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Perron N, Kirst M, Chen S. Bringing CAM photosynthesis to the table: Paving the way for resilient and productive agricultural systems in a changing climate. PLANT COMMUNICATIONS 2024; 5:100772. [PMID: 37990498 PMCID: PMC10943566 DOI: 10.1016/j.xplc.2023.100772] [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: 06/20/2023] [Revised: 07/27/2023] [Accepted: 11/20/2023] [Indexed: 11/23/2023]
Abstract
Modern agricultural systems are directly threatened by global climate change and the resulting freshwater crisis. A considerable challenge in the coming years will be to develop crops that can cope with the consequences of declining freshwater resources and changing temperatures. One approach to meeting this challenge may lie in our understanding of plant photosynthetic adaptations and water use efficiency. Plants from various taxa have evolved crassulacean acid metabolism (CAM), a water-conserving adaptation of photosynthetic carbon dioxide fixation that enables plants to thrive under semi-arid or seasonally drought-prone conditions. Although past research on CAM has led to a better understanding of the inner workings of plant resilience and adaptation to stress, successful introduction of this pathway into C3 or C4 plants has not been reported. The recent revolution in molecular, systems, and synthetic biology, as well as innovations in high-throughput data generation and mining, creates new opportunities to uncover the minimum genetic tool kit required to introduce CAM traits into drought-sensitive crops. Here, we propose four complementary research avenues to uncover this tool kit. First, genomes and computational methods should be used to improve understanding of the nature of variations that drive CAM evolution. Second, single-cell 'omics technologies offer the possibility for in-depth characterization of the mechanisms that trigger environmentally controlled CAM induction. Third, the rapid increase in new 'omics data enables a comprehensive, multimodal exploration of CAM. Finally, the expansion of functional genomics methods is paving the way for integration of CAM into farming systems.
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Affiliation(s)
- Noé Perron
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32608, USA
| | - Matias Kirst
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32608, USA; School of Forest, Fisheries and Geomatics Sciences, University of Florida, Gainesville, FL 32603, USA.
| | - Sixue Chen
- Department of Biology, University of Mississippi, Oxford, MS 38677-1848, USA.
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2
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Yamaga-Hatakeyama Y, Okutani M, Hatakeyama Y, Yabiku T, Yukawa T, Ueno O. Photosynthesis and leaf structure of F1 hybrids between Cymbidium ensifolium (C3) and C. bicolor subsp. pubescens (CAM). ANNALS OF BOTANY 2023; 132:895-907. [PMID: 36579478 PMCID: PMC10799985 DOI: 10.1093/aob/mcac157] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/17/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS The introduction of crassulacean acid metabolism (CAM) into C3 crops has been considered as a means of improving water-use efficiency. In this study, we investigated photosynthetic and leaf structural traits in F1 hybrids between Cymbidium ensifolium (female C3 parent) and C. bicolor subsp. pubescens (male CAM parent) of the Orchidaceae. METHODS Seven F1 hybrids produced through artificial pollination and in vitro culture were grown in a greenhouse with the parent plants. Structural, biochemical and physiological traits involved in CAM in their leaves were investigated. KEY RESULTS Cymbidium ensifolium accumulated very low levels of malate without diel fluctuation, whereas C. bicolor subsp. pubescens showed nocturnal accumulation and diurnal consumption of malate. The F1s also accumulated malate at night, but much less than C. bicolor subsp. pubescens. This feature was consistent with low nocturnal fixation of atmospheric CO2 in the F1s. The δ13C values of the F1s were intermediate between those of the parents. Leaf thickness was thicker in C. bicolor subsp. pubescens than in C. ensifolium, and those of the F1s were more similar to that of C. ensifolium. This was due to the difference in mesophyll cell size. The chloroplast coverage of mesophyll cell perimeter adjacent to intercellular air spaces of C. bicolor subsp. pubescens was lower than that of C. ensifolium, and that of the F1s was intermediate between them. Interestingly, one F1 had structural and physiological traits more similar to those of C. bicolor subsp. pubescens than the other F1s. Nevertheless, all F1s contained intermediate levels of phosphoenolpyruvate carboxylase but as much pyruvate, Pi dikinase as C. bicolor subsp. pubescens. CONCLUSIONS CAM traits were intricately inherited in the F1 hybrids, the level of CAM expression varied widely among F1 plants, and the CAM traits examined were not necessarily co-ordinately transmitted to the F1s.
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Affiliation(s)
| | - Masamitsu Okutani
- School of Agriculture, Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yuto Hatakeyama
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Takayuki Yabiku
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tomohisa Yukawa
- Tsukuba Botanical Garden, National Museum of Nature and Science, Tsukuba, Ibaraki 305-0005, Japan
| | - Osamu Ueno
- Faculty of Agriculture, Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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3
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Leverett A, Borland AM, Inge EJ, Hartzell S. Low internal air space in plants with crassulacean acid metabolism may be an anatomical spandrel. ANNALS OF BOTANY 2023; 132:811-817. [PMID: 37622678 PMCID: PMC10799988 DOI: 10.1093/aob/mcad109] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/19/2023] [Accepted: 08/17/2023] [Indexed: 08/26/2023]
Abstract
Crassulacean acid metabolism (CAM) is a photosynthetic adaptation found in at least 38 plant families. Typically, the anatomy of CAM plants is characterized by large photosynthetic cells and a low percentage of leaf volume consisting of internal air space (% IAS). It has been suggested that reduced mesophyll conductance (gm) arising from low % IAS benefits CAM plants by preventing the movement of CO2 out of cells and ultimately minimizing leakage of CO2 from leaves into the atmosphere during day-time decarboxylation. Here, we propose that low % IAS does not provide any adaptive benefit to CAM plants, because stomatal closure during phase III of CAM will result in internal concentrations of CO2 becoming saturated, meaning low gm will not have any meaningful impact on the flux of gases within leaves. We suggest that low % IAS is more likely an indirect consequence of maximizing the cellular volume within a leaf, to provide space for the overnight storage of malic acid during the CAM cycle.
