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Yogadasan N, Doxey AC, Chuong SDX. A Machine Learning Framework Identifies Plastid-Encoded Proteins Harboring C3 and C4 Distinguishing Sequence Information. Genome Biol Evol 2023; 15:evad129. [PMID: 37462292 PMCID: PMC10368328 DOI: 10.1093/gbe/evad129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2023] [Indexed: 07/27/2023] Open
Abstract
C4 photosynthesis is known to have at least 61 independent origins across plant lineages making it one of the most notable examples of convergent evolution. Of the >60 independent origins, a predicted 22-24 origins, encompassing greater than 50% of all known C4 species, exist within the Panicoideae, Arundinoideae, Chloridoideae, Micrairoideae, Aristidoideae, and Danthonioideae (PACMAD) clade of the Poaceae family. This clade is therefore primed with species ideal for the study of genomic changes associated with the acquisition of the C4 photosynthetic trait. In this study, we take advantage of the growing availability of sequenced plastid genomes and employ a machine learning (ML) approach to screen for plastid genes harboring C3 and C4 distinguishing information in PACMAD species. We demonstrate that certain plastid-encoded protein sequences possess distinguishing and informative sequence information that allows them to train accurate ML C3/C4 classification models. Our RbcL-trained model, for example, informs a C3/C4 classifier with greater than 99% accuracy. Accurate prediction of photosynthetic type from individual sequences suggests biologically relevant, and potentially differing roles of these sequence products in C3 versus C4 metabolism. With this ML framework, we have identified several key sequences and sites that are most predictive of C3/C4 status, including RbcL, subunits of the NAD(P)H dehydrogenase complex, and specific residues within, further highlighting their potential significance in the evolution and/or maintenance of C4 photosynthetic machinery. This general approach can be applied to uncover intricate associations between other similar genotype-phenotype relationships.
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Affiliation(s)
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Simon D X Chuong
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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Rangan P, Wankhede DP, Subramani R, Chinnusamy V, Malik SK, Baig MJ, Singh K, Henry R. Evolution of an intermediate C 4 photosynthesis in the non-foliar tissues of the Poaceae. PHOTOSYNTHESIS RESEARCH 2022; 153:125-134. [PMID: 35648247 DOI: 10.1007/s11120-022-00926-7] [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: 02/08/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Carbon concentrating mechanisms (CCMs) in plants are abaptive features that have evolved to sustain plant growth in unfavorable environments, especially at low atmospheric carbon levels and high temperatures. Uptake of CO2 and its storage in the aerenchyma tissues of Lycopsids and diurnal acidity fluctuation in aquatic plants during the Palaeozoic era (ca. 300 Ma.) would represent the earliest evolution of a CCM. The CCM parts of the dark reactions of photosynthesis have evolved many times, while the light reactions are conserved across plant lineages. A C4 type CCM, leaf C4 photosynthesis is evolved in the PACMAD clade of the Poaceae family. The evolution of C4 photosynthesis from C3 photosynthesis was an abaptation. Photosynthesis in reproductive tissues of sorghum and maize (PACMAD clade) has been shown to be of a weaker C4 type (high CO2 compensation point, low carbon isotope discrimination, and lack of Rubisco compartmentalization, when compared to the normal C4 types) than that in the leaves (normal C4 type). However, this does not fit well with the character polarity concept from an evolutionary perspective. In a recent model proposed for CCM evolution, the development of a rudimentary CCM prior to the evolution of a more efficient CCM (features contrasting to a weaker C4 type, leading to greater biomass production rate) has been suggested. An intermediate crassulacean acid metabolism (CAM) type of CCM (rudimentary) was reported in the genera, Brassia, Coryanthes, Eriopsis, Peristeria, of the orchids (well-known group of plants that display the CAM pathway). Similarly, we propose here the evolution of a rudimentary CCM (C4-like type pathway) in the non-foliar tissues of the Poaceae, prior to the evolution of the C4 pathway as identified in the leaves of the C4 species of the PACMAD clade.
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Affiliation(s)
- Parimalan Rangan
- ICAR-National Bureau of Plant Genetic Resources, PUSA Campus, New Delhi, 110012, India.
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD, 4072, Australia.
| | | | - Rajkumar Subramani
- ICAR-National Bureau of Plant Genetic Resources, PUSA Campus, New Delhi, 110012, India
| | | | - Surendra K Malik
- ICAR-National Bureau of Plant Genetic Resources, PUSA Campus, New Delhi, 110012, India
| | | | - Kuldeep Singh
- ICAR-National Bureau of Plant Genetic Resources, PUSA Campus, New Delhi, 110012, India
| | - Robert Henry
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD, 4072, Australia
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3
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Sharwood RE, Quick WP, Sargent D, Estavillo GM, Silva-Perez V, Furbank RT. Mining for allelic gold: finding genetic variation in photosynthetic traits in crops and wild relatives. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3085-3108. [PMID: 35274686 DOI: 10.1093/jxb/erac081] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Improvement of photosynthetic traits in crops to increase yield potential and crop resilience has recently become a major breeding target. Synthetic biology and genetic technologies offer unparalleled opportunities to create new genetics for photosynthetic traits driven by existing fundamental knowledge. However, large 'gene bank' collections of germplasm comprising historical collections of crop species and their relatives offer a wealth of opportunities to find novel allelic variation in the key steps of photosynthesis, to identify new mechanisms and to accelerate genetic progress in crop breeding programmes. Here we explore the available genetic resources in food and fibre crops, strategies to selectively target allelic variation in genes underpinning key photosynthetic processes, and deployment of this variation via gene editing in modern elite material.
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Affiliation(s)
- Robert E Sharwood
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - W Paul Quick
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, Australia
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Demi Sargent
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | | | | | - Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, Australia
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Casola C, Li J. Beyond RuBisCO: convergent molecular evolution of multiple chloroplast genes in C 4 plants. PeerJ 2022; 10:e12791. [PMID: 35127287 PMCID: PMC8801178 DOI: 10.7717/peerj.12791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/22/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The recurrent evolution of the C4 photosynthetic pathway in angiosperms represents one of the most extraordinary examples of convergent evolution of a complex trait. Comparative genomic analyses have unveiled some of the molecular changes associated with the C4 pathway. For instance, several key enzymes involved in the transition from C3 to C4 photosynthesis have been found to share convergent amino acid replacements along C4 lineages. However, the extent of convergent replacements potentially associated with the emergence of C4 plants remains to be fully assessed. Here, we conducted an organelle-wide analysis to determine if convergent evolution occurred in multiple chloroplast proteins beside the well-known case of the large RuBisCO subunit encoded by the chloroplast gene rbcL. METHODS Our study was based on the comparative analysis of 43 C4 and 21 C3 grass species belonging to the PACMAD clade, a focal taxonomic group in many investigations of C4 evolution. We first used protein sequences of 67 orthologous chloroplast genes to build an accurate phylogeny of these species. Then, we inferred amino acid replacements along 13 C4 lineages and 9 C3 lineages using reconstructed protein sequences of their reference branches, corresponding to the branches containing the most recent common ancestors of C4-only clades and C3-only clades. Pairwise comparisons between reference branches allowed us to identify both convergent and non-convergent amino acid replacements between C4:C4, C3:C3 and C3:C4 lineages. RESULTS The reconstructed phylogenetic tree of 64 PACMAD grasses was characterized by strong supports in all nodes used for analyses of convergence. We identified 217 convergent replacements and 201 non-convergent replacements in 45/67 chloroplast proteins in both C4 and C3 reference branches. C4:C4 branches showed higher levels of convergent replacements than C3:C3 and C3:C4 branches. Furthermore, we found that more proteins shared unique convergent replacements in C4 lineages, with both RbcL and RpoC1 (the RNA polymerase beta' subunit 1) showing a significantly higher convergent/non-convergent replacements ratio in C4 branches. Notably, more C4:C4 reference branches showed higher numbers of convergent vs. non-convergent replacements than C3:C3 and C3:C4 branches. Our results suggest that, in the PACMAD clade, C4 grasses experienced higher levels of molecular convergence than C3 species across multiple chloroplast genes. These findings have important implications for our understanding of the evolution of the C4 photosynthesis pathway.
