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Gilman IS, Heyduk K, Maya-Lastra C, Hancock LP, Edwards EJ. Predicting photosynthetic pathway from anatomy using machine learning. THE NEW PHYTOLOGIST 2024; 242:1029-1042. [PMID: 38173400 DOI: 10.1111/nph.19488] [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: 08/31/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024]
Abstract
Plants with Crassulacean acid metabolism (CAM) have long been associated with a specialized anatomy, including succulence and thick photosynthetic tissues. Firm, quantitative boundaries between non-CAM and CAM plants have yet to be established - if they indeed exist. Using novel computer vision software to measure anatomy, we combined new measurements with published data across flowering plants. We then used machine learning and phylogenetic comparative methods to investigate relationships between CAM and anatomy. We found significant differences in photosynthetic tissue anatomy between plants with differing CAM phenotypes. Machine learning-based classification was over 95% accurate in differentiating CAM from non-CAM anatomy, and had over 70% recall of distinct CAM phenotypes. Phylogenetic least squares regression and threshold analyses revealed that CAM evolution was significantly correlated with increased mesophyll cell size, thicker leaves, and decreased intercellular airspace. Our findings suggest that machine learning may be used to aid the discovery of new CAM species and that the evolutionary trajectory from non-CAM to strong, obligate CAM requires continual anatomical specialization.
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Affiliation(s)
- Ian S Gilman
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Karolina Heyduk
- Department of Ecology and Evolutionary Biology, The University of Connecticut, Storrs, CT, 06269, USA
| | - Carlos Maya-Lastra
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
- Department of Biology, Angelo State University, San Angelo, TX, 76909, USA
| | - Lillian P Hancock
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
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2
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Chen M, Li D, Meng X, Sun Y, Liu R, Sun T. Review of isolation, purification, structural characteristics and bioactivities of polysaccharides from Portulaca oleracea L. Int J Biol Macromol 2024; 257:128565. [PMID: 38061516 DOI: 10.1016/j.ijbiomac.2023.128565] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/23/2023] [Accepted: 11/30/2023] [Indexed: 01/26/2024]
Abstract
Portulaca oleracea L., also known as purslane, affiliates to the Portulacaceae family. It is an herbaceous succulent annual plant distributed worldwide. P. oleracea L. is renowned for its nutritional value and medicinal value, which has been utilized for thousands of years as Traditional Chinese Medicine (TCM). The extract derived from P. oleracea L. has shown efficacy in treating various diseases, including intestinal dysfunction and inflammation. Polysaccharides from P. oleracea L. (POP) are the primary constituents of the crude extract which have been found to have various biological activities, including antioxidant, antitumor, immune-stimulating, and intestinal protective effects. While many publications have highlighted on the structural identification and bioactivity evaluation of POP, the underlying structure-activity relationship of POP still remains unclear. In view of this, this review aims to focus on the extraction, purification, structural features and bioactivities of POP. In addition, the potential structure-activity relationship and the developmental perspective for future research of POP were also explored and discussed. The current review would provide a valuable research foundation and the up-to-date information for the future development and application of POP in the field of the functional foods and medicine.
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Affiliation(s)
- Mengjie Chen
- Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China
| | - Dan Li
- Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China
| | - Xianwei Meng
- Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China
| | - Yuan Sun
- Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China.
| | - Rui Liu
- Center of Pharmaceutical Engineering and Technology, Harbin University of Commerce, Harbin 150076, China.
| | - Tiedong Sun
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China.
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3
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Gilman IS, Smith JAC, Holtum JAM, Sage RF, Silvera K, Winter K, Edwards EJ. The CAM lineages of planet Earth. ANNALS OF BOTANY 2023; 132:627-654. [PMID: 37698538 PMCID: PMC10799995 DOI: 10.1093/aob/mcad135] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/09/2023] [Accepted: 09/11/2023] [Indexed: 09/13/2023]
Abstract
BACKGROUND AND SCOPE The growth of experimental studies of crassulacean acid metabolism (CAM) in diverse plant clades, coupled with recent advances in molecular systematics, presents an opportunity to re-assess the phylogenetic distribution and diversity of species capable of CAM. It has been more than two decades since the last comprehensive lists of CAM taxa were published, and an updated survey of the occurrence and distribution of CAM taxa is needed to facilitate and guide future CAM research. We aimed to survey the phylogenetic distribution of these taxa, their diverse morphology, physiology and ecology, and the likely number of evolutionary origins of CAM based on currently known lineages. RESULTS AND CONCLUSIONS We found direct evidence (in the form of experimental or field observations of gas exchange, day-night fluctuations in organic acids, carbon isotope ratios and enzymatic activity) for CAM in 370 genera of vascular plants, representing 38 families. Further assumptions about the frequency of CAM species in CAM clades and the distribution of CAM in the Cactaceae and Crassulaceae bring the currently estimated number of CAM-capable species to nearly 7 % of all vascular plants. The phylogenetic distribution of these taxa suggests a minimum of 66 independent origins of CAM in vascular plants, possibly with dozens more. To achieve further insight into CAM origins, there is a need for more extensive and systematic surveys of previously unstudied lineages, particularly in living material to identify low-level CAM activity, and for denser sampling to increase phylogenetic resolution in CAM-evolving clades. This should allow further progress in understanding the functional significance of this pathway by integration with studies on the evolution and genomics of CAM in its many forms.
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Affiliation(s)
- Ian S Gilman
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | | | - Joseph A M Holtum
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Katia Silvera
- Smithsonian Tropical Research Institute, Balboa, Ancón, Panama
- Department of Botany & Plant Sciences, University of California, Riverside, CA, USA
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Balboa, Ancón, Panama
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
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Berasategui JA, Žerdoner Čalasan A, Zizka A, Kadereit G. Global distribution, climatic preferences and photosynthesis-related traits of C 4 eudicots and how they differ from those of C 4 grasses. Ecol Evol 2023; 13:e10720. [PMID: 37964791 PMCID: PMC10641307 DOI: 10.1002/ece3.10720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/16/2023] Open
Abstract
C₄ is one of three known photosynthetic processes of carbon fixation in flowering plants. It evolved independently more than 61 times in multiple angiosperm lineages and consists of a series of anatomical and biochemical modifications to the ancestral C3 pathway increasing plant productivity under warm and light-rich conditions. The C4 lineages of eudicots belong to seven orders and 15 families, are phylogenetically less constrained than those of monocots and entail an enormous structural and ecological diversity. Eudicot C4 lineages likely evolved the C4 syndrome along different evolutionary paths. Therefore, a better understanding of this diversity is key to understanding the evolution of this complex trait as a whole. By compiling 1207 recognised C4 eudicots species described in the literature and presenting trait data among these species, we identify global centres of species richness and of high phylogenetic diversity. Furthermore, we discuss climatic preferences in the context of plant functional traits. We identify two hotspots of C4 eudicot diversity: arid regions of Mexico/Southern United States and Australia, which show a similarly high number of different C4 eudicot genera but differ in the number of C4 lineages that evolved in situ. Further eudicot C4 hotspots with many different families and genera are in South Africa, West Africa, Patagonia, Central Asia and the Mediterranean. In general, C4 eudicots are diverse in deserts and xeric shrublands, tropical and subtropical grasslands, savannas and shrublands. We found C4 eudicots to occur in areas with less annual precipitation than C4 grasses which can be explained by frequently associated adaptations to drought stress such as among others succulence and salt tolerance. The data indicate that C4 eudicot lineages utilising the NAD-ME decarboxylating enzyme grow in drier areas than those using the NADP-ME decarboxylating enzyme indicating biochemical restrictions of the later system in higher temperatures. We conclude that in most eudicot lineages, C4 evolved in ancestrally already drought-adapted clades and enabled these to further spread in these habitats and colonise even drier areas.