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Affiliation(s)
- Alistair Leverett
- School of Life Sciences, University of Essex, Wivenhoe Campus, Essex, CO4 3SQ, UK
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Anne M Borland
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Emma J Inge
- School of Life Sciences, University of Essex, Wivenhoe Campus, Essex, CO4 3SQ, UK
| | - Samantha Hartzell
- Department of Civil and Environmental Engineering, Portland State University, 1930 SW 124 Ave., Portland, OR, USA
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4
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Luján M, Leverett A, Winter K. Forty years of research into crassulacean acid metabolism in the genus Clusia: anatomy, ecophysiology and evolution. ANNALS OF BOTANY 2023; 132:739-752. [PMID: 36891814 PMCID: PMC10799992 DOI: 10.1093/aob/mcad039] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/21/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Clusia is the only genus containing dicotyledonous trees with a capacity to perform crassulacean acid metabolism (CAM). Since the discovery of CAM in Clusia 40 years ago, several studies have highlighted the extraordinary plasticity and diversity of life forms, morphology and photosynthetic physiology of this genus. In this review, we revisit aspects of CAM photosynthesis in Clusia and hypothesize about the timing, the environmental conditions and potential anatomical characteristics that led to the evolution of CAM in the group. We discuss the role of physiological plasticity in influencing species distribution and ecological amplitude in the group. We also explore patterns of allometry of leaf anatomical traits and their correlations with CAM activity. Finally, we identify opportunities for further research on CAM in Clusia, such as the role of elevated nocturnal accumulation of citric acid, and gene expression in C3-CAM intermediate phenotypes.
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Affiliation(s)
- Manuel Luján
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, UK
| | - Alistair Leverett
- School of Life Sciences, University of Essex, Colchester, Essex CO4 3SQ, UK
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
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5
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Leverett A, Ferguson K, Winter K, Borland AM. Leaf vein density correlates with crassulacean acid metabolism, but not hydraulic capacitance, in the genus Clusia. ANNALS OF BOTANY 2023; 132:801-810. [PMID: 36821473 PMCID: PMC10799986 DOI: 10.1093/aob/mcad035] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/26/2023] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND AIMS Many succulent species are characterized by the presence of Crassulacean acid metabolism (CAM) and/or elevated bulk hydraulic capacitance (CFT). Both CAM and elevated CFT substantially reduce the rate at which water moves through transpiring leaves. However, little is known about how these physiological adaptations are coordinated with leaf vascular architecture. METHODS The genus Clusia contains species spanning the entire C3-CAM continuum, and also is known to have >5-fold interspecific variation in CFT. We used this highly diverse genus to explore how interspecific variation in leaf vein density is coordinated with CAM and CFT. KEY RESULTS We found that constitutive CAM phenotypes were associated with lower vein length per leaf area (VLA) and vein termini density (VTD), compared to C3 or facultative CAM species. However, when vein densities were standardized by leaf thickness, this value was higher in CAM than C3 species, which is probably an adaptation to overcome apoplastic hydraulic resistance in deep chlorenchyma tissue. In contrast, CFT did not correlate with any xylem anatomical trait measured, suggesting CAM has a greater impact on leaf transpiration rates than CFT. CONCLUSIONS Our findings strongly suggest that CAM photosynthesis is coordinated with leaf vein densities. The link between CAM and vascular anatomy will be important to consider when attempting to bioengineer CAM into C3 crops.
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Affiliation(s)
- Alistair Leverett
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
- School of Life Sciences, University of Essex, Colchester Campus, Colchester, CO4 3SQ, UK
| | - Kate Ferguson
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
| | - Anne M Borland
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK
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6
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Heyduk K, McAssey EV, Field R, Leebens-Mack J. The Agavoideae: an emergent model clade for CAM evolutionary biology. ANNALS OF BOTANY 2023; 132:727-737. [PMID: 37191440 PMCID: PMC10799990 DOI: 10.1093/aob/mcad062] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 04/16/2023] [Accepted: 05/15/2023] [Indexed: 05/17/2023]
Abstract
Crassulacean acid metabolism - or CAM photosynthesis - was described in the early to mid-20th century, and our understanding of this metabolic pathway was later expanded upon through detailed biochemical analyses of carbon balance. Soon after, scientists began to study the ecophysiological implications of CAM, and a large part of this early work was conducted in the genus Agave, in the subfamily Agavoideae of the family Asparagaceae. Today, the Agavoideae continues to be important for the study of CAM photosynthesis, from the ecophysiology of CAM species, to the evolution of the CAM phenotype and to the genomics underlying CAM traits. Here we review past and current work on CAM in the Agavoideae, in particular highlighting the work of Park Nobel in Agave, and focusing on the powerful comparative system the Agavoideae has become for studying the origins of CAM. We also highlight new genomics research and the potential for studying intraspecific variation within species of the Agavoideae, particularly species in the genus Yucca. The Agavoideae has served as an important model clade for CAM research for decades, and undoubtedly will continue to help push our understanding of CAM biology and evolution in the future.
