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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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2
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Ferrari RC, Kawabata AB, Ferreira SS, Hartwell J, Freschi L. A matter of time: regulatory events behind the synchronization of C4 and crassulacean acid metabolism in Portulaca oleracea. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4867-4885. [PMID: 35439821 DOI: 10.1093/jxb/erac163] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
Portulaca species can switch between C4 and crassulacean acid metabolism (CAM) depending on environmental conditions. However, the regulatory mechanisms behind this rare photosynthetic adaptation remain elusive. Using Portulaca oleracea as a model system, here we investigated the involvement of the circadian clock, plant hormones, and transcription factors in coordinating C4 and CAM gene expression. Free-running experiments in constant conditions suggested that C4 and CAM gene expression are intrinsically connected to the circadian clock. Detailed time-course, drought, and rewatering experiments revealed distinct time frames for CAM induction and reversion (days versus hours, respectively), which were accompanied by changes in abscisic acid (ABA) and cytokinin metabolism and signaling. Exogenous ABA and cytokinins were shown to promote and repress CAM expression in P. oleracea, respectively. Moreover, the drought-induced decline in C4 transcript levels was completely recovered upon cytokinin treatment. The ABA-regulated transcription factor genes HB7, NFYA7, NFYC9, TT8, and ARR12 were identified as likely candidate regulators of CAM induction following this approach, whereas NFYC4 and ARR9 were connected to C4 expression patterns. Therefore, we provide insights into the signaling events controlling C4-CAM transitions in response to water availability and over the day/night cycle, highlighting candidate genes for future functional studies in the context of facultative C4-CAM photosynthesis.
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Affiliation(s)
- Renata Callegari Ferrari
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, 05508-090, Brasil
| | - Aline Bastos Kawabata
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, 05508-090, Brasil
| | - Sávio Siqueira Ferreira
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, 05508-090, Brasil
| | - James Hartwell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Luciano Freschi
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, 05508-090, Brasil
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3
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Moseley RC, Motta F, Tuskan GA, Haase SB, Yang X. Inference of Gene Regulatory Network Uncovers the Linkage between Circadian Clock and Crassulacean Acid Metabolism in Kalanchoë fedtschenkoi. Cells 2021; 10:2217. [PMID: 34571864 PMCID: PMC8471846 DOI: 10.3390/cells10092217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 02/01/2023] Open
Abstract
The circadian clock drives time-specific gene expression, enabling biological processes to be temporally controlled. Plants that conduct crassulacean acid metabolism (CAM) photosynthesis represent an interesting case of circadian regulation of gene expression as stomatal movement is temporally inverted relative to stomatal movement in C3 plants. The mechanisms behind how the circadian clock enabled physiological differences at the molecular level is not well understood. Recently, the rescheduling of gene expression was reported as a mechanism to explain how CAM evolved from C3. Therefore, we investigated whether core circadian clock genes in CAM plants were re-phased during evolution, or whether networks of phase-specific genes were simply re-wired to different core clock genes. We identified candidate core clock genes based on gene expression features and then applied the Local Edge Machine (LEM) algorithm to infer regulatory relationships between this new set of core candidates and known core clock genes in Kalanchoë fedtschenkoi. We further inferred stomata-related gene targets for known and candidate core clock genes and constructed a gene regulatory network for core clock and stomata-related genes. Our results provide new insight into the mechanism of circadian control of CAM-related genes in K. fedtschenkoi, facilitating the engineering of CAM machinery into non-CAM plants for sustainable crop production in water-limited environments.
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Affiliation(s)
- Robert C. Moseley
- Department of Biology, Duke University, Durham, NC 27708, USA; (R.C.M.); (S.B.H.)
| | - Francis Motta
- Department of Mathematical Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA;
| | - Gerald A. Tuskan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA;
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Steven B. Haase
- Department of Biology, Duke University, Durham, NC 27708, USA; (R.C.M.); (S.B.H.)