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Affiliation(s)
- Jessica A. Berasategui
- Prinzessin Therese von Bayern Lehrstuhl für Systematik, Biodiversität & Evolution der PflanzenLudwig‐Maximilians Universität MünchenMünchenGermany
- Institute for Molecular PhysiologyJohannes Gutenberg‐University MainzMainzGermany
| | - Anže Žerdoner Čalasan
- Prinzessin Therese von Bayern Lehrstuhl für Systematik, Biodiversität & Evolution der PflanzenLudwig‐Maximilians Universität MünchenMünchenGermany
| | - Alexander Zizka
- Department of BiologyPhilipps‐University MarburgMarburgGermany
| | - Gudrun Kadereit
- Prinzessin Therese von Bayern Lehrstuhl für Systematik, Biodiversität & Evolution der PflanzenLudwig‐Maximilians Universität MünchenMünchenGermany
- Botanischer Garten München‐Nymphenburg und Botanische Staatssammlung MünchenStaatliche Naturwissenschaftliche Sammlungen BayernsMünchenGermany
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Kumar A, Sreedharan S, Singh P, Achigan-Dako EG, Ramchiary N. Improvement of a Traditional Orphan Food Crop, Portulaca oleracea L. (Purslane) Using Genomics for Sustainable Food Security and Climate-Resilient Agriculture. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2021.711820] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purslane (Portulaca oleracea L.) is a popular orphan crop used for its nutritional properties in various parts of the world. It is considered one of the richest terrestrial sources of omega-3 and omega-6-fatty acids (ω-3 and 6-FAs) suggesting its importance for human health. This ethnomedicinal plant is also an important part of traditional healing systems among the indigenous people. Many studies have indicated its tolerance against multiple stresses and found that it easily grows in a range of environmental gradients. It has also been considered one of the important biosaline crops for the future. Despite its huge nutritional, economic, and medicinal importance, it remains neglected to date. Most of the studies on purslane were focused on its ethnomedicinal, phytochemical, pharmacological, and stress-tolerance properties. Only a few studies have attempted genetic dissection of the traits governing these traits. Purslane being an important traditional food crop across the globe can be valorized for a sustainable food security in the future. Therefore, this review is an attempt to highlight the distribution, domestication, and cultivation of purslane and its importance as an important stress-tolerant food and a biosaline crop. Furthermore, identification of genes and their functions governing important traits and its potential for improvement using genomics tools for smart and biosaline agriculture has been discussed.
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6
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Winter K, Garcia M, Virgo A, Ceballos J, Holtum JAM. Does the C 4 plant Trianthema portulacastrum (Aizoaceae) exhibit weakly expressed crassulacean acid metabolism (CAM)? FUNCTIONAL PLANT BIOLOGY : FPB 2021; 48:655-665. [PMID: 33213694 DOI: 10.1071/fp20247] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
We examined whether crassulacean acid metabolism (CAM) is present in Trianthema portulacastrum L. (Aizoaceae), a pantropical, salt-tolerant C4 annual herb with atriplicoid-type Kranz anatomy in leaves but not in stems. The leaves of T. portulacastrum are slightly succulent and the stems are fleshy, similar to some species of Portulaca, the only genus known in which C4 and CAM co-occur. Low- level nocturnal acidification typical of weakly expressed, predominantly constitutive CAM was measured in plants grown for their entire life-cycle in an outdoor raised garden box. Acidification was greater in stems than in leaves. Plants showed net CO2 uptake only during the light irrespective of soil water availability. However, nocturnal traces of CO2 exchange exhibited curved kinetics of reduced CO2 loss during the middle of the night consistent with low-level CAM. Trianthema becomes the second genus of vascular land plants in which C4 and features of CAM have been demonstrated to co-occur in the same plant and the first C4 plant with CAM-type acidification described for the Aizoaceae. Traditionally the stems of herbs are not sampled in screening studies. Small herbs with mildly succulent leaves and fleshy stems might be a numerically significant component of CAM biodiversity.
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Affiliation(s)
- Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama; and Corresponding author.
| | - Milton Garcia
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
| | - Aurelio Virgo
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
| | - Jorge Ceballos
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
| | - Joseph A M Holtum
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama; and College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia
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7
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Hnilickova H, Kraus K, Vachova P, Hnilicka F. Salinity Stress Affects Photosynthesis, Malondialdehyde Formation, and Proline Content in Portulaca oleracea L. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10050845. [PMID: 33922210 PMCID: PMC8145623 DOI: 10.3390/plants10050845] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 05/26/2023]
Abstract
In this investigation, the effect of salt stress on Portulaca oleracea L. was monitored at salinity levels of 100 and 300 mM NaCl. At a concentration of 100 mM NaCl there was a decrease in stomatal conductance (gs) simultaneously with an increase in CO2 assimilation (A) at the beginning of salt exposure (day 3). However, the leaf water potential (ψw), the substomatal concentration of CO2 (Ci), the maximum quantum yield of photosystem II (Fv/Fm), and the proline and malondialdehyde (MDA) content remained unchanged. Exposure to 300 mM NaCl caused a decrease in gs from day 3 and a decrease in water potential, CO2 assimilation, and Fv/Fm from day 9. There was a large increase in proline content and a significantly higher MDA concentration on days 6 and 9 of salt stress compared to the control group. After 22 days of exposure to 300 mM NaCl, there was a transition from the C4 cycle to crassulacean acid metabolism (CAM), manifested by a rapid increase in substomatal CO2 concentration and negative CO2 assimilation values. These results document the tolerance of P. oleracea to a lower level of salt stress and the possibility of its use in saline localities.