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Affiliation(s)
- Karolina Heyduk
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Edward V McAssey
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Richard Field
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | - Jim Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
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7
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Leverett A, Hartzell S, Winter K, Garcia M, Aranda J, Virgo A, Smith A, Focht P, Rasmussen-Arda A, Willats WGT, Cowan-Turner D, Borland AM. Dissecting succulence: Crassulacean acid metabolism and hydraulic capacitance are independent adaptations in Clusia leaves. PLANT, CELL & ENVIRONMENT 2023; 46:1472-1488. [PMID: 36624682 DOI: 10.1111/pce.14539] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/05/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Succulence is found across the world as an adaptation to water-limited niches. The fleshy organs of succulent plants develop via enlarged photosynthetic chlorenchyma and/or achlorophyllous water storage hydrenchyma cells. The precise mechanism by which anatomical traits contribute to drought tolerance is unclear, as the effect of succulence is multifaceted. Large cells are believed to provide space for nocturnal storage of malic acid fixed by crassulacean acid metabolism (CAM), whilst also buffering water potentials by elevating hydraulic capacitance (CFT ). The effect of CAM and elevated CFT on growth and water conservation have not been compared, despite the assumption that these adaptations often occur together. We assessed the relationship between succulent anatomical adaptations, CAM, and CFT , across the genus Clusia. We also simulated the effects of CAM and CFT on growth and water conservation during drought using the Photo3 model. Within Clusia leaves, CAM and CFT are independent traits: CAM requires large palisade chlorenchyma cells, whereas hydrenchyma tissue governs interspecific differences in CFT . In addition, our model suggests that CAM supersedes CFT as a means to maximise CO2 assimilation and minimise transpiration during drought. Our study challenges the assumption that CAM and CFT are mutually dependent traits within succulent leaves.
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Affiliation(s)
- Alistair Leverett
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Samantha Hartzell
- Department of Civil and Environmental Engineering, Portland State University, Portland, Oregon, USA
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Milton Garcia
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Jorge Aranda
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Aurelio Virgo
- Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panama
| | - Abigail Smith
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Paulina Focht
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Adam Rasmussen-Arda
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - William G T Willats
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Daniel Cowan-Turner
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Anne M Borland
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
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8
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Kumar S, Jeevaraj T, Yunus MH, Chakraborty S, Chakraborty N. The plant cytoskeleton takes center stage in abiotic stress responses and resilience. PLANT, CELL & ENVIRONMENT 2023; 46:5-22. [PMID: 36151598 DOI: 10.1111/pce.14450] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Stress resilience behaviours in plants are defensive mechanisms that develop under adverse environmental conditions to promote growth, development and yield. Over the past decades, improving stress resilience, especially in crop species, has been a focus of intense research for global food security and economic growth. Plants have evolved specific mechanisms to sense external stress and transmit information to the cell interior and generate appropriate responses. Plant cytoskeleton, comprising microtubules and actin filaments, takes a center stage in stress-induced signalling pathways, either as a direct target or as a signal transducer. In the past few years, it has become apparent that the function of the plant cytoskeleton and other associated proteins are not merely limited to elementary processes of cell growth and proliferation, but they also function in stress response and resilience. This review summarizes recent advances in the role of plant cytoskeleton and associated proteins in abiotic stress management. We provide a thorough overview of the mechanisms that plant cells employ to withstand different abiotic stimuli such as hypersalinity, dehydration, high temperature and cold, among others. We also discuss the crucial role of the plant cytoskeleton in organellar positioning under the influence of high light intensity.
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Affiliation(s)
- Sunil Kumar
- Stress Biology, National Institute of Plant Genome Research, New Delhi, India
| | - Theboral Jeevaraj
- Stress Biology, National Institute of Plant Genome Research, New Delhi, India
| | - Mohd H Yunus
- Stress Biology, National Institute of Plant Genome Research, New Delhi, India
| | - Subhra Chakraborty
- Stress Biology, National Institute of Plant Genome Research, New Delhi, India
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9
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Grey KA, Foden WB, Midgley GF. Bioclimatic controls of CO2 assimilation near range limits of the CAM succulent tree Aloidendron dichotomum. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7434-7449. [PMID: 36066187 DOI: 10.1093/jxb/erac343] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
Aloidendron dichotomum appears to be undergoing the early stages of a range shift in response to anthropogenic climate change in south-western Africa. High mortality has been recorded in warmer populations, while population expansions have been recorded in cooler poleward parts of its range. This study aimed to determine the key environmental controls on A. dichotomum photosynthesis in areas of population expansion, to inform the potential attribution of directional population expansion to anthropogenic warming. Nocturnal acid accumulation and CO2 assimilation were measured in individuals growing under a range of temperature and watering treatments in a greenhouse experiment. In addition, nocturnal acid accumulation and phosphoenolpyruvate carboxylase activity were quantified in two wild populations at the most southerly and south-easterly range extents. Multiple lines of evidence confirmed that A. dichotomum performs Crassulacean acid metabolism. Total nocturnal acid accumulation was highest at night-time temperatures of ~21.5 °C, regardless of soil water availability, and night-time CO2 assimilation rates increased with leaf temperature, suggesting a causal link to the cool southern range limit. Leaf acidity at the start of the dark period was highly predictive of nocturnal acid accumulation in all individuals, implicating light availability during the day as an important determinant of nocturnal acid accumulation.