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Affiliation(s)
- Claudio Casola
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, United States of America
- Interdisciplinary Graduate Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX, United States of America
| | - Jingjia Li
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, United States of America
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Chotewutmontri P, Barkan A. Ribosome profiling elucidates differential gene expression in bundle sheath and mesophyll cells in maize. PLANT PHYSIOLOGY 2021; 187:59-72. [PMID: 34618144 PMCID: PMC8418429 DOI: 10.1093/plphys/kiab272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/10/2021] [Indexed: 05/20/2023]
Abstract
The efficiencies offered by C4 photosynthesis have motivated efforts to understand its biochemical, genetic, and developmental basis. Reactions underlying C4 traits in most C4 plants are partitioned between two cell types, bundle sheath (BS), and mesophyll (M) cells. RNA-seq has been used to catalog differential gene expression in BS and M cells in maize (Zea mays) and several other C4 species. However, the contribution of translational control to maintaining the distinct proteomes of BS and M cells has not been addressed. In this study, we used ribosome profiling and RNA-seq to describe translatomes, translational efficiencies, and microRNA abundance in BS- and M-enriched fractions of maize seedling leaves. A conservative interpretation of our data revealed 182 genes exhibiting cell type-dependent differences in translational efficiency, 31 of which encode proteins with core roles in C4 photosynthesis. Our results suggest that non-AUG start codons are used preferentially in upstream open reading frames of BS cells, revealed mRNA sequence motifs that correlate with cell type-dependent translation, and identified potential translational regulators that are differentially expressed. In addition, our data expand the set of genes known to be differentially expressed in BS and M cells, including genes encoding transcription factors and microRNAs. These data add to the resources for understanding the evolutionary and developmental basis of C4 photosynthesis and for its engineering into C3 crops.
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Affiliation(s)
- Prakitchai Chotewutmontri
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 USA
- Author for communication:
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 USA
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Kuhnert F, Schlüter U, Linka N, Eisenhut M. Transport Proteins Enabling Plant Photorespiratory Metabolism. PLANTS 2021; 10:plants10050880. [PMID: 33925393 PMCID: PMC8146403 DOI: 10.3390/plants10050880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 01/21/2023]
Abstract
Photorespiration (PR) is a metabolic repair pathway that acts in oxygenic photosynthetic organisms to degrade a toxic product of oxygen fixation generated by the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase. Within the metabolic pathway, energy is consumed and carbon dioxide released. Consequently, PR is seen as a wasteful process making it a promising target for engineering to enhance plant productivity. Transport and channel proteins connect the organelles accomplishing the PR pathway-chloroplast, peroxisome, and mitochondrion-and thus enable efficient flux of PR metabolites. Although the pathway and the enzymes catalyzing the biochemical reactions have been the focus of research for the last several decades, the knowledge about transport proteins involved in PR is still limited. This review presents a timely state of knowledge with regard to metabolite channeling in PR and the participating proteins. The significance of transporters for implementation of synthetic bypasses to PR is highlighted. As an excursion, the physiological contribution of transport proteins that are involved in C4 metabolism is discussed.
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Hunt HV, Przelomska NAS, Campana MG, Cockram J, Bligh HFJ, Kneale CJ, Romanova OI, Malinovskaya EV, Jones MK. Population genomic structure of Eurasian and African foxtail millet landrace accessions inferred from genotyping-by-sequencing. THE PLANT GENOME 2021; 14:e20081. [PMID: 33543599 PMCID: PMC8638668 DOI: 10.1002/tpg2.20081] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/15/2020] [Indexed: 05/11/2023]
Abstract
Foxtail millet [Setaria italica (L.) P. Beauv.] is the second most important millet species globally and is adapted to cultivation in diverse environments. Like its wild progenitor, green foxtail [S. viridis (L.) P. Beauv.], it is a model species for C4 photosynthetic pathways and stress tolerance genes in related bioenergy crops. We addressed questions regarding the evolution and spread of foxtail millet through a population genomic study of landraces from across its cultivated range in Europe, Asia, and Africa. We sought to determine population genomic structure and the relationship of domesticated lineages relative to green foxtail. Further, we aimed to identify genes involved in environmental stress tolerance that have undergone differential selection between geographical and genetic groups. Foxtail millet landrace accessions (n = 328) and green foxtail accessions (n = 12) were sequenced by genotyping-by-sequencing (GBS). After filtering, 5,677 single nucleotide polymorphisms (SNPs) were retained for the combined foxtail millet-green foxtail dataset and 5,020 for the foxtail millet dataset. We extended geographic coverage of green foxtail by including previously published GBS sequence tags, yielding a 4,515-SNP dataset for phylogenetic reconstruction. All foxtail millet samples were monophyletic relative to green foxtail, suggesting a single origin of foxtail millet, although no group of foxtail millet was clearly the most ancestral. Four genetic clusters were found within foxtail millet, each with a distinctive geographical distribution. These results, together with archaeobotanical evidence, suggest plausible routes of spread of foxtail millet. Selection scans identified nine candidate genes potentially involved in environmental adaptations, particularly to novel climates encountered, as domesticated foxtail millet spread to new altitudes and latitudes.
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Affiliation(s)
- Harriet V. Hunt
- McDonald Institute for Archaeological ResearchUniversity of CambridgeDowning StreetCambridgeCB2 3ERUK
| | - Natalia A. S. Przelomska
- Comparative Plant and Fungal BiologyRoyal Botanic GardensKewRichmondTW9 3AEUK
- Department of AnthropologyNational Museum of Natural HistorySmithsonian InstitutionWashingtonDC20560USA
- Center for Conservation GenomicsSmithsonian's National Zoo and Conservation Biology InstituteSmithsonian InstitutionWashingtonDC20008USA
- Department of ArchaeologyUniversity of CambridgeDowning StreetCambridgeCB2 3DZUK
| | - Michael G. Campana
- Center for Conservation GenomicsSmithsonian's National Zoo and Conservation Biology InstituteSmithsonian InstitutionWashingtonDC20008USA
| | - James Cockram
- The John Bingham LaboratoryNIAB93 Lawrence Weaver RoadCambridgeCB3 0LEUK
| | | | - Catherine J. Kneale
- McDonald Institute for Archaeological ResearchUniversity of CambridgeDowning StreetCambridgeCB2 3ERUK
| | - Olga I. Romanova
- N.I. Vavilov Institute of Plant Genetic Resources (VIR)St. Petersburg190000Russia
| | | | - Martin K. Jones
- Department of ArchaeologyUniversity of CambridgeDowning StreetCambridgeCB2 3DZUK
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Weissmann S, Huang P, Wiechert MA, Furuyama K, Brutnell TP, Taniguchi M, Schnable JC, Mockler TC. DCT4-A New Member of the Dicarboxylate Transporter Family in C4 Grasses. Genome Biol Evol 2021; 13:6126432. [PMID: 33587128 PMCID: PMC7883667 DOI: 10.1093/gbe/evaa251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2020] [Indexed: 11/15/2022] Open
Abstract
Malate transport shuttles atmospheric carbon into the Calvin–Benson cycle during NADP-ME C4 photosynthesis. Previous characterizations of several plant dicarboxylate transporters (DCT) showed that they efficiently exchange malate across membranes. Here, we identify and characterize a previously unknown member of the DCT family, DCT4, in Sorghum bicolor. We show that SbDCT4 exchanges malate across membranes and its expression pattern is consistent with a role in malate transport during C4 photosynthesis. SbDCT4 is not syntenic to the characterized photosynthetic gene ZmDCT2, and an ortholog is not detectable in the maize reference genome. We found that the expression patterns of DCT family genes in the leaves of Zea mays, and S. bicolor varied by cell type. Our results suggest that subfunctionalization, of members of the DCT family, for the transport of malate into the bundle sheath plastids, occurred during the process of independent recurrent evolution of C4 photosynthesis in grasses of the PACMAD clade. We also show that this subfunctionalization is lineage independent. Our results challenge the dogma that key C4 genes must be orthologues of one another among C4 species, and shed new light on the evolution of C4 photosynthesis.