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8
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Khoshravesh R, Stata M, Adachi S, Sage TL, Sage RF. Evolutionary Convergence of C 4 Photosynthesis: A Case Study in the Nyctaginaceae. FRONTIERS IN PLANT SCIENCE 2020; 11:578739. [PMID: 33224166 PMCID: PMC7667235 DOI: 10.3389/fpls.2020.578739] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/06/2020] [Indexed: 05/27/2023]
Abstract
C4 photosynthesis evolved over 65 times, with around 24 origins in the eudicot order Caryophyllales. In the Caryophyllales family Nyctaginaceae, the C4 pathway is known in three genera of the tribe Nyctagineae: Allionia, Okenia and Boerhavia. Phylogenetically, Allionia and Boerhavia/Okenia are separated by three genera whose photosynthetic pathway is uncertain. To clarify the distribution of photosynthetic pathways in the Nyctaginaceae, we surveyed carbon isotope ratios of 159 species of the Nyctaginaceae, along with bundle sheath (BS) cell ultrastructure, leaf gas exchange, and C4 pathway biochemistry in five species from the two C4 clades and closely related C3 genera. All species in Allionia, Okenia and Boerhavia are C4, while no C4 species occur in any other genera of the family, including three that branch between Allionia and Boerhavia. This demonstrates that C4 photosynthesis evolved twice in Nyctaginaceae. Boerhavia species use the NADP-malic enzyme (NADP-ME) subtype of C4 photosynthesis, while Allionia species use the NAD-malic enzyme (NAD-ME) subtype. The BS cells of Allionia have many more mitochondria than the BS of Boerhavia. Bundle sheath mitochondria are closely associated with chloroplasts in Allionia which facilitates CO2 refixation following decarboxylation by mitochondrial NAD-ME. The close relationship between Allionia and Boerhavia could provide insights into why NADP-ME versus NAD-ME subtypes evolve, particularly when coupled to analysis of their respective genomes. As such, the group is an excellent system to dissect the organizational hierarchy of convergent versus divergent traits produced by C4 evolution, enabling us to understand when convergence is favored versus when divergent modifications can result in a common phenotype.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
- Department of Biology, The University of New Mexico, Albuquerque, NM, United States
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
| | - Shunsuke Adachi
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tammy L. Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
| | - Rowan F. Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
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9
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Ferrari RC, Cruz BC, Gastaldi VD, Storl T, Ferrari EC, Boxall SF, Hartwell J, Freschi L. Exploring C 4-CAM plasticity within the Portulaca oleracea complex. Sci Rep 2020; 10:14237. [PMID: 32859905 PMCID: PMC7455729 DOI: 10.1038/s41598-020-71012-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 07/29/2020] [Indexed: 11/21/2022] Open
Abstract
Portulaca oleracea is a C4 herb capable of performing CAM under drought stress. It is distributed worldwide and is either considered a polymorphic species or a complex of subspecies, due to its numerous morphological variations. We evaluated CAM plasticity within P. oleracea genotypes since the complexity surrounding this species may be reflected in intraspecific variations in photosynthetic behavior. Eleven subspecies of P. oleracea from distant geographical locations and one cultivar were morphologically and physiologically characterized. C4 and CAM photosynthesis were monitored in plants exposed to well-watered, droughted and rewatered treatments, and data obtained were compared among individual genotypes. All subspecies expressed CAM in a fully-reversible manner. Transcript abundance of C4–CAM signature genes was shown to be a useful indicator of the C4–CAM–C4 switches in all genotypes. C4-related genes were down-regulated and subsequently fully expressed upon drought and rewatering, respectively. CAM-marker genes followed the opposite pattern. A gradient of morphological traits and drought-induced nighttime malate accumulation was observed across genotypes. Therefore, different combinations of CAM expression levels, plant sizes and shapes are available within the P. oleracea complex, which can be a valuable tool in the context of C4/CAM photosynthesis research.
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Affiliation(s)
- Renata Callegari Ferrari
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Bruna Coelho Cruz
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | | | - Thalyson Storl
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Elisa Callegari Ferrari
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Susanna F Boxall
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - James Hartwell
- Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Luciano Freschi
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil.
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10
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Guerrero PC, Majure LC, Cornejo-Romero A, Hernández-Hernández T. Phylogenetic Relationships and Evolutionary Trends in the Cactus Family. J Hered 2020; 110:4-21. [PMID: 30476167 DOI: 10.1093/jhered/esy064] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/21/2018] [Indexed: 12/29/2022] Open
Abstract
Members of the cactus family are keystone species of arid and semiarid biomes in the Americas, as they provide shelter and resources to support other members of ecosystems. Extraordinary examples are the several species of flies of the genus Drosophila that lay eggs and feed in their rotting stems, which provide a model system for studying evolutionary processes. Although there is significant progress in understanding the evolution of Drosophila species, there are gaps in our knowledge about the cactus lineages hosting them. Here, we review the current knowledge about the evolution of Cactaceae, focusing on phylogenetic relationships and trends revealed by the study of DNA sequence data. During the last several decades, the availability of molecular phylogenies has considerably increased our understanding of the relationships, biogeography, and evolution of traits in the family. Remarkably, although succulent cacti have very low growth rates and long generation times, they underwent some of the fastest diversifications observed in the plant kingdom, possibly fostered by strong ecological interactions. We have a better understanding of the reproductive biology, population structure and speciation mechanisms in different clades. The recent publication of complete genomes for some species has revealed the importance of phenomena such as incomplete lineage sorting. Hybridization and polyploidization are common in the family, and have been studied using a variety of phylogenetic methods. We discuss potential future avenues for research in Cactaceae, emphasizing the need of a concerted effort among scientists in the Americas, together with the analyses of data from novel sequencing techniques.