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Affiliation(s)
- Kerry-Anne Grey
- Global Change Biology Group, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- School for Climate Studies, Stellenbosch University, Stellenbosch, South Africa
| | - Wendy B Foden
- Global Change Biology Group, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- South African National Parks, Cape Town, South Africa
- Climate Change Specialist Group, Species Survival Commission, International Union for Conservation of Nature, Gland, Switzerland
| | - Guy F Midgley
- Global Change Biology Group, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- School for Climate Studies, Stellenbosch University, Stellenbosch, South Africa
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10
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Reyes-García C, Orellana R, Dzib Ek S, Peniche Aké S, Tamayo-Chim M, Echevarría-Machado I, Carrillo L, Espadas-Manrique C. Weak crassulacean acid metabolism and other xerophytic adaptive traits in the genus Beaucarnea Lem. (Asparagaceae). PHYSIOLOGIA PLANTARUM 2022; 174:e13816. [PMID: 36321977 DOI: 10.1111/ppl.13816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/05/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
The genus Beaucarnea (Asparagaceae) has economic value as an ornamental plant but also has ecological importance. Nonetheless, habitat, physiological traits and growth parameters of this genus remain largely unknown. We characterized the environmental ranges of Beaucarnea inermis, B. gracilis and B. pliabilis; and screened for the presence of physiological adaptations to drought (biomass allocation, presence of crassulacean acid metabolism [CAM] and its effect on plant water use). We performed experiments in 3- and 5-year-old nursery-grown plants of the three species, measured dry mass accumulation in leaves/stems/roots and screened for CAM using gas exchange, titratable acidity and δ13 C. We performed a second experiment on the water and light use responses of B. pliabilis under drought treatment. We found that B. gracilis was limited to xerophytic scrubs (precipitation >400 mm yr-1 ), while B. pliabilis and B. inermis (precipitation >500 and 700 mm year-1 , respectively) inhabited dry forests. Beaucarnea gracilis had the lowest dry mass and allocation to leaves, while B. inermis showed the opposite pattern. Only B. pliabilis exhibited small but significant acid fluctuations, characterized as weak CAM, along with high proline content. Acid concentration contributed in 2.7% of the daily carbon during the wet season but represented most of the carbon in the dry season, under closed stomata and had an important contribution to osmolality. Thus, CAM is described for the first time in the genus Beaucarnea, but was only present in one of three species, warranting exploration of this metabolism in the remaining species of this genus.
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Affiliation(s)
- Casandra Reyes-García
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Roger Orellana
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Susana Dzib Ek
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Stephany Peniche Aké
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Manuela Tamayo-Chim
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | | | - Lilia Carrillo
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
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11
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Heyduk K, McAssey EV, Leebens‐Mack J. Differential timing of gene expression and recruitment in independent origins of CAM in the Agavoideae (Asparagaceae). THE NEW PHYTOLOGIST 2022; 235:2111-2126. [PMID: 35596719 PMCID: PMC9796715 DOI: 10.1111/nph.18267] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Crassulacean acid metabolism (CAM) photosynthesis has evolved repeatedly across the plant tree of life, however our understanding of the genetic convergence across independent origins remains hampered by the lack of comparative studies. Here, we explore gene expression profiles in eight species from the Agavoideae (Asparagaceae) encompassing three independent origins of CAM. Using comparative physiology and transcriptomics, we examined the variable modes of CAM in this subfamily and the changes in gene expression across time of day and between well watered and drought-stressed treatments. We further assessed gene expression and the molecular evolution of genes encoding phosphoenolpyruvate carboxylase (PPC), an enzyme required for primary carbon fixation in CAM. Most time-of-day expression profiles are largely conserved across all eight species and suggest that large perturbations to the central clock are not required for CAM evolution. By contrast, transcriptional response to drought is highly lineage specific. Yucca and Beschorneria have CAM-like expression of PPC2, a copy of PPC that has never been shown to be recruited for CAM in angiosperms. Together the physiological and transcriptomic comparison of closely related C3 and CAM species reveals similar gene expression profiles, with the notable exception of differential recruitment of carboxylase enzymes for CAM function.
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Affiliation(s)
- Karolina Heyduk
- School of Life SciencesUniversity of Hawaiʻi at MānoaHonoluluHI96822USA
- Department of Plant BiologyUniversity of GeorgiaAthensGA30602USA
- Department of Ecology and Evolutionary BiologyYale UniversityNew HavenCT06520USA
| | - Edward V. McAssey
- School of Life SciencesUniversity of Hawaiʻi at MānoaHonoluluHI96822USA
| | - Jim Leebens‐Mack
- Department of Plant BiologyUniversity of GeorgiaAthensGA30602USA
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12
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Heyduk K. Evolution of Crassulacean acid metabolism in response to the environment: past, present, and future. PLANT PHYSIOLOGY 2022; 190:19-30. [PMID: 35748752 PMCID: PMC9434201 DOI: 10.1093/plphys/kiac303] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Crassulacean acid metabolism (CAM) is a mode of photosynthesis that evolved in response to decreasing CO2 levels in the atmosphere some 20 million years ago. An elevated ratio of O2 relative to CO2 caused many plants to face increasing stress from photorespiration, a process exacerbated for plants living under high temperatures or in water-limited environments. Today, our climate is again rapidly changing and plants' ability to cope with and adapt to these novel environments is critical for their success. This review focuses on CAM plant responses to abiotic stressors likely to dominate in our changing climate: increasing CO2 levels, increasing temperatures, and greater variability in drought. Empirical studies that have assessed CAM responses are reviewed, though notably these are concentrated in relatively few CAM lineages. Other aspects of CAM biology, including the effects of abiotic stress on the light reactions and the role of leaf succulence, are also considered in the context of climate change. Finally, more recent studies using genomic techniques are discussed to link physiological changes in CAM plants with the underlying molecular mechanism. Together, the body of work reviewed suggests that CAM plants will continue to thrive in certain environments under elevated CO2. However, how CO2 interacts with other environmental factors, how those interactions affect CAM plants, and whether all CAM plants will be equally affected remain outstanding questions regarding the evolution of CAM on a changing planet.