- Department of Medicine, Duke University, Durham, NC 27708, USA
| | - Xiaohan Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA;
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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4
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Hogewoning SW, van den Boogaart SAJ, van Tongerlo E, Trouwborst G. CAM-physiology and carbon gain of the orchid Phalaenopsis in response to light intensity, light integral and CO 2. PLANT, CELL & ENVIRONMENT 2021; 44:762-774. [PMID: 33244775 DOI: 10.1111/pce.13960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 06/11/2023]
Abstract
The regulation of photosynthesis and carbon gain of crassulacean acid metabolism (CAM) plants has not yet been disclosed to the extent of C3-plants. In this study, the tropical epiphyte Phalaenopsis cv. "Sacramento" was subjected to different lighting regimes. Photosynthesis and biochemical measuring techniques were used to address four specific questions: (1) the response of malate decarboxylation to light intensity, (2) the malate carboxylation pathway in phase IV, (3) the response of diel carbon gain to the light integral and (4) the response of diel carbon gain to CO2 . The four CAM-phases were clearly discernable. The length of phase III and the malate decarboxylation rate responded directly to light intensity. In phase IV, CO2 was initially mainly carboxylated via Rubisco. However, at daylength of 16 h, specifically beyond ±12 h, it was mainly phosphoenolpyruvate carboxylase (PEP-C) carboxylating CO2 . Diel carbon gain appeared to be controlled by the light integral during phase III rather than the total daily light integral. Elevated CO2 further enhanced carbon gain both in phase IV and phase I. This establishes that neither malate storage capacity, nor availability of PEP as substrate for nocturnal CO2 carboxylation were limiting factors for carbon gain enhancement. These results advance our understanding of CAM-plants and are also of practical importance for growers.
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Affiliation(s)
| | | | - Evelien van Tongerlo
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University & Research, Wageningen, The Netherlands
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5
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Interaction between the Circadian Clock and Regulators of Heat Stress Responses in Plants. Genes (Basel) 2020; 11:genes11020156. [PMID: 32024106 PMCID: PMC7074488 DOI: 10.3390/genes11020156] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 02/07/2023] Open
Abstract
The circadian clock is found ubiquitously in nature, and helps organisms coordinate internal biological processes with environmental cues that inform the time of the day or year. Both temperature stress and the clock affect many important biological processes in plants. Specifically, clock-controlled gene regulation and growth are impacted by a compromised clock or heat stress. The interactions linking these two regulatory pathways include several rhythmic transcription factors that are important for coordinating the appropriate response to temperature stress. Here we review the current understanding of clock control of the regulators involved in heat stress responses in plants.
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6
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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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8
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Eida AA, Ziegler M, Lafi FF, Michell CT, Voolstra CR, Hirt H, Saad MM. Desert plant bacteria reveal host influence and beneficial plant growth properties. PLoS One 2018; 13:e0208223. [PMID: 30540793 PMCID: PMC6291088 DOI: 10.1371/journal.pone.0208223] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/14/2018] [Indexed: 11/19/2022] Open
Abstract
Deserts, such as those found in Saudi Arabia, are one of the most hostile places for plant growth. However, desert plants are able to impact their surrounding microbial community and select beneficial microbes that promote their growth under these extreme conditions. In this study, we examined the soil, rhizosphere and endosphere bacterial communities of four native desert plants Tribulus terrestris, Zygophyllum simplex, Panicum turgidum and Euphorbia granulata from the Southwest (Jizan region), two of which were also found in the Midwest (Al Wahbah area) of Saudi Arabia. While the rhizosphere bacterial community mostly resembled that of the highly different surrounding soils, the endosphere composition was strongly correlated with its host plant phylogeny. In order to assess whether any of the native bacterial endophytes might have a role in plant growth under extreme conditions, we analyzed the properties of 116 cultured bacterial isolates that represent members of the phyla Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. Our analysis shows that different strains have highly different biochemical properties with respect to nutrient acquisition, hormone production and growth under stress conditions. More importantly, eleven of the isolated strains could confer salinity stress tolerance to the experimental model plant Arabidopsis thaliana suggesting some of these plant-associated bacteria might be useful for improving crop desert agriculture.