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Affiliation(s)
- Sarit Weissmann
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - Pu Huang
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | | | - Koki Furuyama
- Graduate School of Bioagricultural Sciences, Nagoya University, Aichi, Japan
| | - Thomas P Brutnell
- Chinese Academy of Agricultural Sciences, Biotechnology Research Institute, Beijing, China
| | - Mitsutaka Taniguchi
- Graduate School of Bioagricultural Sciences, Nagoya University, Aichi, Japan
| | - James C Schnable
- Computational Sciences Initiative, Center for Plant Science Innovation, Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Nebraska, USA
| | - Todd C Mockler
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
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Bianconi ME, Hackel J, Vorontsova MS, Alberti A, Arthan W, Burke SV, Duvall MR, Kellogg EA, Lavergne S, McKain MR, Meunier A, Osborne CP, Traiperm P, Christin PA, Besnard G. Continued Adaptation of C4 Photosynthesis After an Initial Burst of Changes in the Andropogoneae Grasses. Syst Biol 2020; 69:445-461. [PMID: 31589325 PMCID: PMC7672695 DOI: 10.1093/sysbio/syz066] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/18/2019] [Accepted: 09/26/2019] [Indexed: 11/29/2022] Open
Abstract
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}{}$_{4}$\end{document} photosynthesis is a complex trait that sustains fast growth and high productivity in tropical and subtropical conditions and evolved repeatedly in flowering plants. One of the major C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} lineages is Andropogoneae, a group of \documentclass[12pt]{minimal}
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}{}$\sim $\end{document}1200 grass species that includes some of the world’s most important crops and species dominating tropical and some temperate grasslands. Previous efforts to understand C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} evolution in the group have compared a few model C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} plants to distantly related C\documentclass[12pt]{minimal}
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}{}$_{3}$\end{document} species so that changes directly responsible for the transition to C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} could not be distinguished from those that preceded or followed it. In this study, we analyze the genomes of 66 grass species, capturing the earliest diversification within Andropogoneae as well as their C\documentclass[12pt]{minimal}
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}{}$_{3}$\end{document} relatives. Phylogenomics combined with molecular dating and analyses of protein evolution show that many changes linked to the evolution of C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} photosynthesis in Andropogoneae happened in the Early Miocene, between 21 and 18 Ma, after the split from its C\documentclass[12pt]{minimal}
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}{}$_{3}$\end{document} sister lineage, and before the diversification of the group. This initial burst of changes was followed by an extended period of modifications to leaf anatomy and biochemistry during the diversification of Andropogoneae, so that a single C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} origin gave birth to a diversity of C\documentclass[12pt]{minimal}
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}{}$_{4}$\end{document} phenotypes during 18 million years of speciation events and migration across geographic and ecological spaces. Our comprehensive approach and broad sampling of the diversity in the group reveals that one key transition can lead to a plethora of phenotypes following sustained adaptation of the ancestral state. [Adaptive evolution; complex traits; herbarium genomics; Jansenelleae; leaf anatomy; Poaceae; phylogenomics.]
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Affiliation(s)
- Matheus E Bianconi
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Jan Hackel
- Laboratoire Evolution & Diversité Biologique (EDB, UMR 5174), CNRS/IRD/Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - Maria S Vorontsova
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - Adriana Alberti
- CEA - Institut de Biologie Francois-Jacob, Genoscope, 2 Rue Gaston Cremieux 91057 Evry Cedex, France
| | - Watchara Arthan
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK
| | - Sean V Burke
- Department of Biological Sciences, Plant Molecular and Bioinformatics Center, Northern Illinois University, 1425 W. Lincoln Hwy, DeKalb, IL 60115-2861, USA
| | - Melvin R Duvall
- Department of Biological Sciences, Plant Molecular and Bioinformatics Center, Northern Illinois University, 1425 W. Lincoln Hwy, DeKalb, IL 60115-2861, USA
| | - Elizabeth A Kellogg
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MI 63132, USA
| | - Sébastien Lavergne
- Laboratoire d’Ecologie Alpine, CNRS – Université Grenoble Alpes, UMR 5553, Grenoble, France
| | - Michael R McKain
- Department of Biological Sciences, The University of Alabama, 500 Hackberry Lane, Tuscaloosa, AL 35487, USA
| | - Alexandre Meunier
- Laboratoire Evolution & Diversité Biologique (EDB, UMR 5174), CNRS/IRD/Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Paweena Traiperm
- Department of Plant Science, Faculty of Science, Mahidol University, King Rama VI Road, Bangkok 10400, Thailand
| | - Pascal-Antoine Christin
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Guillaume Besnard
- Laboratoire Evolution & Diversité Biologique (EDB, UMR 5174), CNRS/IRD/Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France
- Correspondence to be sent to: Laboratoire Evolution & Diversité Biologique (EDB, UMR 5174), CNRS/IRD/Université Toulouse III, 118 route de Narbonne, 31062 Toulouse, France; E-mail:
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AuBuchon-Elder T, Coneva V, Goad DM, Jenkins LM, Yu Y, Allen DK, Kellogg EA. Sterile Spikelets Contribute to Yield in Sorghum and Related Grasses. THE PLANT CELL 2020; 32:3500-3518. [PMID: 32873633 PMCID: PMC7610286 DOI: 10.1105/tpc.20.00424] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/05/2020] [Accepted: 08/26/2020] [Indexed: 05/14/2023]
Abstract
Sorghum (Sorghum bicolor) and its relatives in the grass tribe Andropogoneae bear their flowers in pairs of spikelets in which one spikelet (seed-bearing or sessile spikelet [SS]) of the pair produces a seed and the other is sterile or male (staminate). This division of function does not occur in other major cereals such as wheat (Triticum aestivum) or rice (Oryza sativa). Additionally, one bract of the SS spikelet often produces a long extension, the awn, that is in the same position as, but independently derived from, that of wheat and rice. The function of the sterile spikelet is unknown and that of the awn has not been tested in Andropogoneae. We used radioactive and stable isotopes of carbon, RNA sequencing of metabolically important enzymes, and immunolocalization of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) to show that the sterile spikelet assimilates carbon, which is translocated to the largely heterotrophic SS. The awn shows no evidence of photosynthesis. These results apply to distantly related species of Andropogoneae. Removal of sterile spikelets in sorghum significantly decreases seed weight (yield) by ∼9%. Thus, the sterile spikelet, but not the awn, affects yield in the cultivated species and fitness in the wild species.