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Heyduk K, Ray JN, Leebens-Mack J. Leaf anatomy is not correlated to CAM function in a C3+CAM hybrid species, Yucca gloriosa. ANNALS OF BOTANY 2021; 127:437-449. [PMID: 32166326 PMCID: PMC7988526 DOI: 10.1093/aob/mcaa036] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 03/05/2020] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS Crassulacean acid metabolism (CAM) is often considered to be a complex trait, requiring orchestration of leaf anatomy and physiology for optimal performance. However, the observation of trait correlations is based largely on comparisons between C3 and strong CAM species, resulting in a lack of understanding as to how such traits evolve and the level of intraspecific variability for CAM and associated traits. METHODS To understand intraspecific variation for traits underlying CAM and how these traits might assemble over evolutionary time, we conducted detailed time course physiological screens and measured aspects of leaf anatomy in 24 genotypes of a C3+CAM hybrid species, Yucca gloriosa (Asparagaceae). Comparisons were made to Y. gloriosa's progenitor species, Y. filamentosa (C3) and Y. aloifolia (CAM). KEY RESULTS Based on gas exchange and measurement of leaf acids, Y. gloriosa appears to use both C3 and CAM, and varies across genotypes in the degree to which CAM can be upregulated under drought stress. While correlations between leaf anatomy and physiology exist when testing across all three Yucca species, such correlations break down at the species level in Y. gloriosa. CONCLUSIONS The variation in CAM upregulation in Y. gloriosa is a result of its relatively recent hybrid origin. The lack of trait correlations between anatomy and physiology within Y. gloriosa indicate that the evolution of CAM, at least initially, can proceed through a wide combination of anatomical traits, and more favourable combinations are eventually selected for in strong CAM plants.
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Affiliation(s)
- Karolina Heyduk
- School of Life Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
- For correspondence. E-mail
| | - Jeremy N Ray
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | - Jim Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA, USA
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Heyduk K. The genetic control of succulent leaf development. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101978. [PMID: 33454545 DOI: 10.1016/j.pbi.2020.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/09/2020] [Accepted: 11/14/2020] [Indexed: 05/25/2023]
Abstract
Succulent leaves have long intrigued biologists; much research has been done to define succulence, understand the evolutionary trajectory and implications of leaf succulence, and contextualize the ecological importance of water storage for plants inhabiting dry habitats, particularly those using CAM photosynthesis. Surprisingly little is understood about the molecular regulation of leaf succulence, despite advances in our understanding of the molecular foundation of leaf architecture in model systems. Moreover, leaf succulence is a drought avoidance trait, one that has yet to be fully used for crop improvement. Here, connections between disparate literatures are highlighted: research on the regulation of cell size, the determination of vascular patterning, and water transport between cells have direct implications for our understanding of leaf succulence. Connecting functional genomics of leaf patterning with knowledge of the evolution and ecology of succulent species will guide future research on the determination and maintenance of leaf succulence.
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Affiliation(s)
- Karolina Heyduk
- University of Hawai'i at Mānoa, 1800 East West Rd., Honolulu, HI 96822, USA.
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15
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Heyduk K, McAssey EV, Grimwood J, Shu S, Schmutz J, McKain MR, Leebens-Mack J. Hybridization History and Repetitive Element Content in the Genome of a Homoploid Hybrid, Yucca gloriosa (Asparagaceae). FRONTIERS IN PLANT SCIENCE 2021; 11:573767. [PMID: 33519836 PMCID: PMC7843428 DOI: 10.3389/fpls.2020.573767] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/17/2020] [Indexed: 05/23/2023]
Abstract
Hybridization in plants results in phenotypic and genotypic perturbations that can have dramatic effects on hybrid physiology, ecology, and overall fitness. Hybridization can also perturb epigenetic control of transposable elements, resulting in their proliferation. Understanding the mechanisms that maintain genomic integrity after hybridization is often confounded by changes in ploidy that occur in hybrid plant species. Homoploid hybrid species, which have no change in chromosome number relative to their parents, offer an opportunity to study the genomic consequences of hybridization in the absence of change in ploidy. Yucca gloriosa (Asparagaceae) is a young homoploid hybrid species, resulting from a cross between Yucca aloifolia and Yucca filamentosa. Previous analyses of ∼11 kb of the chloroplast genome and nuclear-encoded microsatellites implicated a single Y. aloifolia genotype as the maternal parent of Y. gloriosa. Using whole genome resequencing, we assembled chloroplast genomes from 41 accessions of all three species to re-assess the hybrid origins of Y. gloriosa. We further used re-sequencing data to annotate transposon abundance in the three species and mRNA-seq to analyze transcription of transposons. The chloroplast phylogeny and haplotype analysis suggest multiple hybridization events contributing to the origin of Y. gloriosa, with both parental species acting as the maternal donor. Transposon abundance at the superfamily level was significantly different between the three species; the hybrid was frequently intermediate to the parental species in TE superfamily abundance or appeared more similar to one or the other parent. In only one case-Copia LTR transposons-did Y. gloriosa have a significantly higher abundance relative to either parent. Expression patterns across the three species showed little increased transcriptional activity of transposons, suggesting that either no transposon release occurred in Y. gloriosa upon hybridization, or that any transposons that were activated via hybridization were rapidly silenced. The identification and quantification of transposon families paired with expression evidence paves the way for additional work seeking to link epigenetics with the important trait variation seen in this homoploid hybrid system.