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Affiliation(s)
- Pablo C Guerrero
- Departamento de Botánica, Universidad de Concepción, Chile, Concepción, Chile
| | - Lucas C Majure
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ.,Florida Museum of Natural History, University of Florida, Gainesville, FL
| | - Amelia Cornejo-Romero
- Departamento de Botánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
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11
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Winter K, Sage RF, Edwards EJ, Virgo A, Holtum JAM. Facultative crassulacean acid metabolism in a C3-C4 intermediate. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6571-6579. [PMID: 30820551 PMCID: PMC6883265 DOI: 10.1093/jxb/erz085] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 02/14/2019] [Indexed: 05/27/2023]
Abstract
The Portulacaceae enable the study of the evolutionary relationship between C4 and crassulacean acid metabolism (CAM) photosynthesis. Shoots of well-watered plants of the C3-C4 intermediate species Portulaca cryptopetala Speg. exhibit net uptake of CO2 solely during the light. CO2 fixation is primarily via the C3 pathway as indicated by a strong stimulation of CO2 uptake when shoots were provided with air containing 2% O2. When plants were subjected to water stress, daytime CO2 uptake was reduced and CAM-type net CO2 uptake in the dark occurred. This was accompanied by nocturnal accumulation of acid in both leaves and stems, also a defining characteristic of CAM. Following rewatering, net CO2 uptake in the dark ceased in shoots, as did nocturnal acidification of the leaves and stems. With this unequivocal demonstration of stress-related reversible, i.e. facultative, induction of CAM, P. cryptopetala becomes the first C3-C4 intermediate species reported to exhibit CAM. Portulaca molokiniensis Hobdy, a C4 species, also exhibited CAM only when subjected to water stress. Facultative CAM has now been demonstrated in all investigated species of Portulaca, which are well sampled from across the phylogeny. This strongly suggests that in Portulaca, a lineage in which species engage predominately in C4 photosynthesis, facultative CAM is ancestral to C4. In a broader context, it has now been demonstrated that CAM can co-exist in leaves that exhibit any of the other types of photosynthesis known in terrestrial plants: C3, C4 and C3-C4 intermediate.
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Affiliation(s)
- Klaus Winter
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Aurelio Virgo
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Joseph A M Holtum
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia
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12
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Winter K, Garcia M, Virgo A, Holtum JAM. Operating at the very low end of the crassulacean acid metabolism spectrum: Sesuvium portulacastrum (Aizoaceae). JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6561-6570. [PMID: 30535159 PMCID: PMC6883264 DOI: 10.1093/jxb/ery431] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 11/30/2018] [Indexed: 05/31/2023]
Abstract
Demonstration of crassulacean acid metabolism (CAM) in species with low usage of this system relative to C3-photosynthetic CO2 assimilation can be challenging experimentally but provides crucial information on the early steps of CAM evolution. Here, weakly expressed CAM was detected in the well-known pantropical coastal, leaf-succulent herb Sesuvium portulacastrum, demonstrating that CAM is present in the Sesuvioideae, the only sub-family of the Aizoaceae in which it had not yet been shown conclusively. In outdoor plots in Panama, leaves and stems of S. portulacastrum consistently exhibited a small degree of nocturnal acidification which, in leaves, increased during the dry season. In potted plants, nocturnal acidification was mainly facultative, as levels of acidification increased in a reversible manner following the imposition of short-term water-stress. In drought-stressed plants, nocturnal net CO2 exchange approached the CO2-compensation point, consistent with low rates of CO2 dark fixation sufficient to eliminate respiratory carbon loss. Detection of low-level CAM in S. portulacastrum adds to the growing number of species that cannot be considered C3 plants sensu stricto, although they obtain CO2 principally via the C3 pathway. Knowledge about the presence/absence of low-level CAM is critical when assessing trajectories of CAM evolution in lineages. The genus Sesuvium is of particular interest because it also contains C4 species.
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Affiliation(s)
- Klaus Winter
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Milton Garcia
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Aurelio Virgo
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Joseph A M Holtum
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
- Centre for Tropical Biodiversity and Climate Change, College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
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13
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Edwards EJ. Evolutionary trajectories, accessibility and other metaphors: the case of C 4 and CAM photosynthesis. THE NEW PHYTOLOGIST 2019; 223:1742-1755. [PMID: 30993711 DOI: 10.1111/nph.15851] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/18/2019] [Indexed: 05/24/2023]
Abstract
Are evolutionary outcomes predictable? Adaptations that show repeated evolutionary convergence across the Tree of Life provide a special opportunity to dissect the context surrounding their origins, and identify any commonalities that may predict why certain traits evolved many times in particular clades and yet never evolved in others. The remarkable convergence of C4 and Crassulacean Acid Metabolism (CAM) photosynthesis in vascular plants makes them exceptional model systems for understanding the repeated evolution of complex phenotypes. This review highlights what we have learned about the recurring assembly of C4 and CAM, focusing on the increasingly predictable stepwise evolutionary integration of anatomy and biochemistry. With the caveat that we currently understand C4 evolution better than we do CAM, I propose a general model that explains and unites C4 and CAM evolutionary trajectories. Available data suggest that anatomical modifications are the 'rate-limiting step' in each trajectory, which in large part determines the evolutionary accessibility of both syndromes. The idea that organismal structure exerts a primary influence on innovation is discussed in the context of other systems. Whether the rate-limiting step occurs early or late in the evolutionary assembly of a new phenotype may have profound implications for its distribution across the Tree of Life.
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Affiliation(s)
- Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St, New Haven, CT, 06520-8105, USA
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14
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Hancock LP, Holtum JAM, Edwards EJ. The Evolution of CAM Photosynthesis in Australian Calandrinia Reveals Lability in C3+CAM Phenotypes and a Possible Constraint to the Evolution of Strong CAM. Integr Comp Biol 2019; 59:517-534. [DOI: 10.1093/icb/icz089] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Australian Calandrinia has radiated across the Australian continent during the last 30 Ma, and today inhabits most Australian ecosystems. Given its biogeographic range and reports of facultative Crassulacean acid metabolism (CAM) photosynthesis in multiple species, we hypothesized (1) that CAM would be widespread across Australian Calandrinia and that species, especially those that live in arid regions, would engage in strong CAM, and (2) that Australian Calandrinia would be an important lineage for informing on the CAM evolutionary trajectory. We cultivated 22 Australian Calandrinia species for a drought experiment. Using physiological measurements and δ13C values we characterized photosynthetic mode across these species, mapped the resulting character states onto a phylogeny, and characterized the climatic envelopes of species in their native ranges. Most species primarily utilize C3 photosynthesis, with CAM operating secondarily, often upregulated following drought. Several phylogenetically nested species are C3, indicating evolutionary losses of CAM. No strong CAM was detected in any of the species. Results highlight the limitations of δ13C surveys in detecting C3+CAM phenotypes, and the evolutionary lability of C3+CAM phenotypes. We propose a model of CAM evolution that allows for lability and reversibility among C3+CAM phenotypes and C3 and suggest that an annual life-cycle may preclude the evolution of strong CAM.
