show that C4-Rubisco from some NADP-ME species, such as maize, are also of potential benefit to C3-photosynthesis under current and future atmospheric CO2 pressures. Realizing this bioengineering endeavour necessitates improved understanding of the biogenesis requirements and catalytic variability of C4-Rubisco, as well as the development of transformation capabilities to engineer Rubisco in a wider variety of food and fibre crops.
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Affiliation(s)
- Robert E Sharwood
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, ACT 2601, Australia.
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Spencer M Whitney
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, ACT 2601, Australia
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Wang YW, Chen SM, Wang WJ, Huang XQ, Zhou CF, Zhuang Z, Lu S. The DnaJ-Like Zinc Finger Domain Protein PSA2 Affects Light Acclimation and Chloroplast Development in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2016; 7:360. [PMID: 27047527 PMCID: PMC4806229 DOI: 10.3389/fpls.2016.00360] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/08/2016] [Indexed: 05/20/2023]
Abstract
The biosynthesis of chlorophylls and carotenoids and the assembly of thylakoid membranes are critical for the photoautotrophic growth of plants. Different factors are involved in these two processes. In recent years, members of the DnaJ-like zinc finger domain proteins have been found to take part in the biogenesis and/or the maintenance of plastids. One member of this family of proteins, PSA2, was recently found to localize to the thylakoid lumen and regulate the accumulation of photosystem I. In this study, we report that the silencing of PSA2 in Arabidopsis thaliana resulted in variegated leaves and retarded growth. Although both chlorophylls and total carotenoids decreased in the psa2 mutant, violaxanthin, and zeaxanthin accumulated in the mutant seedlings grown under growth condition. Lower levels of non-photochemical quenching and electron transport rate were also found in the psa2 mutant seedlings under growth condition compared with those of the wild-type plants, indicating an impaired capability to acclimate to normal light irradiance when PSA2 was silenced. Moreover, we also observed an abnormal assembly of grana thylakoids and poorly developed stroma thylakoids in psa2 chloroplasts. Taken together, our results demonstrate that PSA2 is a member of the DnaJ-like zinc finger domain protein family that affects light acclimation and chloroplast development.
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Affiliation(s)
| | | | | | | | | | | | - Shan Lu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing UniversityNanjing, China
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47
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Hauser T, Popilka L, Hartl FU, Hayer-Hartl M. Role of auxiliary proteins in Rubisco biogenesis and function. NATURE PLANTS 2015; 1:15065. [PMID: 27250005 DOI: 10.1038/nplants.2015.65] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 04/20/2015] [Indexed: 05/05/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the conversion of atmospheric CO2 into organic compounds during photosynthesis. Despite its pivotal role in plant metabolism, Rubisco is an inefficient enzyme and has therefore been a key target in bioengineering efforts to improve crop yields. Much has been learnt about the complex cellular machinery involved in Rubisco assembly and metabolic repair over recent years. The simple form of Rubisco found in certain bacteria and dinoflagellates comprises two large subunits, and generally requires the chaperonin system for folding. However, the evolution of hexadecameric Rubisco, which comprises eight large and eight small subunits, from its dimeric precursor has rendered Rubisco in most plants, algae, cyanobacteria and proteobacteria dependent on an array of additional factors. These auxiliary factors include several chaperones for assembly as well as ATPases of the AAA+ family for functional maintenance. An integrated view of the pathways underlying Rubisco biogenesis and repair will pave the way for efforts to improve the enzyme with the goal of increasing crop yields.
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Affiliation(s)
- Thomas Hauser
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Leonhard Popilka
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Manajit Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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48
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Wang G, Kong F, Zhang S, Meng X, Wang Y, Meng Q. A tomato chloroplast-targeted DnaJ protein protects Rubisco activity under heat stress. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:3027-40. [PMID: 25801077 DOI: 10.1093/jxb/erv102] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Photosynthesis is one of the biological processes most sensitive to heat stress in plants. Carbon assimilation, which depends on ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), is one of the major sites sensitive to heat stress in photosynthesis. In this study, the roles of a tomato (Solanum lycopersicum) chloroplast-targeted DnaJ protein (SlCDJ2) in resisting heat using sense and antisense transgenic tomatoes were examined. SlCDJ2 was found to be uniformly distributed in the thylakoids and stroma of the chloroplasts. Under heat stress, sense plants exhibited higher chlorophyll contents and fresh weights, and lower accumulation of reactive oxygen species (ROS) and membrane damage. Moreover, Rubisco activity, Rubisco large subunit (RbcL) content, and CO2 assimilation capacity were all higher in sense plants and lower in antisense plants compared with wild-type plants. Thus, SlCDJ2 contributes to maintenance of CO2 assimilation capacity mainly by protecting Rubisco activity under heat stress. SlCDJ2 probably achieves this by keeping the levels of proteolytic enzymes low, which prevents accelerated degradation of Rubisco under heat stress. Furthermore, a chloroplast heat-shock protein 70 was identified as a binding partner of SlCDJ2 in yeast two-hybrid assays. Taken together, these findings establish a role for SlCDJ2 in maintaining Rubisco activity in plants under heat stress.