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Affiliation(s)
- Karolina Heyduk
- School of Life Sciences, University of Hawai’i at Mānoa, Honolulu, HI, United States
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States
| | - Edward V. McAssey
- School of Life Sciences, University of Hawai’i at Mānoa, Honolulu, HI, United States
- Department of Biological Sciences, Quinnipiac University, Hamden, CT, United States
- Department of Biology and Environmental Science, University of New Haven, West Haven, CT, United States
| | - Jane Grimwood
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States
| | - Shengqiang Shu
- Lawrence Berkeley National Laboratory, US Department of Energy Joint Genome Institute, Berkeley, CA, United States
| | - Jeremy Schmutz
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States
- Lawrence Berkeley National Laboratory, US Department of Energy Joint Genome Institute, Berkeley, CA, United States
| | - Michael R. McKain
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States
| | - Jim Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA, United States
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16
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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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Herrera A. Are thick leaves, large mesophyll cells and small intercellular air spaces requisites for CAM? ANNALS OF BOTANY 2020; 125:859-868. [PMID: 31970387 PMCID: PMC7218806 DOI: 10.1093/aob/mcaa008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/21/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS It is commonly accepted that the leaf of a crassulacean acid metabolism (CAM) plant is thick, with large mesophyll cells and vacuoles that can accommodate the malic acid produced during the night. The link between mesophyll characteristics and CAM mode, whether obligate or C3/CAM, was evaluated. METHODS Published values of the carbon isotopic ratio (δ 13C) as an indicator of CAM, leaf thickness, leaf micrographs and other evidence of CAM operation were used to correlate cell density, cell area, the proportion of intercellular space in the mesophyll (IAS) and the length of cell wall facing the intercellular air spaces (Lmes/A) with CAM mode. KEY RESULTS Based on 81 species and relatively unrelated families (15) belonging to nine orders, neither leaf thickness nor mesophyll traits helped explain the degree of CAM expression. A strong correlation was found between leaf thickness and δ 13C in some species of Crassulaceae and between leaf thickness and nocturnal acid accumulation in a few obligate CAM species of Bromeliaceae but, when all 81 species were pooled together, no significant changes with δ 13C were observed in cell density, cell area, IAS or Lmes/A. CONCLUSIONS An influence of phylogeny on leaf anatomy was evidenced in a few cases but this precluded generalization for widely separate taxa containing CAM species. The possible relationships between leaf anatomy and CAM mode should be interpreted cautiously.
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Affiliation(s)
- Ana Herrera
- Centro de Botánica Tropical, Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, Venezuela
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18
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Sara HC, René GH, Rosa UC, Angela KG, Clelia DLP. Agave angustifolia albino plantlets lose stomatal physiology function by changing the development of the stomatal complex due to a molecular disruption. Mol Genet Genomics 2020; 295:787-805. [PMID: 31925511 DOI: 10.1007/s00438-019-01643-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/24/2019] [Indexed: 12/31/2022]
Abstract
Stomatal development is regulated by signaling pathways that function in multiple cellular programs, including cell fate and cell division. However, recent studies suggest that molecular signals are affected by CO2 concentration, light intensity, and water pressure deficit, thereby modifying distribution patterns and stomatic density and likely other foliar features as well. Here, we show that in addition to lacking chloroplasts, the albino somaclonal variants of Agave angustifolia Haw present an irregular epidermal development and morphological abnormalities of the stomatal complex, affecting the link between the stomatal conductance, transpiration and photosynthesis, as well as the development of the stoma in the upper part of the leaves. In addition, we show that changes in the transcriptional levels of SPEECHLESS (SPCH), TOO MANY MOUTHS (TMM), MITOGEN-ACTIVATED PROTEIN KINASE 4 and 6 (MAPK4 and MAPK6) and FOUR LIPS (FLP), all from the meristematic tissue and leaf, differentially modulate the stomatal function between the green, variegated and albino in vitro plantlets of A. angustifolia. Likewise, we highlight the conservation of microRNAs miR166 and miR824 as part of the regulation of AGAMOUS-LIKE16 (AGL16), recently associated with the control of cell divisions that regulate the development of the stomatal complex. We propose that molecular alterations happening in albino cells formed from the meristematic base can lead to different anomalies during the transition and specification of the stomatal cell state in leaf development of albino plantlets. We conclude that the molecular alterations in the meristematic cells in albino plants might be the main variable associated with stoma distribution in this phenotype.
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Affiliation(s)
- Hernández-Castellano Sara
- Centro de Investigación Científica de Yucatán A.C., Unidad de Biotecnología, Calle 43 N°130 x 32 y 34, Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - Garruña-Hernández René
- CONACYT-Instituto Tecnológico de Conkal, Avenida Tecnológico s/n Conkal, 97345, Mérida, Yucatán, Mexico
| | - Us-Camas Rosa
- Centro de Investigación Científica de Yucatán A.C., Unidad de Biotecnología, Calle 43 N°130 x 32 y 34, Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - Kú-Gonzalez Angela
- Centro de Investigación Científica de Yucatán A.C., Unidad de Bioquímica y Biología Molecular de Plantas, Calle 43 N° 130 x 32 y 34, Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - De-la-Peña Clelia
- Centro de Investigación Científica de Yucatán A.C., Unidad de Biotecnología, Calle 43 N°130 x 32 y 34, Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico.
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19
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Heyduk K, Ray JN, Ayyampalayam S, Moledina N, Borland A, Harding SA, Tsai CJ, Leebens-Mack J. Shared expression of crassulacean acid metabolism (CAM) genes pre-dates the origin of CAM in the genus Yucca. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6597-6609. [PMID: 30870557 PMCID: PMC6883266 DOI: 10.1093/jxb/erz105] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 02/20/2019] [Indexed: 05/05/2023]
Abstract
Crassulacean acid metabolism (CAM) is a carbon-concentrating mechanism that has evolved numerous times across flowering plants and is thought to be an adaptation to water-limited environments. CAM has been investigated from physiological and biochemical perspectives, but little is known about how plants evolve from C3 to CAM at the genetic or metabolic level. Here we take a comparative approach in analyzing time-course data of C3, CAM, and C3+CAM intermediate Yucca (Asparagaceae) species. RNA samples were collected over a 24 h period from both well-watered and drought-stressed plants, and were clustered based on time-dependent expression patterns. Metabolomic data reveal differences in carbohydrate metabolism and antioxidant response between the CAM and C3 species, suggesting that changes to metabolic pathways are important for CAM evolution and function. However, all three species share expression profiles of canonical CAM pathway genes, regardless of photosynthetic pathway. Despite differences in transcript and metabolite profiles between the C3 and CAM species, shared time-structured expression of CAM genes in both CAM and C3Yucca species suggests that ancestral expression patterns required for CAM may have pre-dated its origin in Yucca.