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Affiliation(s)
- Lillian P Hancock
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence, RI 02912, USA
- Terrestrial Ecosystems and Climate Change, College of Marine and Environmental Sciences, James Cook University, Townsville, 4811, Queensland, Australia
| | - Joseph A M Holtum
- Terrestrial Ecosystems and Climate Change, College of Marine and Environmental Sciences, James Cook University, Townsville, 4811, Queensland, Australia
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence, RI 02912, USA
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT PO Box 208105, 06520, USA
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15
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Some like it hot: the physiological ecology of C 4 plant evolution. Oecologia 2018; 187:941-966. [PMID: 29955992 DOI: 10.1007/s00442-018-4191-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 06/05/2018] [Indexed: 10/28/2022]
Abstract
The evolution of C4 photosynthesis requires an intermediate phase where photorespiratory glycine produced in the mesophyll cells must flow to the vascular sheath cells for metabolism by glycine decarboxylase. This glycine flux concentrates photorespired CO2 within the sheath cells, allowing it to be efficiently refixed by sheath Rubisco. A modest C4 biochemical cycle is then upregulated, possibly to support the refixation of photorespired ammonia in sheath cells, with subsequent increases in C4 metabolism providing incremental benefits until an optimized C4 pathway is established. 'Why' C4 photosynthesis evolved is largely explained by ancestral C3 species exploiting photorespiratory CO2 to improve carbon gain and thus enhance fitness. While photorespiration depresses C3 performance, it produces a resource (photorespired CO2) that can be exploited to build an evolutionary bridge to C4 photosynthesis. 'Where' C4 evolved is indicated by the habitat of species branching near C3-to-C4 transitions on phylogenetic trees. Consistent with the photorespiratory bridge hypothesis, transitional species show that the large majority of > 60 C4 lineages arose in hot, dry, and/or saline regions where photorespiratory potential is high. 'When' C4 evolved has been clarified by molecular clock analyses using phylogenetic data, coupled with isotopic signatures from fossils. Nearly all C4 lineages arose after 25 Ma when atmospheric CO2 levels had fallen to near current values. This reduction in CO2, coupled with persistent high temperature at low-to-mid-latitudes, met a precondition where photorespiration was elevated, thus facilitating the evolutionary selection pressure that led to C4 photosynthesis.
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16
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Muhaidat R, McKown AD, Al Zoubi M, Bani Domi Z, Otoum O. C 4 photosynthesis and transition of Kranz anatomy in cotyledons and leaves of Tetraena simplex. AMERICAN JOURNAL OF BOTANY 2018; 105:822-835. [PMID: 29791720 DOI: 10.1002/ajb2.1087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 02/22/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Tetraena simplex is an independently evolved C4 species in the Zygophylloideae (Zygophyllaceae) and a characteristic forb of saline flats in hot and sandy desert habitats. During early ontogeny, the species had a morphological shift from planar cotyledons (dorsiventral symmetry) to terete, succulent leaves (radial symmetry). We tested whether this shift had a corresponding change in internal Kranz anatomy and tissue patterning. METHODS For a comprehensive characterization of C4 photosynthesis across early ontogeny in T. simplex, structural and ultrastructural anatomical properties and localization patterns, activities, and immunoblotting of key C4 photosynthetic enzymes were compared in mesophyll and bundle sheath tissues in cotyledons and leaves. KEY RESULTS Cotyledons and leaves possessed different types of Kranz anatomy (atriplicoid type and a "Tetraena" variant of the kochioid type, respectively), reflecting the change in leaf morphology. In bundle sheath cells, key differences in ultrastructural features included increased organelle numbers and chloroplast thylakoid stacking. C4 enzymes had strict tissue-specific localization patterns within bundle sheath and mesophyll cells in both cotyledons and leaves. The decarboxylase NAD-ME maintained the highest activity, increasing from cotyledons to leaves. This classified T. simplex as fully C4 across ontogeny and a strictly NAD-ME biochemical subtype. CONCLUSIONS Tetraena simplex cotyledons and leaves showed differences in Kranz type, with associated progression in ultrastructural features, and differing activities/expression levels of C4 enzymes. Furthermore, leaves characterized a new "Tetraena" variation of the kochioid Kranz anatomy.
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Affiliation(s)
- Riyadh Muhaidat
- Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid, P. O. Box 21163, Jordan
| | - Athena D McKown
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Mazhar Al Zoubi
- Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid, P. O. Box 21163, Jordan
- Department of Basic Sciences, Faculty of Medicine, Yarmouk University, Irbid, P. O. Box 21163, Jordan
| | - Zakariya Bani Domi
- Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid, P. O. Box 21163, Jordan
| | - Osama Otoum
- Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid, P. O. Box 21163, Jordan
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17
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Danderson CA, Downie SR, Hermann M. Rampant polyphyly in the Arracacia clade (Apiaceae) and an assessment of the phylogenetic utility of 20 noncoding plastid loci. Mol Phylogenet Evol 2017; 118:286-305. [PMID: 29017853 DOI: 10.1016/j.ympev.2017.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 10/18/2022]
Abstract
The Arracacia clade (Apiaceae, Apioideae) is a heterogeneous assemblage of 12 genera, comprising 111 known species distributed in high montane temperate and sub-alpine habitats of meso- and South America. Previous studies have indicated that the genera Arracacia, Coulterophytum, and Prionosciadium are polyphyletic, but for the most part relationships among the members of the clade are largely unknown. Initially, cladistic analyses of nrDNA ITS sequences were carried out on 212 accessions (122 taxa), representing 92 species of the Arracacia clade and outgroups from the closely-related páramo genera Cotopaxia, Niphogeton, and Perissocoeleum and members of the Perennial Endemic North American clade and its allies. Using the ITS results to inform sampling of a small subset of taxa, a pilot study examining the phylogenetic utility of 20 noncoding chloroplast loci was subsequently performed to identify those regions most useful at resolving relationships. A cost-benefit analysis determined that five loci (trnQ-5'rps16, trnD-trnT, rpl32-trnL, psbD-trnT, ndhA intron) would maximize resolution and branch support in the clade. Cladistic analyses of four of these loci (trnQ-5'rps16, trnD-trnT, rpl32-trnL, ndhA intron) and the ITS region, separately and combined, revealed that Arracacia, Coaxana, Coulterophytum, Prionosciadium, and Rhodosciadium are each polyphyletic and that Donnellsmithia and Myrrhidendron are each monophyletic. Although most relationships in the Arracacia clade and among the closely-related genera Cotopaxia, Niphogeton, and Perissocoeleum are poorly resolved and supported, ten groups are recognized for future revisionary studies. Polyploidy and rapid species radiation have likely confounded generic circumscriptions and interpretation of relationships.