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Affiliation(s)
| | | | - David M Goad
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Lauren M Jenkins
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- U.S. Department of Agriculture-Agricultural Research Service, St. Louis, Missouri 63132
| | - Yunqing Yu
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- U.S. Department of Agriculture-Agricultural Research Service, St. Louis, Missouri 63132
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11
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Tao Y, George-Jaeggli B, Bouteillé-Pallas M, Tai S, Cruickshank A, Jordan D, Mace E. Genetic Diversity of C 4 Photosynthesis Pathway Genes in Sorghum bicolor (L.). Genes (Basel) 2020; 11:E806. [PMID: 32708598 PMCID: PMC7397294 DOI: 10.3390/genes11070806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 01/28/2023] Open
Abstract
C4 photosynthesis has evolved in over 60 different plant taxa and is an excellent example of convergent evolution. Plants using the C4 photosynthetic pathway have an efficiency advantage, particularly in hot and dry environments. They account for 23% of global primary production and include some of our most productive cereals. While previous genetic studies comparing phylogenetically related C3 and C4 species have elucidated the genetic diversity underpinning the C4 photosynthetic pathway, no previous studies have described the genetic diversity of the genes involved in this pathway within a C4 crop species. Enhanced understanding of the allelic diversity and selection signatures of genes in this pathway may present opportunities to improve photosynthetic efficiency, and ultimately yield, by exploiting natural variation. Here, we present the first genetic diversity survey of 8 known C4 gene families in an important C4 crop, Sorghum bicolor (L.) Moench, using sequence data of 48 genotypes covering wild and domesticated sorghum accessions. Average nucleotide diversity of C4 gene families varied more than 20-fold from the NADP-malate dehydrogenase (MDH) gene family (θπ = 0.2 × 10-3) to the pyruvate orthophosphate dikinase (PPDK) gene family (θπ = 5.21 × 10-3). Genetic diversity of C4 genes was reduced by 22.43% in cultivated sorghum compared to wild and weedy sorghum, indicating that the group of wild and weedy sorghum may constitute an untapped reservoir for alleles related to the C4 photosynthetic pathway. A SNP-level analysis identified purifying selection signals on C4 PPDK and carbonic anhydrase (CA) genes, and balancing selection signals on C4 PPDK-regulatory protein (RP) and phosphoenolpyruvate carboxylase (PEPC) genes. Allelic distribution of these C4 genes was consistent with selection signals detected. A better understanding of the genetic diversity of C4 pathway in sorghum paves the way for mining the natural allelic variation for the improvement of photosynthesis.
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Affiliation(s)
- Yongfu Tao
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Hermitage Research Facility, Warwick, QLD 4370, Australia; (Y.T.); (B.G.-J.); (M.B.-P.); (D.J.)
| | - Barbara George-Jaeggli
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Hermitage Research Facility, Warwick, QLD 4370, Australia; (Y.T.); (B.G.-J.); (M.B.-P.); (D.J.)
- Agri-Science Queensland, Department of Agriculture and Fisheries (DAF), Hermitage Research Facility, Warwick, QLD 4370, Australia;
| | - Marie Bouteillé-Pallas
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Hermitage Research Facility, Warwick, QLD 4370, Australia; (Y.T.); (B.G.-J.); (M.B.-P.); (D.J.)
| | | | - Alan Cruickshank
- Agri-Science Queensland, Department of Agriculture and Fisheries (DAF), Hermitage Research Facility, Warwick, QLD 4370, Australia;
| | - David Jordan
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Hermitage Research Facility, Warwick, QLD 4370, Australia; (Y.T.); (B.G.-J.); (M.B.-P.); (D.J.)
| | - Emma Mace
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Hermitage Research Facility, Warwick, QLD 4370, Australia; (Y.T.); (B.G.-J.); (M.B.-P.); (D.J.)
- Agri-Science Queensland, Department of Agriculture and Fisheries (DAF), Hermitage Research Facility, Warwick, QLD 4370, Australia;
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Moody NR, Christin PA, Reid JD. Kinetic Modifications of C 4 PEPC Are Qualitatively Convergent, but Larger in Panicum Than in Flaveria. FRONTIERS IN PLANT SCIENCE 2020; 11:1014. [PMID: 32719709 PMCID: PMC7350407 DOI: 10.3389/fpls.2020.01014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
C4 photosynthesis results from a set of anatomical features and biochemical components that act together to concentrate CO2 within the leaf and boost productivity. This complex trait evolved independently many times, resulting in various realizations of the phenotype, but in all C4 plants the primary fixation of atmospheric carbon is catalyzed by phosphoenolpyruvate carboxylase. Comparisons of C4 and non-C4 PEPC from a few closely related species suggested that the enzyme was modified to meet the demands of the C4 cycle. However, very few C4 groups have been investigated, hampering general conclusions. To test the hypothesis that distant C4 lineages underwent convergent biochemical changes, we compare the kinetic variation between C4 and non-C4 PEPC from a previously assessed young lineage (Flaveria, Asteraceae) with those from an older lineage found within the distantly related grass family (Panicum). Despite the evolutionary distance, the kinetic changes between the non-C4 and C4 PEPC are qualitatively similar, with a decrease in sensitivity for inhibitors, an increased specificity (k cat/K m) for bicarbonate, and a decreased specificity (k cat/K m) for PEP. The differences are more pronounced in the older lineage Panicum, which might indicate that optimization of PEPC for the C4 context increases with evolutionary time.
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Affiliation(s)
- Nicholas R. Moody
- Department of Chemistry, University of Sheffield, Sheffield, United Kingdom
| | | | - James D. Reid
- Department of Chemistry, University of Sheffield, Sheffield, United Kingdom
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13
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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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14
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Carvalho DS, Nishimwe AV, Schnable JC. IsoSeq transcriptome assembly of C 3 panicoid grasses provides tools to study evolutionary change in the Panicoideae. PLANT DIRECT 2020; 4:e00203. [PMID: 32128472 PMCID: PMC7047018 DOI: 10.1002/pld3.203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
The number of plant species with genomic and transcriptomic data has been increasing rapidly. The grasses-Poaceae-have been well represented among species with published reference genomes. However, as a result the genomes of wild grasses are less frequently targeted by sequencing efforts. Sequence data from wild relatives of crop species in the grasses can aid the study of domestication, gene discovery for breeding and crop improvement, and improve our understanding of the evolution of C4 photosynthesis. Here, we used long-read sequencing technology to characterize the transcriptomes of three C3 panicoid grass species: Dichanthelium oligosanthes, Chasmanthium laxum, and Hymenachne amplexicaulis. Based on alignments to the sorghum genome, we estimate that assembled consensus transcripts from each species capture between 54.2% and 65.7% of the conserved syntenic gene space in grasses. Genes co-opted into C4 were also well represented in this dataset, despite concerns that because these genes might play roles unrelated to photosynthesis in the target species, they would be expressed at low levels and missed by transcript-based sequencing. A combined analysis using syntenic orthologous genes from grasses with published reference genomes and consensus long-read sequences from these wild species was consistent with previously published phylogenies. It is hoped that these data, targeting underrepresented classes of species within the PACMAD grasses-wild species and species utilizing C3 photosynthesis-will aid in future studies of domestication and C4 evolution by decreasing the evolutionary distance between C4 and C3 species within this clade, enabling more accurate comparisons associated with evolution of the C4 pathway.