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Affiliation(s)
- Guodong Wang
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Fanying Kong
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Song Zhang
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Xia Meng
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Yong Wang
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Qingwei Meng
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
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Whitney SM, Birch R, Kelso C, Beck JL, Kapralov MV. Improving recombinant Rubisco biogenesis, plant photosynthesis and growth by coexpressing its ancillary RAF1 chaperone. Proc Natl Acad Sci U S A 2015; 112:3564-9. [PMID: 25733857 PMCID: PMC4371954 DOI: 10.1073/pnas.1420536112] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Enabling improvements to crop yield and resource use by enhancing the catalysis of the photosynthetic CO2-fixing enzyme Rubisco has been a longstanding challenge. Efforts toward realization of this goal have been greatly assisted by advances in understanding the complexities of Rubisco's biogenesis in plastids and the development of tailored chloroplast transformation tools. Here we generate transplastomic tobacco genotypes expressing Arabidopsis Rubisco large subunits (AtL), both on their own (producing tob(AtL) plants) and with a cognate Rubisco accumulation factor 1 (AtRAF1) chaperone (producing tob(AtL-R1) plants) that has undergone parallel functional coevolution with AtL. We show AtRAF1 assembles as a dimer and is produced in tob(AtL-R1) and Arabidopsis leaves at 10-15 nmol AtRAF1 monomers per square meter. Consistent with a postchaperonin large (L)-subunit assembly role, the AtRAF1 facilitated two to threefold improvements in the amount and biogenesis rate of hybrid L8(A)S8(t) Rubisco [comprising AtL and tobacco small (S) subunits] in tob(AtL-R1) leaves compared with tob(AtL), despite >threefold lower steady-state Rubisco mRNA levels in tob(AtL-R1). Accompanying twofold increases in photosynthetic CO2-assimilation rate and plant growth were measured for tob(AtL-R1) lines. These findings highlight the importance of ancillary protein complementarity during Rubisco biogenesis in plastids, the possible constraints this has imposed on Rubisco adaptive evolution, and the likely need for such interaction specificity to be considered when optimizing recombinant Rubisco bioengineering in plants.
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Affiliation(s)
- Spencer M Whitney
- Research School of Biology, Australian National University, Acton, ACT 2601, Australia; and
| | - Rosemary Birch
- Research School of Biology, Australian National University, Acton, ACT 2601, Australia; and
| | - Celine Kelso
- School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Jennifer L Beck
- School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Maxim V Kapralov
- Research School of Biology, Australian National University, Acton, ACT 2601, Australia; and
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50
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Belcher S, Williams-Carrier R, Stiffler N, Barkan A. Large-scale genetic analysis of chloroplast biogenesis in maize. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1004-16. [PMID: 25725436 DOI: 10.1016/j.bbabio.2015.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/16/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND Chloroplast biogenesis involves a collaboration between several thousand nuclear genes and ~100 genes in the chloroplast. Many of the nuclear genes are of cyanobacterial ancestry and continue to perform their ancestral function. However, many others evolved subsequently and comprise a diverse set of proteins found specifically in photosynthetic eucaryotes. Genetic approaches have been key to the discovery of nuclear genes that participate in chloroplast biogenesis, especially those lacking close homologs outside the plant kingdom. SCOPE OF REVIEW This article summarizes contributions from a genetic resource in maize, the Photosynthetic Mutant Library (PML). The PML collection consists of ~2000 non-photosynthetic mutants induced by Mu transposons. We include a summary of mutant phenotypes for 20 previously unstudied maize genes, including genes encoding chloroplast ribosomal proteins, a PPR protein, tRNA synthetases, proteins involved in plastid transcription, a putative ribosome assembly factor, a chaperonin 60 isoform, and a NifU-domain protein required for Photosystem I biogenesis. MAJOR CONCLUSIONS Insertions in 94 maize genes have been linked thus far to visible and molecular phenotypes with the PML collection. The spectrum of chloroplast biogenesis genes that have been genetically characterized in maize is discussed in the context of related efforts in other organisms. This comparison shows how distinct organismal attributes facilitate the discovery of different gene classes, and reveals examples of functional divergence between monocot and dicot plants. GENERAL SIGNIFICANCE These findings elucidate the biology of an organelle whose activities are fundamental to agriculture and the biosphere. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Susan Belcher
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | | | - Nicholas Stiffler
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.
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