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Affiliation(s)
- Clark A Danderson
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Stephen R Downie
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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18
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Holtum JAM, Hancock LP, Edwards EJ, Winter K. Optional use of CAM photosynthesis in two C 4 species, Portulaca cyclophylla and Portulaca digyna. JOURNAL OF PLANT PHYSIOLOGY 2017; 214:91-96. [PMID: 28511087 DOI: 10.1016/j.jplph.2017.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 06/07/2023]
Abstract
Low levels of crassulacean acid metabolism (CAM) are demonstrated in two species with C4 photosynthesis, Portulaca cyclophylla and P. digyna. The expression of CAM in P. cyclophylla and P. digyna is facultative, i.e. optional. Well-watered plants did not accumulate acid at night and exhibited gas-exchange patterns consistent with C4 photosynthesis. CAM-type nocturnal acidification was reversible in that it was induced following drought and lost when droughted plants were rewatered. In P. cyclophylla, droughting was accompanied by a small but discernible net uptake of CO2 during the dark, whereas in P. digyna, net CO2 exchange at night approached the CO2 compensation point but did not transition beyond it. This report brings the number of known C4 species with a capacity for expressing CAM to six. All are species of Portulaca. The observation of CAM in P. cyclophylla and P. digyna is the first for species in the opposite-leaved (OL) Portulacelloid-anatomy lineage of Portulaca and for the Australian clade therein. The other four species are within the alternate-leaved (AL) lineage, in the Atriploid-anatomy Oleracea and the Pilosoid-anatomy Pilosa clades. Studies of the evolutionary origins of C4 and CAM in Portulaca will benefit from a more wide-range survey of CAM across its species, particularly in the C3-C4 intermediate-containing Cryptopetala clade.
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Affiliation(s)
- Joseph A M Holtum
- Centre for Tropical Biodiversity and Climate Change, College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Panama.
| | - Lillian P Hancock
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence RI 02912, USA.
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence RI 02912, USA.
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Panama.
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19
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Schüssler C, Freitag H, Koteyeva N, Schmidt D, Edwards G, Voznesenskaya E, Kadereit G. Molecular phylogeny and forms of photosynthesis in tribe Salsoleae (Chenopodiaceae). JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:207-223. [PMID: 28003310 PMCID: PMC5853613 DOI: 10.1093/jxb/erw432] [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: 06/05/2016] [Accepted: 11/04/2016] [Indexed: 05/09/2023]
Abstract
While many C4 lineages have Kranz anatomy around individual veins, Salsoleae have evolved the Salsoloid Kranz anatomy where a continuous dual layer of chlorenchyma cells encloses the vascular and water-storage tissue. With the aim of elucidating the evolution of C4 photosynthesis in Salsoleae, a broadly sampled molecular phylogeny and anatomical survey was conducted, together with biochemical, microscopic, and physiological analyses of selected photosynthetic types. From analyses of photosynthetic phenotypes, a model for evolution of this form of C4 was compared with models for evolution of Kranz anatomy around individual veins. A functionally C3 proto-Kranz phenotype (Proto-Kranz Sympegmoid) and intermediates with a photorespiratory pump (Kranz-like Sympegmoid and Kranz-like Salsoloid types) are considered crucial transitional steps towards C4 development. The molecular phylogeny provides evidence for C3 being the ancestral photosynthetic pathway but there is no phylogenetic evidence for the ancestry of C3-C4 intermediacy with respect to C4 in Salsoleae. Traits considered advantageous in arid conditions, such as annual life form, central sclerenchyma in leaves, and reduction of surface area, evolved repeatedly in Salsoleae. The recurrent evolution of a green stem cortex taking over photosynthesis in C4 clades of Salsoleae concurrent with leaf reduction was probably favoured by the higher productivity of the C4 cycle.
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Affiliation(s)
- Christina Schüssler
- Botany Department, State Museum of Natural History Stuttgart, Rosenstein 1, D-70191 Stuttgart, Germany
- Centre for Organismal Studies Heidelberg, Biodiversity and Plant Systematics, Heidelberg University, D-69120 Heidelberg, Germany
| | - Helmut Freitag
- Institut für Biologie, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany
| | - Nuria Koteyeva
- Laboratory of Anatomy and Morphology, V. L. Komarov Botanical Institute of Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia
| | - Denise Schmidt
- Institute für Allgemeine und Spezielle Botanik und Botanischer Garten der Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
| | - Gerald Edwards
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Elena Voznesenskaya
- Laboratory of Anatomy and Morphology, V. L. Komarov Botanical Institute of Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia
| | - Gudrun Kadereit
- Institute für Allgemeine und Spezielle Botanik und Botanischer Garten der Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
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20
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Sage RF. A portrait of the C4 photosynthetic family on the 50th anniversary of its discovery: species number, evolutionary lineages, and Hall of Fame. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4039-4056. [PMID: 28110278 DOI: 10.1093/jxb/erx005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Fifty years ago, the C4 photosynthetic pathway was first characterized. In the subsequent five decades, much has been learned about C4 plants, such that it is now possible to place nearly all C4 species into their respective evolutionary lineages. Sixty-one independent lineages of C4 photosynthesis are identified, with additional, ancillary C4 origins possible in 12 of these principal lineages. The lineages produced ~8100 C4 species (5044 grasses, 1322 sedges, and 1777 eudicots). Using midpoints of stem and crown node dates in their respective phylogenies, the oldest and most speciose C4 lineage is the grass lineage Chloridoideae, estimated to be near 30 million years old. Most C4 lineages are estimated to be younger than 15 million years. Older C4 lineages tend to be more speciose, while those younger than 7 million years have <43 species each. To further highlight C4 photosynthesis for a 50th anniversary snapshot, a Hall of Fame comprised of the 40 most significant C4 species is presented. Over the next 50 years, preservation of the Earth's C4 diversity is a concern, largely because of habitat loss due to elevated CO2 effects, invasive species, and expanded agricultural activities. Ironically, some members of the C4 Hall of Fame are leading threats to the natural C4 flora due to their association with human activities on landscapes where most C4 plants occur.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5R3C6
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21
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Voznesenskaya EV, Koteyeva NK, Edwards GE, Ocampo G. Unique photosynthetic phenotypes in Portulaca (Portulacaceae): C3-C4 intermediates and NAD-ME C4 species with Pilosoid-type Kranz anatomy. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:225-239. [PMID: 27986845 PMCID: PMC5853368 DOI: 10.1093/jxb/erw393] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/18/2016] [Indexed: 05/24/2023]
Abstract
Portulacaceae is a family that has considerable diversity in photosynthetic phenotypes. It is one of 19 families of terrestrial plants where species having C4 photosynthesis have been found. Most species in Portulaca are in the alternate-leaved (AL) lineage, which includes one clade (Cryptopetala) with taxa lacking C4 photosynthesis and three clades having C4 species (Oleracea, Umbraticola and Pilosa). All three species in the Cryptopetala clade lack Kranz anatomy, the leaves have C3-like carbon isotope composition and they have low levels of C4 cycle enzymes. Anatomical, biochemical and physiological analyses show they are all C3-C4 intermediates. They have intermediate CO2 compensation points, enrichment of organelles in the centripetal position in bundle sheath (BS) cells, with selective localization of glycine decarboxylase in BS mitochondria. In the three C4 clades there are differences in Kranz anatomy types and form of malic enzyme (ME) reported to function in C4 (NAD-ME versus NADP-ME): Oleracea (Atriplicoid, NAD-ME), Umbraticola (Atriplicoid, NADP-ME) and Pilosa (Pilosoid, NADP-ME). Structural and biochemical analyses were performed on Pilosa clade representatives having Pilosoid-type leaf anatomy with Kranz tissue enclosing individual peripheral vascular bundles and water storage in the center of the leaf. In this clade, all species except P. elatior are NADP-ME-type C4 species with grana-deficient BS chloroplasts and grana-enriched M chloroplasts. Surprisingly, P. elatior has BS chloroplasts enriched in grana and NAD-ME-type photosynthesis. The results suggest photosynthetic phenotypes were probably derived from an ancestor with NADP-ME-type C4, with two independent switches to NAD-ME type.