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Affiliation(s)
- Daniel S. Carvalho
- Department of Agronomy and HorticultureCenter for Plant Science InnovationUniversity of Nebraska‐LincolnLincolnNEUSA
| | - Aime V. Nishimwe
- Department of Agronomy and HorticultureCenter for Plant Science InnovationUniversity of Nebraska‐LincolnLincolnNEUSA
| | - James C. Schnable
- Department of Agronomy and HorticultureCenter for Plant Science InnovationUniversity of Nebraska‐LincolnLincolnNEUSA
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15
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Dunning LT, Moreno-Villena JJ, Lundgren MR, Dionora J, Salazar P, Adams C, Nyirenda F, Olofsson JK, Mapaura A, Grundy IM, Kayombo CJ, Dunning LA, Kentatchime F, Ariyarathne M, Yakandawala D, Besnard G, Quick WP, Bräutigam A, Osborne CP, Christin PA. Key changes in gene expression identified for different stages of C4 evolution in Alloteropsis semialata. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3255-3268. [PMID: 30949663 PMCID: PMC6598098 DOI: 10.1093/jxb/erz149] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/19/2019] [Indexed: 05/23/2023]
Abstract
C4 photosynthesis is a complex trait that boosts productivity in tropical conditions. Compared with C3 species, the C4 state seems to require numerous novelties, but species comparisons can be confounded by long divergence times. Here, we exploit the photosynthetic diversity that exists within a single species, the grass Alloteropsis semialata, to detect changes in gene expression associated with different photosynthetic phenotypes. Phylogenetically informed comparative transcriptomics show that intermediates with a weak C4 cycle are separated from the C3 phenotype by increases in the expression of 58 genes (0.22% of genes expressed in the leaves), including those encoding just three core C4 enzymes: aspartate aminotransferase, phosphoenolpyruvate carboxykinase, and phosphoenolpyruvate carboxylase. The subsequent transition to full C4 physiology was accompanied by increases in another 15 genes (0.06%), including only the core C4 enzyme pyruvate orthophosphate dikinase. These changes probably created a rudimentary C4 physiology, and isolated populations subsequently improved this emerging C4 physiology, resulting in a patchwork of expression for some C4 accessory genes. Our work shows how C4 assembly in A. semialata happened in incremental steps, each requiring few alterations over the previous step. These create short bridges across adaptive landscapes that probably facilitated the recurrent origins of C4 photosynthesis through a gradual process of evolution.
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Affiliation(s)
- Luke T Dunning
- Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, UK
| | | | - Marjorie R Lundgren
- Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, UK
| | | | - Paolo Salazar
- International Rice Research Institute, DAPO, Metro Manila, Philippines
| | - Claire Adams
- Botany Department, Rhodes University, Grahamstown, South Africa
| | - Florence Nyirenda
- Department of Biological Sciences, University of Zambia, Lusaka, Zambia
| | - Jill K Olofsson
- Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, UK
| | | | - Isla M Grundy
- Institute of Environmental Studies, University of Zimbabwe, Harare, Zimbabwe
| | | | - Lucy A Dunning
- Department of Social Sciences, University of Sheffield, Sheffield, UK
| | | | - Menaka Ariyarathne
- Department of Botany, Faculty of Science, University of Peradeniya, Peradeiya, Sri Lanka
| | - Deepthi Yakandawala
- Department of Botany, Faculty of Science, University of Peradeniya, Peradeiya, Sri Lanka
| | - Guillaume Besnard
- Laboratoire Évolution et Diversité Biologique (EDB UMR5174), Université de Toulouse, CNRS, IRD, UPS, Toulouse, France
| | - W Paul Quick
- Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, UK
- International Rice Research Institute, DAPO, Metro Manila, Philippines
| | | | - Colin P Osborne
- Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, UK
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16
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17
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Moreno-Villena JJ, Dunning LT, Osborne CP, Christin PA. Highly Expressed Genes Are Preferentially Co-Opted for C4 Photosynthesis. Mol Biol Evol 2019; 35:94-106. [PMID: 29040657 PMCID: PMC5850498 DOI: 10.1093/molbev/msx269] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Novel adaptations are generally assembled by co-opting pre-existing genetic components, but the factors dictating the suitability of genes for new functions remain poorly known. In this work, we used comparative transcriptomics to determine the attributes that increased the likelihood of some genes being co-opted for C4 photosynthesis, a convergent complex trait that boosts productivity in tropical conditions. We show that independent lineages of grasses repeatedly co-opted the gene lineages that were the most highly expressed in non-C4 ancestors to produce their C4 pathway. Although ancestral abundance in leaves explains which genes were used for the emergence of a C4 pathway, the tissue specificity has surprisingly no effect. Our results suggest that levels of key genes were elevated during the early diversification of grasses and subsequently repeatedly used to trigger a weak C4 cycle via relatively few mutations. The abundance of C4-suitable transcripts therefore facilitated physiological innovation, but the transition to a strong C4 pathway still involved consequent changes in expression levels, leaf specificity, and coding sequences. The direction and amount of changes required for the strong C4 pathway depended on the identity of the genes co-opted, so that ancestral gene expression both facilitates adaptive transitions and constrains subsequent evolutionary trajectories.
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Affiliation(s)
| | - Luke T Dunning
- Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Colin P Osborne
- Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
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18
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Niklaus M, Kelly S. The molecular evolution of C4 photosynthesis: opportunities for understanding and improving the world's most productive plants. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:795-804. [PMID: 30462241 DOI: 10.1093/jxb/ery416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 11/09/2018] [Indexed: 05/28/2023]
Abstract
C4 photosynthesis is a convergent evolutionary trait that enhances photosynthetic efficiency in a variety of environmental conditions. It has evolved repeatedly following a fall in atmospheric CO2 concentration such that there is up to a 30 million year difference in the amount of time that natural selection has had to improve C4 function between the oldest and youngest C4 lineages. This large difference in time, coupled with the phylogenetic distance between lineages, has resulted in a large disparity in anatomy, physiology, and biochemistry between extant C4 species. This review summarizes the myriad of molecular sequence changes that have been linked to the evolution of C4 photosynthesis. These range from single nucleotide changes to duplication of entire genes, and provide a roadmap for how natural selection has adapted enzymes and pathways for enhanced C4 function. Finally, this review discusses how this molecular diversity can provide opportunities for understanding and improving photosynthesis for multiple important C4 food, feed, and bioenergy crops.
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Affiliation(s)
- Michael Niklaus
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, Oxford, UK
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19
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Watson-Lazowski A, Papanicolaou A, Sharwood R, Ghannoum O. Investigating the NAD-ME biochemical pathway within C 4 grasses using transcript and amino acid variation in C 4 photosynthetic genes. PHOTOSYNTHESIS RESEARCH 2018; 138:233-248. [PMID: 30078073 DOI: 10.1007/s11120-018-0569-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 07/28/2018] [Indexed: 05/18/2023]
Abstract
Expanding knowledge of the C4 photosynthetic pathway can provide key information to aid biological improvements to crop photosynthesis and yield. While the C4 NADP-ME pathway is well characterised, there is increasing agricultural and bioengineering interest in the comparably understudied NAD-ME and PEPCK pathways. Within this study, a systematic identification of key differences across species has allowed us to investigate the evolution of C4-recruited genes in one C3 and eleven C4 grasses (Poaceae) spanning two independent origins of C4 photosynthesis. We present evidence for C4-specific paralogs of NAD-malic enzyme 2, MPC1 and MPC2 (mitochondrial pyruvate carriers) via increased transcript abundance and associated rates of evolution, implicating them as genes recruited to perform C4 photosynthesis within NAD-ME and PEPCK subtypes. We then investigate the localisation of AspAT across subtypes, using novel and published evidence to place AspAT3 in both the cytosol and peroxisome. Finally, these findings are integrated with transcript abundance of previously identified C4 genes to provide an updated model for C4 grass NAD-ME and PEPCK photosynthesis. This updated model allows us to develop on the current understanding of NAD-ME and PEPCK photosynthesis in grasses, bolstering our efforts to understand the evolutionary 'path to C4' and improve C4 photosynthesis.