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Affiliation(s)
- Karolina Heyduk
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | - Jeremy N Ray
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | | | - Nida Moledina
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | - Anne Borland
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, UK
| | - Scott A Harding
- Department of Genetics, University of Georgia, Athens, GA, USA
- Warnell School of Forestry, University of Georgia, Athens, GA, USA
| | - Chung-Jui Tsai
- Department of Genetics, University of Georgia, Athens, GA, USA
- Warnell School of Forestry, University of Georgia, Athens, GA, USA
| | - Jim Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA, USA
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20
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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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21
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Li MH, Liu DK, Zhang GQ, Deng H, Tu XD, Wang Y, Lan SR, Liu ZJ. A perspective on crassulacean acid metabolism photosynthesis evolution of orchids on different continents: Dendrobium as a case study. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6611-6619. [PMID: 31625570 DOI: 10.1093/jxb/erz461] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 10/05/2019] [Indexed: 05/26/2023]
Abstract
Members of the Orchidaceae, one of the largest families of flowering plants, evolved the crassulacean acid metabolism (CAM) photosynthesis strategy. It is thought that CAM triggers adaptive radiation into new niche spaces, yet very little is known about its origin and diversification on different continents. Here, we assess the prevalence of CAM in Dendrobium, which is one of the largest genera of flowering plants and found in a wide range of environments, from the high altitudes of the Himalayas to relatively arid habitats in Australia. Based on phylogenetic time trees, we estimated that CAM, as determined by δ 13C values less negative than -20.0‰, evolved independently at least eight times in Dendrobium. The oldest lineage appeared in the Asian clade during the middle Miocene, indicating the origin of CAM was associated with a pronounced climatic cooling that followed a period of aridity. Divergence of the four CAM lineages in the Asian clade appeared to be earlier than divergence of those in the Australasian clade. However, CAM species in the Asian clade are much less diverse (25.6%) than those in the Australasian clade (57.9%). These findings shed new light on CAM evolutionary history and the aridity levels of the paleoclimate on different continents.
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Affiliation(s)
- Ming-He Li
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ding-Kun Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guo-Qiang Zhang
- Shenzhen Key Laboratory for Orchid Conservation and Utilization, the Orchid Conservation & Research Center of Shenzhen, Shenzhen, China
| | - Hua Deng
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Xiong-De Tu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yan Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Si-Ren Lan
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhong-Jian Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
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22
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Turan S, Kask K, Kanagendran A, Li S, Anni R, Talts E, Rasulov B, Kännaste A, Niinemets Ü. Lethal heat stress-dependent volatile emissions from tobacco leaves: what happens beyond the thermal edge? JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5017-5030. [PMID: 31289830 PMCID: PMC6850906 DOI: 10.1093/jxb/erz255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/20/2019] [Indexed: 05/10/2023]
Abstract
Natural vegetation is predicted to suffer from extreme heat events as a result of global warming. In this study, we focused on the immediate response to heat stress. Photosynthesis and volatile emissions were measured in the leaves of tobacco (Nicotiana tabacum cv. Wisconsin 38) after exposure to heat shock treatments between 46 °C and 55 °C. Exposure to 46 °C decreased photosynthetic carbon assimilation rates (A) by >3-fold. Complete inhibition of A was observed at 49 °C, together with a simultaneous decrease in the maximum quantum efficiency of PSII, measured as the Fv/Fm ratio. A large increase in volatile emissions was observed at 52 °C. Heat stress resulted in only minor effects on the emission of monoterpenes, but volatiles associated with membrane damage such as propanal and (E)-2-hexenal+(Z)-3-hexenol were greatly increased. Heat induced changes in the levels of methanol and 2-ethylfuran that are indicative of modification of cell walls. In addition, the oxidation of metabolites in the volatile profiles was strongly enhanced, suggesting the acceleration of oxidative processes at high temperatures that are beyond the thermal tolerance limit.
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Affiliation(s)
- Satpal Turan
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Kaia Kask
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Arooran Kanagendran
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Shuai Li
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Rinaldo Anni
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Eero Talts
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Bahtijor Rasulov
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Astrid Kännaste
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
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23
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Niechayev NA, Pereira PN, Cushman JC. Understanding trait diversity associated with crassulacean acid metabolism (CAM). CURRENT OPINION IN PLANT BIOLOGY 2019; 49:74-85. [PMID: 31284077 DOI: 10.1016/j.pbi.2019.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/30/2019] [Accepted: 06/04/2019] [Indexed: 06/09/2023]
Abstract
Crassulacean acid metabolism (CAM) is a specialized mode of photosynthesis that exploits a temporal CO2 pump with nocturnal CO2 uptake and concentration to reduce photorespiration, improve water-use efficiency (WUE), and optimize the adaptability of plants to climates with seasonal or intermittent water limitations. CAM plants display a plastic continuum in the extent to which species engage in net nocturnal CO2 uptake that ranges from 0 to 100%. CAM plants also display diverse enzyme and organic acid and carbohydrate storage systems, which likely reflect the multiple, independent evolutionary origins of CAM. CAM is often accompanied by a diverse set of anatomical traits, such as tissue succulence and water-storage and water-capture strategies to attenuate drought. Other co-adaptive traits, such as thick cuticles, epicuticular wax, low stomatal density, high stomatal responsiveness, and shallow rectifier-like roots limit water loss under conditions of water deficit. Recommendations for future research efforts to better explore and understand the diversity of traits associated with CAM and CAM Biodesign efforts are presented.
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Affiliation(s)
- Nicholas A Niechayev
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557-0330, United States
| | - Paula N Pereira
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557-0330, United States
| | - John C Cushman
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557-0330, United States.