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Affiliation(s)
- Elena V Voznesenskaya
- Laboratory of Anatomy and Morphology, VL Komarov Botanical Institute of Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia
| | - Nuria K Koteyeva
- Laboratory of Anatomy and Morphology, VL Komarov Botanical Institute of Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia
| | - Gerald E Edwards
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Gilberto Ocampo
- Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
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22
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Sage RF, Sultmanis S. Why are there no C 4 forests? JOURNAL OF PLANT PHYSIOLOGY 2016; 203:55-68. [PMID: 27481816 DOI: 10.1016/j.jplph.2016.06.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/13/2016] [Accepted: 06/15/2016] [Indexed: 05/22/2023]
Abstract
C4 photosynthesis is absent from the arborescent life form, with the exception of seven Hawaiian Euphorbia species and a few desert shrubs that become arborescent with age. As a consequence, wherever C3 trees can establish, their height advantage enables them to outcompete low stature C4 vegetation. Had C4 photosynthesis been able to evolve in an arborescent life form, forest cover (by C4 trees) could have been much more extensive than today, with significant consequences for the biosphere. Here, we address why there are so few C4 trees. Physiological explanations associated with low light performance of C4 photosynthesis are not supported, because C4 shade-tolerant species exhibit similar performance as shade-tolerant C3 species in terms of quantum yield, steady-state photosynthetic and use of sunflecks. Hence, hypothetical C4 trees could occur in the regeneration niche of forests. Constraints associated with the evolutionary history of the C4 lineages are more plausible. Most C4 species are grasses and sedges, which lack meristems needed for arborescence, while most C4 eudicots are highly specialized for harsh (arid, saline, hot) or disturbed habitats where arborescence may be maladapted. Most C4 eudicot clades are also young, and have not had sufficient time to radiate beyond the extreme environments where C4 evolution is favored. In the case of the Hawaiian Euphorbia species, they belong to one of the oldest and most diverse C4 lineages, which primed this group to evolve arborescence in a low-competition environment that appeared on the remote Hawaiian Islands.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada.
| | - Stefanie Sultmanis
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada
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23
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Sage RF. A portrait of the C4 photosynthetic family on the 50th anniversary of its discovery: species number, evolutionary lineages, and Hall of Fame. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4039-56. [PMID: 27053721 DOI: 10.1093/jxb/erw156] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Fifty years ago, the C4 photosynthetic pathway was first characterized. In the subsequent five decades, much has been learned about C4 plants, such that it is now possible to place nearly all C4 species into their respective evolutionary lineages. Sixty-one independent lineages of C4 photosynthesis are identified, with additional, ancillary C4 origins possible in 12 of these principal lineages. The lineages produced ~8100 C4 species (5044 grasses, 1322 sedges, and 1777 eudicots). Using midpoints of stem and crown node dates in their respective phylogenies, the oldest and most speciose C4 lineage is the grass lineage Chloridoideae, estimated to be near 30 million years old. Most C4 lineages are estimated to be younger than 15 million years. Older C4 lineages tend to be more speciose, while those younger than 7 million years have <43 species each. To further highlight C4 photosynthesis for a 50th anniversary snapshot, a Hall of Fame comprised of the 40 most significant C4 species is presented. Over the next 50 years, preservation of the Earth's C4 diversity is a concern, largely because of habitat loss due to elevated CO2 effects, invasive species, and expanded agricultural activities. Ironically, some members of the C4 Hall of Fame are leading threats to the natural C4 flora due to their association with human activities on landscapes where most C4 plants occur.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5R3C6
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24
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Heckmann D. C4 photosynthesis evolution: the conditional Mt. Fuji. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:149-54. [PMID: 27153468 DOI: 10.1016/j.pbi.2016.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/04/2016] [Accepted: 04/21/2016] [Indexed: 05/09/2023]
Abstract
C4 photosynthesis implements a biochemical carbon pump to suppress photorespiration. While this mechanism allows for increased photosynthetic efficiency, it requires the ancestral C3 state to be modified in terms of leaf anatomy, expression of metabolic genes, and enzyme kinetics. Despite the complexity of the C4 syndrome, it evolved in more than 60 independent lineages. Because the phylogenetic distribution of these origins appears to be non-random, enabling factors that are initially unrelated to C4 photosynthesis are assumed to be acting in certain C3 lineages. In recent years, substantial progress has been made on firstly, the nature of enabling events and finally, quantitative models of C4 evolution that are based on C3-C4 intermediate species. I discuss the synthesis of these approaches as a consensus trajectory towards C4 photosynthesis and hypothesize on the effect of enabling factors on the fitness landscape of C4 evolution. A complete understanding of these mechanisms will require both further experimental studies and improved quantitative models of leaf physiology.
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Affiliation(s)
- David Heckmann
- Heinrich Heine University, Institute for Computer Science, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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25
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Lauterbach M, van der Merwe PDW, Keßler L, Pirie MD, Bellstedt DU, Kadereit G. Evolution of leaf anatomy in arid environments – A case study in southern African Tetraena and Roepera (Zygophyllaceae). Mol Phylogenet Evol 2016; 97:129-144. [DOI: 10.1016/j.ympev.2016.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 01/05/2016] [Accepted: 01/06/2016] [Indexed: 12/28/2022]
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Sage RF, Stata M. Photosynthetic diversity meets biodiversity: the C4 plant example. JOURNAL OF PLANT PHYSIOLOGY 2015; 172:104-19. [PMID: 25264020 DOI: 10.1016/j.jplph.2014.07.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/02/2014] [Accepted: 07/02/2014] [Indexed: 05/16/2023]
Abstract
Physiological diversification reflects adaptation for specific environmental challenges. As the major physiological process that provides plants with carbon and energy, photosynthesis is under strong evolutionary selection that gives rise to variability in nearly all parts of the photosynthetic apparatus. Here, we discuss how plants, notably those using C4 photosynthesis, diversified in response to environmental challenges imposed by declining atmospheric CO2 content in recent geological time. This reduction in atmospheric CO2 increases the rate of photorespiration and reduces photosynthetic efficiency. While plants have evolved numerous mechanisms to compensate for low CO2, the most effective are the carbon concentration mechanisms of C4, C2, and CAM photosynthesis; and the pumping of dissolved inorganic carbon, mainly by algae. C4 photosynthesis enables plants to dominate warm, dry and often salinized habitats, and to colonize areas that are too stressful for most plant groups. Because C4 lineages generally lack arborescence, they cannot form forests. Hence, where they predominate, C4 plants create a different landscape than would occur if C3 plants were to predominate. These landscapes (mostly grasslands and savannahs) present unique selection environments that promoted the diversification of animal guilds able to graze upon the C4 vegetation. Thus, the rise of C4 photosynthesis has made a significant contribution to the origin of numerous biomes in the modern biosphere.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S3B2.