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Affiliation(s)
- Alexander Watson-Lazowski
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW, 2751, Australia.
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia.
| | - Alexie Papanicolaou
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW, 2751, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Robert Sharwood
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Oula Ghannoum
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW, 2751, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
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20
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Bianconi ME, Dunning LT, Moreno-Villena JJ, Osborne CP, Christin PA. Gene duplication and dosage effects during the early emergence of C4 photosynthesis in the grass genus Alloteropsis. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1967-1980. [PMID: 29394370 PMCID: PMC6018922 DOI: 10.1093/jxb/ery029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/17/2018] [Indexed: 05/04/2023]
Abstract
The importance of gene duplication for evolutionary diversification has been mainly discussed in terms of genetic redundancy allowing neofunctionalization. In the case of C4 photosynthesis, which evolved via the co-option of multiple enzymes to boost carbon fixation in tropical conditions, the importance of genetic redundancy has not been consistently supported by genomic studies. Here, we test for a different role for gene duplication in the early evolution of C4 photosynthesis, via dosage effects creating rapid step changes in expression levels. Using genome-wide data for accessions of the grass genus Alloteropsis that recently diversified into different photosynthetic types, we estimate gene copy numbers and demonstrate that recurrent duplications in two important families of C4 genes coincided with increases in transcript abundance along the phylogeny, in some cases via a pure dosage effect. While increased gene copy number during the initial emergence of C4 photosynthesis probably offered a rapid route to enhanced expression, we also find losses of duplicates following the acquisition of genes encoding better-suited isoforms. The dosage effect of gene duplication might therefore act as a transient process during the evolution of a C4 biochemistry, rendered obsolete by the fixation of regulatory mutations increasing expression levels.
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Affiliation(s)
- Matheus E Bianconi
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Luke T Dunning
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | | | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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21
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Kolbe AR, Studer AJ, Cousins AB. Biochemical and transcriptomic analysis of maize diversity to elucidate drivers of leaf carbon isotope composition. FUNCTIONAL PLANT BIOLOGY : FPB 2018; 45:489-500. [PMID: 32290988 DOI: 10.1071/fp17265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 11/01/2017] [Indexed: 05/13/2023]
Abstract
Carbon isotope discrimination is used to study CO2 diffusion, substrate availability for photosynthesis, and leaf biochemistry, but the intraspecific drivers of leaf carbon isotope composition (δ13C) in C4 species are not well understood. In this study, the role of photosynthetic enzymes and post-photosynthetic fractionation on δ13C (‰) was explored across diverse maize inbred lines. A significant 1.3‰ difference in δ13C was observed between lines but δ13C did not correlate with in vitro leaf carbonic anhydrase (CA), phosphoenolpyruvate carboxylase (PEPC), or ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity. RNA-sequencing was used to identify potential differences in post-photosynthetic metabolism that would influence δ13C; however, no correlations were identified that would indicate significant differences in post-photosynthetic fractionation between lines. Variation in δ13C has been observed between C4 subtypes, but differential expression of NADP-ME and PEP-CK pathways within these lines did not correlate with δ13C. However, co-expression network analysis provided novel evidence for isoforms of C4 enzymes and putative transporters. Together, these data indicate that diversity in maize δ13C cannot be fully explained by variation in CA, PEPC, or Rubisco activity or gene expression. The findings further emphasise the need for future work exploring the influence of stomatal sensitivity and mesophyll conductance on δ13C in maize.
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Affiliation(s)
- Allison R Kolbe
- School of Biological Sciences, PO Box 644236, Washington State University, Pullman, WA 99164, USA
| | - Anthony J Studer
- Department of Crop Sciences, 1201 West Gregory Drive, Edward R. Madigan Laboratory 289, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Asaph B Cousins
- School of Biological Sciences, PO Box 644236, Washington State University, Pullman, WA 99164, USA
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22
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Zhang S, Tang S, Tang C, Luo M, Jia G, Zhi H, Diao X. SiSTL2 Is Required for Cell Cycle, Leaf Organ Development, Chloroplast Biogenesis, and Has Effects on C 4 Photosynthesis in Setaria italica (L.) P. Beauv. FRONTIERS IN PLANT SCIENCE 2018; 9:1103. [PMID: 30105043 PMCID: PMC6077218 DOI: 10.3389/fpls.2018.01103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/09/2018] [Indexed: 05/20/2023]
Abstract
Deoxycytidine monophosphate deaminase (DCD) is a key enzyme in the de novo dTTP biosynthesis pathway. Previous studies have indicated that DCD plays key roles in the maintenance of the balance of dNTP pools, cell cycle progression, and plant development. However, few studies have elucidated the functions of the DCD gene in Panicoideae plants. Setaria has been proposed as an ideal model of Panicoideae grasses, especially for C4 photosynthesis research. Here, a Setaria italica stripe leaf mutant (sistl2) was isolated from EMS-induced lines of "Yugu1," the wild-type parent. The sistl2 mutant exhibited semi-dwarf, striped leaves, abnormal chloroplast ultrastructure, and delayed cell cycle progression compared with Yugu1. High-throughput sequencing and map-based cloning identified the causal gene SiSTL2, which encodes a DCD protein. The occurrence of a single-base G to A substitution in the fifth intron introduced alternative splicing, which led to the early termination of translation. Further physiological and transcriptomic investigation indicated that SiSTL2 plays an essential role in the regulation of chloroplast biogenesis, cell cycle, and DNA replication, which suggested that the gene has conserved functions in both foxtail millet and rice. Remarkably, in contrast to DCD mutants in C3 rice, sistl2 showed a significant reduction in leaf cell size and affected C4 photosynthetic capacity in foxtail millet. qPCR showed that SiSTL2 had a similar expression pattern to typical C4 genes in response to a low CO2 environment. Moreover, the loss of function of SiSTL2 resulted in a reduction of leaf 13C content and the enrichment of DEGs in photosynthetic carbon fixation. Our research provides in-depth knowledge of the role of DCD in the C4 photosynthesis model S. italica and proposed new directions for further study of the function of DCD.
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Affiliation(s)
- Shuo Zhang
- These authors have contributed equally to this work
| | - Sha Tang
- These authors have contributed equally to this work
| | | | | | | | - Hui Zhi
- *Correspondence: Hui Zhi, Xianmin Diao,
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23
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Moreno-Villena JJ, Dunning LT, Osborne CP, Christin PA. Highly Expressed Genes Are Preferentially Co-Opted for C4 Photosynthesis. Mol Biol Evol 2018. [PMID: 29040657 DOI: 10.1093/molbev/msx269/4457558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Novel adaptations are generally assembled by co-opting pre-existing genetic components, but the factors dictating the suitability of genes for new functions remain poorly known. In this work, we used comparative transcriptomics to determine the attributes that increased the likelihood of some genes being co-opted for C4 photosynthesis, a convergent complex trait that boosts productivity in tropical conditions. We show that independent lineages of grasses repeatedly co-opted the gene lineages that were the most highly expressed in non-C4 ancestors to produce their C4 pathway. Although ancestral abundance in leaves explains which genes were used for the emergence of a C4 pathway, the tissue specificity has surprisingly no effect. Our results suggest that levels of key genes were elevated during the early diversification of grasses and subsequently repeatedly used to trigger a weak C4 cycle via relatively few mutations. The abundance of C4-suitable transcripts therefore facilitated physiological innovation, but the transition to a strong C4 pathway still involved consequent changes in expression levels, leaf specificity, and coding sequences. The direction and amount of changes required for the strong C4 pathway depended on the identity of the genes co-opted, so that ancestral gene expression both facilitates adaptive transitions and constrains subsequent evolutionary trajectories.