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Qian D, Zhang Z, He J, Zhang P, Ou X, Li T, Niu L, Nan Q, Niu Y, He W, An L, Jiang K, Xiang Y. Arabidopsis ADF5 promotes stomatal closure by regulating actin cytoskeleton remodeling in response to ABA and drought stress. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:435-446. [PMID: 30476276 PMCID: PMC6322581 DOI: 10.1093/jxb/ery385] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/01/2018] [Indexed: 05/20/2023]
Abstract
Stomatal movement plays an essential role in plant responses to drought stress, and the actin cytoskeleton and abscisic acid (ABA) are two important components of this process. Little is known about the mechanism underlying actin cytoskeleton remodeling and the dynamic changes occurring during stomatal movement in response to drought stress/ABA signaling. Actin-depolymerizing factors (ADFs) are conserved actin severing/depolymerizing proteins in eukaryotes, and in angiosperms ADFs have evolved actin-bundling activity. Here, we reveal that the transcriptional expression of neofunctionalized Arabidopsis ADF5 was induced by drought stress and ABA treatment. Furthermore, we demonstrated that ADF5 loss-of-function mutations increased water loss from detached leaves, reduced plant survival rates after drought stress, and delayed stomatal closure by regulating actin cytoskeleton remodeling via its F-actin-bundling activity. Biochemical assays revealed that an ABF/AREB transcription factor, DPBF3, could bind to the ADF5 promoter and activate its transcription via the ABA-responsive element core motif ACGT/C. Taken together, our findings indicate that ADF5 participates in drought stress by regulating stomatal closure, and may also serve as a potential downstream target of the drought stress/ABA signaling pathway via members of the ABF/AREB transcription factors family.
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Affiliation(s)
- Dong Qian
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Zhe Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Juanxia He
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Pan Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xiaobin Ou
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Tian Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Lipan Niu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Qiong Nan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Yue Niu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Wenliang He
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Lizhe An
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Kun Jiang
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yun Xiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
- Correspondence:
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Heyduk K, Ray JN, Ayyampalayam S, Leebens-Mack J. Shifts in gene expression profiles are associated with weak and strong Crassulacean acid metabolism. AMERICAN JOURNAL OF BOTANY 2018; 105:587-601. [PMID: 29746718 DOI: 10.1002/ajb2.1017] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 10/19/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY The relative ease of high throughput sequencing is facilitating comprehensive phylogenomic and gene expression studies, even for nonmodel groups. To date, however, these two approaches have not been merged; while phylogenomic methods might use transcriptome sequences to resolve relationships, assessment of gene expression patterns in a phylogenetic context is less common. Here we analyzed both carbon assimilation and gene expression patterns of closely related species within the Agavoideae (Asparagaceae) to elucidate changes in gene expression across weak and strong phenotypes for Crassulacean acid metabolism (CAM). METHODS Gene expression patterns were compared across four genera: Agave (CAM), which is paraphyletic with Polianthes (weak CAM) and Manfreda (CAM), and Beschorneria (weak CAM). RNA-sequencing was paired with measures of gas exchange and titratable acidity. Climate niche space was compared across the four lineages to examine abiotic factors and their correlation to CAM. KEY RESULTS Expression of homologous genes showed both shared and variable patterns in weak and strong CAM species. Network analysis highlights that despite shared expression patterns, highly connected genes differ between weak and strong CAM, implicating shifts in regulatory gene function as key for the evolution of CAM. Variation in carbohydrate metabolism between weak and strong CAM supports the importance of sugar turnovers for CAM physiology. CONCLUSIONS Integration of phylogenetics and RNA-sequencing provides a powerful tool to study the evolution of CAM photosynthesis across closely related but photosynthetically variable species. Our findings regarding shared or shifted gene expression and regulation of CAM via carbohydrate metabolism have important implications for efforts to engineer the CAM pathway into C3 food and biofuel crops.
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Affiliation(s)
- Karolina Heyduk
- Miller Plant Sciences, University of Georgia, 120 Carlton Street, 2502, Athens, Georgia, 30602, USA
| | - Jeremy N Ray
- Miller Plant Sciences, University of Georgia, 120 Carlton Street, 2502, Athens, Georgia, 30602, USA
| | | | - James Leebens-Mack
- Miller Plant Sciences, University of Georgia, 120 Carlton Street, 2502, Athens, Georgia, 30602, USA
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Functional Anatomical Traits of the Photosynthetic Organs of Plants with Crassulacean Acid Metabolism. THE LEAF: A PLATFORM FOR PERFORMING PHOTOSYNTHESIS 2018. [DOI: 10.1007/978-3-319-93594-2_10] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Succulent plants are iconic components of the florae of many terrestrial ecosystems, but despite having caused fascination and prompted investigation for centuries, they still harbour many secrets in terms of physiological function and evolution. Tackling these mysteries is important, as this will not only provide insights into the dynamics and details of the convergent evolution of a major adaptive syndrome, but also inform efforts to conserve endangered biodiversity and utilize the unique physiological characteristics of succulents for biofuel and biomass production. Here I review advances in the phylogeny and organismal biology of succulent plants, and discuss how insights from recent work in the wider fields of plant hydraulics and photosynthetic physiology may relate to succulents. The potential for the exploration of mechanistic relationships between anatomical structure and physiological function to improve our understanding of the constraints that have shaped the evolution of succulence is highlighted. Finally, attention is drawn to how new methodologies and technologies provide exciting opportunities to address the wide range of outstanding questions in succulent plant biology.
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Affiliation(s)
- Jamie Males
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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29
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Evolution of a CAM anatomy predates the origins of Crassulacean acid metabolism in the Agavoideae (Asparagaceae). Mol Phylogenet Evol 2016; 105:102-113. [DOI: 10.1016/j.ympev.2016.08.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 11/20/2022]
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