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S3B2
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Sage RF, Khoshravesh R, Sage TL. From proto-Kranz to C4 Kranz: building the bridge to C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3341-56. [PMID: 24803502 DOI: 10.1093/jxb/eru180] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In this review, we examine how the specialized "Kranz" anatomy of C4 photosynthesis evolved from C3 ancestors. Kranz anatomy refers to the wreath-like structural traits that compartmentalize the biochemistry of C4 photosynthesis and enables the concentration of CO2 around Rubisco. A simplified version of Kranz anatomy is also present in the species that utilize C2 photosynthesis, where a photorespiratory glycine shuttle concentrates CO2 into an inner bundle-sheath-like compartment surrounding the vascular tissue. C2 Kranz is considered to be an intermediate stage in the evolutionary development of C4 Kranz, based on the intermediate branching position of C2 species in 14 evolutionary lineages of C4 photosynthesis. In the best-supported model of C4 evolution, Kranz anatomy in C2 species evolved from C3 ancestors with enlarged bundle sheath cells and high vein density. Four independent lineages have been identified where C3 sister species of C2 plants exhibit an increase in organelle numbers in the bundle sheath and enlarged bundle sheath cells. Notably, in all of these species, there is a pronounced shift of mitochondria to the inner bundle sheath wall, forming an incipient version of the C2 type of Kranz anatomy. This incipient version of C2 Kranz anatomy is termed proto-Kranz, and is proposed to scavenge photorespiratory CO2. By doing so, it may provide fitness benefits in hot environments, and thus represent a critical first stage of the evolution of both the C2 and C4 forms of Kranz anatomy.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, On M5S3B2 Canada
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, On M5S3B2 Canada
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, 25 Willcocks Street, Toronto, On M5S3B2 Canada
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Lundgren MR, Osborne CP, Christin PA. Deconstructing Kranz anatomy to understand C4 evolution. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3357-69. [PMID: 24799561 DOI: 10.1093/jxb/eru186] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
C4 photosynthesis is a complex physiological adaptation that confers greater productivity than the ancestral C3 photosynthetic type in environments where photorespiration is high. It evolved in multiple lineages through the coordination of anatomical and biochemical components, which concentrate CO2 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most C4 plants, the CO2-concentrating mechanism is achieved via the confinement of Rubisco to bundle-sheath cells, into which CO2 is biochemically pumped from surrounding mesophyll cells. The C4 biochemical pathway relies on a specific suite of leaf functional properties, often referred to as Kranz anatomy. These include the existence of discrete compartments differentially connected to the atmosphere, a close contact between these compartments, and a relatively large compartment to host the Calvin cycle. In this review, we use a quantitative dataset for grasses (Poaceae) and examples from other groups to isolate the changes in anatomical characteristics that generate these functional properties, including changes in the size, number, and distribution of different cell types. These underlying anatomical characteristics vary among C4 origins, as similar functions emerged via different modifications of anatomical characteristics. In addition, the quantitative characteristics of leaves all vary continuously across C3 and C4 taxa, resulting in C4-like values in some C3 taxa. These observations suggest that the evolution of C4-suitable anatomy might require relatively few changes in plant lineages with anatomical predispositions. Furthermore, the distribution of anatomical traits across C3 and C4 taxa has important implications for the functional diversity observed among C4 lineages and for the approaches used to identify genetic determinants of C4 anatomy.
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Affiliation(s)
- Marjorie R Lundgren
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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Christin PA, Arakaki M, Osborne CP, Bräutigam A, Sage RF, Hibberd JM, Kelly S, Covshoff S, Wong GKS, Hancock L, Edwards EJ. Shared origins of a key enzyme during the evolution of C4 and CAM metabolism. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3609-21. [PMID: 24638902 PMCID: PMC4085957 DOI: 10.1093/jxb/eru087] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
CAM and C4 photosynthesis are two key plant adaptations that have evolved independently multiple times, and are especially prevalent in particular groups of plants, including the Caryophyllales. We investigate the origin of photosynthetic PEPC, a key enzyme of both the CAM and C4 pathways. We combine phylogenetic analyses of genes encoding PEPC with analyses of RNA sequence data of Portulaca, the only plants known to perform both CAM and C4 photosynthesis. Three distinct gene lineages encoding PEPC exist in eudicots (namely ppc-1E1, ppc-1E2 and ppc-2), one of which (ppc-1E1) was recurrently recruited for use in both CAM and C4 photosynthesis within the Caryophyllales. This gene is present in multiple copies in the cacti and relatives, including Portulaca. The PEPC involved in the CAM and C4 cycles of Portulaca are encoded by closely related yet distinct genes. The CAM-specific gene is similar to genes from related CAM taxa, suggesting that CAM has evolved before C4 in these species. The similar origin of PEPC and other genes involved in the CAM and C4 cycles highlights the shared early steps of evolutionary trajectories towards CAM and C4, which probably diverged irreversibly only during the optimization of CAM and C4 phenotypes.
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Affiliation(s)
- Pascal-Antoine Christin
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK Department of Ecology and Evolutionary Biology, Brown University, 80 Waterman St., Providence, RI 02912, USA
| | - Monica Arakaki
- Department of Ecology and Evolutionary Biology, Brown University, 80 Waterman St., Providence, RI 02912, USA Departamento de Botánica, Facultad de Ciencias Biológicas and Museo de Historia Natural - UNMSM, Av. Arenales 1256, Lima 11, Peru
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Andrea Bräutigam
- Institute of Plant Biochemistry, Heinrich-Heine University, 40225 Duesseldorf, Germany
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Gane Ka-Shu Wong
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2E1, Canada BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, China
| | - Lillian Hancock
- Department of Ecology and Evolutionary Biology, Brown University, 80 Waterman St., Providence, RI 02912, USA
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Brown University, 80 Waterman St., Providence, RI 02912, USA
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