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Affiliation(s)
| | - Luke T Dunning
- Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Colin P Osborne
- Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
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Scheben A, Wolter F, Batley J, Puchta H, Edwards D. Towards CRISPR/Cas crops - bringing together genomics and genome editing. THE NEW PHYTOLOGIST 2017; 216:682-698. [PMID: 28762506 DOI: 10.1111/nph.14702] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 05/31/2017] [Indexed: 05/19/2023]
Abstract
Contents 682 I. 682 II. 683 III. 684 IV. 685 V. 685 VI. 688 VII. 690 VIII. 694 694 References 694 SUMMARY: With the rapid increase in the global population and the impact of climate change on agriculture, there is a need for crops with higher yields and greater tolerance to abiotic stress. However, traditional crop improvement via genetic recombination or random mutagenesis is a laborious process and cannot keep pace with increasing crop demand. Genome editing technologies such as clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (CRISPR/Cas) allow targeted modification of almost any crop genome sequence to generate novel variation and accelerate breeding efforts. We expect a gradual shift in crop improvement away from traditional breeding towards cycles of targeted genome editing. Crop improvement using genome editing is not constrained by limited existing variation or the requirement to select alleles over multiple breeding generations. However, current applications of crop genome editing are limited by the lack of complete reference genomes, the sparse knowledge of potential modification targets, and the unclear legal status of edited crops. We argue that overcoming technical and social barriers to the application of genome editing will allow this technology to produce a new generation of high-yielding, climate ready crops.
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Affiliation(s)
- Armin Scheben
- School of Biological Sciences and Institute of Agriculture, University of Western Australia, Perth, WA, 6009, Australia
| | - Felix Wolter
- Botanical Institute II, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany
| | - Jacqueline Batley
- School of Biological Sciences and Institute of Agriculture, University of Western Australia, Perth, WA, 6009, Australia
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany
| | - David Edwards
- School of Biological Sciences and Institute of Agriculture, University of Western Australia, Perth, WA, 6009, Australia
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25
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Orr DJ, Pereira AM, da Fonseca Pereira P, Pereira-Lima ÍA, Zsögön A, Araújo WL. Engineering photosynthesis: progress and perspectives. F1000Res 2017; 6:1891. [PMID: 29263782 PMCID: PMC5658708 DOI: 10.12688/f1000research.12181.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/27/2017] [Indexed: 12/11/2022] Open
Abstract
Photosynthesis is the basis of primary productivity on the planet. Crop breeding has sustained steady improvements in yield to keep pace with population growth increases. Yet these advances have not resulted from improving the photosynthetic process
per se but rather of altering the way carbon is partitioned within the plant. Mounting evidence suggests that the rate at which crop yields can be boosted by traditional plant breeding approaches is wavering, and they may reach a “yield ceiling” in the foreseeable future. Further increases in yield will likely depend on the targeted manipulation of plant metabolism. Improving photosynthesis poses one such route, with simulations indicating it could have a significant transformative influence on enhancing crop productivity. Here, we summarize recent advances of alternative approaches for the manipulation and enhancement of photosynthesis and their possible application for crop improvement.
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Affiliation(s)
- Douglas J Orr
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Auderlan M Pereira
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Paula da Fonseca Pereira
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Ítalo A Pereira-Lima
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Agustin Zsögön
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Wagner L Araújo
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.,Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
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Hittalmani S, Mahesh HB, Shirke MD, Biradar H, Uday G, Aruna YR, Lohithaswa HC, Mohanrao A. Genome and Transcriptome sequence of Finger millet (Eleusine coracana (L.) Gaertn.) provides insights into drought tolerance and nutraceutical properties. BMC Genomics 2017; 18:465. [PMID: 28619070 PMCID: PMC5472924 DOI: 10.1186/s12864-017-3850-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/07/2017] [Indexed: 12/18/2022] Open
Abstract
Background Finger millet (Eleusine coracana (L.) Gaertn.) is an important staple food crop widely grown in Africa and South Asia. Among the millets, finger millet has high amount of calcium, methionine, tryptophan, fiber, and sulphur containing amino acids. In addition, it has C4 photosynthetic carbon assimilation mechanism, which helps to utilize water and nitrogen efficiently under hot and arid conditions without severely affecting yield. Therefore, development and utilization of genomic resources for genetic improvement of this crop is immensely useful. Results Experimental results from whole genome sequencing and assembling process of ML-365 finger millet cultivar yielded 1196 Mb covering approximately 82% of total estimated genome size. Genome analysis showed the presence of 85,243 genes and one half of the genome is repetitive in nature. The finger millet genome was found to have higher colinearity with foxtail millet and rice as compared to other Poaceae species. Mining of simple sequence repeats (SSRs) yielded abundance of SSRs within the finger millet genome. Functional annotation and mining of transcription factors revealed finger millet genome harbors large number of drought tolerance related genes. Transcriptome analysis of low moisture stress and non-stress samples revealed the identification of several drought-induced candidate genes, which could be used in drought tolerance breeding. Conclusions This genome sequencing effort will strengthen plant breeders for allele discovery, genetic mapping, and identification of candidate genes for agronomically important traits. Availability of genomic resources of finger millet will enhance the novel breeding possibilities to address potential challenges of finger millet improvement. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3850-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shailaja Hittalmani
- Marker Assisted Selection Laboratory, Department of Genetics and Plant Breeding, University of Agricultural Sciences, Bengaluru, 560065, India.
| | - H B Mahesh
- Marker Assisted Selection Laboratory, Department of Genetics and Plant Breeding, University of Agricultural Sciences, Bengaluru, 560065, India.
| | | | - Hanamareddy Biradar
- Marker Assisted Selection Laboratory, Department of Genetics and Plant Breeding, University of Agricultural Sciences, Bengaluru, 560065, India
| | - Govindareddy Uday
- Marker Assisted Selection Laboratory, Department of Genetics and Plant Breeding, University of Agricultural Sciences, Bengaluru, 560065, India
| | - Y R Aruna
- Marker Assisted Selection Laboratory, Department of Genetics and Plant Breeding, University of Agricultural Sciences, Bengaluru, 560065, India
| | - H C Lohithaswa
- Department of Genetics and Plant Breeding, College of Agriculture, V. C. Farm, University of Agricultural Sciences, Mandya, 571405, India
| | - A Mohanrao
- Marker Assisted Selection Laboratory, Department of Genetics and Plant Breeding, University of Agricultural Sciences, Bengaluru, 560065, India
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Dunning LT, Lundgren MR, Moreno-Villena JJ, Namaganda M, Edwards EJ, Nosil P, Osborne CP, Christin PA. Introgression and repeated co-option facilitated the recurrent emergence of C 4 photosynthesis among close relatives. Evolution 2017; 71:1541-1555. [PMID: 28395112 PMCID: PMC5488178 DOI: 10.1111/evo.13250] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 04/04/2017] [Indexed: 01/16/2023]
Abstract
The origins of novel traits are often studied using species trees and modeling phenotypes as different states of the same character, an approach that cannot always distinguish multiple origins from fewer origins followed by reversals. We address this issue by studying the origins of C4 photosynthesis, an adaptation to warm and dry conditions, in the grass Alloteropsis. We dissect the C4 trait into its components, and show two independent origins of the C4 phenotype via different anatomical modifications, and the use of distinct sets of genes. Further, inference of enzyme adaptation suggests that one of the two groups encompasses two transitions to a full C4 state from a common ancestor with an intermediate phenotype that had some C4 anatomical and biochemical components. Molecular dating of C4 genes confirms the introgression of two key C4 components between species, while the inheritance of all others matches the species tree. The number of origins consequently varies among C4 components, a scenario that could not have been inferred from analyses of the species tree alone. Our results highlight the power of studying individual components of complex traits to reconstruct trajectories toward novel adaptations.
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Affiliation(s)
- Luke T Dunning
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Marjorie R Lundgren
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Jose J Moreno-Villena
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | | | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, 02912
| | - Patrik Nosil
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Pascal-Antoine Christin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
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Christin PA. Traces of strong selective pressures in the genomes of C4 grasses. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:103-105. [PMID: 28110275 PMCID: PMC5853578 DOI: 10.1093/jxb/erw390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
C4 photosynthesis is nature's response to CO2 limitations, and evolved recurrently in several groups of plants. To identify genes related to C4 photosynthesis, Huang et al. looked for evidence of past episodes of adaptive evolution in the genomes of C4 grasses. They identified a large number of candidate genes that evolved under divergent selection, indicating that, besides alterations to expression patterns, the history of C4 involved strong selection on protein-coding sequences.
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29
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von Caemmerer S, Ghannoum O, Furbank RT. C4 photosynthesis: 50 years of discovery and innovation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:97-102. [PMID: 28110274 PMCID: PMC5444450 DOI: 10.1093/jxb/erw491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
It is now over half a century since the biochemical characterization of the C4 photosynthetic pathway, and this special issue highlights the sheer breadth of current knowledge. New genomic and transcriptomic information shows that multi-level regulation of gene expression is required for the pathway to function, yet we know it to be one of the most dynamic examples of convergent evolution. Now, a focus on the molecular transition from C3-C4 intermediates, together with improved mathematical models, experimental tools and transformation systems, holds great promise for improving C4 photosynthesis in crops.
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Affiliation(s)
- Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW 2753, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
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Kümpers BMC, Burgess SJ, Reyna-Llorens I, Smith-Unna R, Boursnell C, Hibberd JM. Shared characteristics underpinning C4 leaf maturation derived from analysis of multiple C3 and C4 species of Flaveria. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:177-189. [PMID: 28062590 PMCID: PMC5853325 DOI: 10.1093/jxb/erw488] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/13/2016] [Indexed: 05/08/2023]
Abstract
Most terrestrial plants use C3 photosynthesis to fix carbon. In multiple plant lineages a modified system known as C4 photosynthesis has evolved. To better understand the molecular patterns associated with induction of C4 photosynthesis, the genus Flaveria that contains C3 and C4 species was used. A base to tip maturation gradient of leaf anatomy was defined, and RNA sequencing was undertaken along this gradient for two C3 and two C4 Flaveria species. Key C4 traits including vein density, mesophyll and bundle sheath cross-sectional area, chloroplast ultrastructure, and abundance of transcripts encoding proteins of C4 photosynthesis were quantified. Candidate genes underlying each of these C4 characteristics were identified. Principal components analysis indicated that leaf maturation and the photosynthetic pathway were responsible for the greatest amount of variation in transcript abundance. Photosynthesis genes were over-represented for a prolonged period in the C4 species. Through comparison with publicly available data sets, we identify a small number of transcriptional regulators that have been up-regulated in diverse C4 species. The analysis identifies similar patterns of expression in independent C4 lineages and so indicates that the complex C4 pathway is associated with parallel as well as convergent evolution.
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Affiliation(s)
- Britta M C Kümpers
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Steven J Burgess
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Ivan Reyna-Llorens
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Richard Smith-Unna
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Chris Boursnell
- 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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31
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Olofsson JK, Bianconi M, Besnard G, Dunning LT, Lundgren MR, Holota H, Vorontsova MS, Hidalgo O, Leitch IJ, Nosil P, Osborne CP, Christin P. Genome biogeography reveals the intraspecific spread of adaptive mutations for a complex trait. Mol Ecol 2016; 25:6107-6123. [PMID: 27862505 PMCID: PMC6849575 DOI: 10.1111/mec.13914] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 10/27/2016] [Accepted: 11/09/2016] [Indexed: 01/17/2023]
Abstract
Physiological novelties are often studied at macro-evolutionary scales such that their micro-evolutionary origins remain poorly understood. Here, we test the hypothesis that key components of a complex trait can evolve in isolation and later be combined by gene flow. We use C4 photosynthesis as a study system, a derived physiology that increases plant productivity in warm, dry conditions. The grass Alloteropsis semialata includes C4 and non-C4 genotypes, with some populations using laterally acquired C4 -adaptive loci, providing an outstanding system to track the spread of novel adaptive mutations. Using genome data from C4 and non-C4 A. semialata individuals spanning the species' range, we infer and date past migrations of different parts of the genome. Our results show that photosynthetic types initially diverged in isolated populations, where key C4 components were acquired. However, rare but recurrent subsequent gene flow allowed the spread of adaptive loci across genetic pools. Indeed, laterally acquired genes for key C4 functions were rapidly passed between populations with otherwise distinct genomic backgrounds. Thus, our intraspecific study of C4 -related genomic variation indicates that components of adaptive traits can evolve separately and later be combined through secondary gene flow, leading to the assembly and optimization of evolutionary innovations.
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Affiliation(s)
- Jill K. Olofsson
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | - Matheus Bianconi
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | - Guillaume Besnard
- Laboratoire Évolution & Diversité Biologique (EDB UMR5174)Université de ToulouseCNRS, ENSFEA, UPS118 route de NarbonneF‐31062ToulouseFrance
| | - Luke T. Dunning
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | - Marjorie R. Lundgren
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | - Helene Holota
- Laboratoire Évolution & Diversité Biologique (EDB UMR5174)Université de ToulouseCNRS, ENSFEA, UPS118 route de NarbonneF‐31062ToulouseFrance
| | | | | | | | - Patrik Nosil
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | - Colin P. Osborne
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | - Pascal‐Antoine Christin
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
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Huang P, Shyu C, Coelho CP, Cao Y, Brutnell TP. Setaria viridis as a Model System to Advance Millet Genetics and Genomics. FRONTIERS IN PLANT SCIENCE 2016; 7:1781. [PMID: 27965689 PMCID: PMC5124564 DOI: 10.3389/fpls.2016.01781] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/11/2016] [Indexed: 05/18/2023]
Abstract
Millet is a common name for a group of polyphyletic, small-seeded cereal crops that include pearl, finger and foxtail millet. Millet species are an important source of calories for many societies, often in developing countries. Compared to major cereal crops such as rice and maize, millets are generally better adapted to dry and hot environments. Despite their food security value, the genetic architecture of agronomically important traits in millets, including both morphological traits and climate resilience remains poorly studied. These complex traits have been challenging to dissect in large part because of the lack of sufficient genetic tools and resources. In this article, we review the phylogenetic relationship among various millet species and discuss the value of a genetic model system for millet research. We propose that a broader adoption of green foxtail (Setaria viridis) as a model system for millets could greatly accelerate the pace of gene discovery in the millets, and summarize available and emerging resources in S. viridis and its domesticated relative S. italica. These resources have value in forward genetics, reverse genetics and high throughput phenotyping. We describe methods and strategies to best utilize these resources to facilitate the genetic dissection of complex traits. We envision that coupling cutting-edge technologies and the use of S. viridis for gene discovery will accelerate genetic research in millets in general. This will enable strategies and provide opportunities to increase productivity, especially in the semi-arid tropics of Asia and Africa where millets are staple food crops.
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