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Affiliation(s)
- Abdul Aziz Eida
- Desert Agriculture Initiative, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
| | - Maren Ziegler
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
| | - Feras F. Lafi
- Desert Agriculture Initiative, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
| | - Craig T. Michell
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
| | - Christian R. Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
| | - Heribert Hirt
- Desert Agriculture Initiative, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
- * E-mail:
| | - Maged M. Saad
- Desert Agriculture Initiative, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal, Kingdom of Saudi Arabia
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9
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Yin H, Guo HB, Weston DJ, Borland AM, Ranjan P, Abraham PE, Jawdy SS, Wachira J, Tuskan GA, Tschaplinski TJ, Wullschleger SD, Guo H, Hettich RL, Gross SM, Wang Z, Visel A, Yang X. Diel rewiring and positive selection of ancient plant proteins enabled evolution of CAM photosynthesis in Agave. BMC Genomics 2018; 19:588. [PMID: 30081833 PMCID: PMC6090859 DOI: 10.1186/s12864-018-4964-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 07/26/2018] [Indexed: 12/22/2022] Open
Abstract
Background Crassulacean acid metabolism (CAM) enhances plant water-use efficiency through an inverse day/night pattern of stomatal closure/opening that facilitates nocturnal CO2 uptake. CAM has evolved independently in over 35 plant lineages, accounting for ~ 6% of all higher plants. Agave species are highly heat- and drought-tolerant, and have been domesticated as model CAM crops for beverage, fiber, and biofuel production in semi-arid and arid regions. However, the genomic basis of evolutionary innovation of CAM in genus Agave is largely unknown. Results Using an approach that integrated genomics, gene co-expression networks, comparative genomics and protein structure analyses, we investigated the molecular evolution of CAM as exemplified in Agave. Comparative genomics analyses among C3, C4 and CAM species revealed that core metabolic components required for CAM have ancient genomic origins traceable to non-vascular plants while regulatory proteins required for diel re-programming of metabolism have a more recent origin shared among C3, C4 and CAM species. We showed that accelerated evolution of key functional domains in proteins responsible for primary metabolism and signaling, together with a diel re-programming of the transcription of genes involved in carbon fixation, carbohydrate processing, redox homeostasis, and circadian control is required for the evolution of CAM in Agave. Furthermore, we highlighted the potential candidates contributing to the adaptation of CAM functional modules. Conclusions This work provides evidence of adaptive evolution of CAM related pathways. We showed that the core metabolic components required for CAM are shared by non-vascular plants, but regulatory proteins involved in re-reprogramming of carbon fixation and metabolite transportation appeared more recently. We propose that the accelerated evolution of key proteins together with a diel re-programming of gene expression were required for CAM evolution from C3 ancestors in Agave. Electronic supplementary material The online version of this article (10.1186/s12864-018-4964-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hengfu Yin
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Present address: Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Zhejiang, 311400, Hangzhou, China
| | - Hao-Bo Guo
- Department of Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Anne M Borland
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Priya Ranjan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Paul E Abraham
- DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Chemical Sciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA
| | - Sara S Jawdy
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - James Wachira
- Department of Biology, Morgan State University, Baltimore, MD, 21251, USA
| | - Gerald A Tuskan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Timothy J Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Stan D Wullschleger
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Hong Guo
- Department of Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Robert L Hettich
- DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Chemical Sciences Division, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA
| | - Stephen M Gross
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA.,Present address: Illumina, Inc., San Diego, CA, 92122, USA
| | - Zhong Wang
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA.,School of Natural Sciences, University of California, Merced, CA, 95343, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Axel Visel
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA.,School of Natural Sciences, University of California, Merced, CA, 95343, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Xiaohan Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. .,DOE-Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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10
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Sancar G, Brunner M. Circadian clocks and energy metabolism. Cell Mol Life Sci 2014; 71:2667-80. [PMID: 24515123 PMCID: PMC11113245 DOI: 10.1007/s00018-014-1574-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 01/08/2014] [Accepted: 01/23/2014] [Indexed: 12/25/2022]
Abstract
Circadian clocks orchestrate behavioral and physiological processes in a time-of-day dependent manner. The network of clock-controlled genes is intimately interconnected with metabolic regulatory circuits. Circadian clocks rhythmically regulate the expression and activity of key metabolic players, which in turn feed back on the circadian machinery on the transcriptional and post-transcriptional level. Mutations of clock genes are often associated with metabolic defects, especially in lipid and glucose metabolism. Accumulating data suggest that the reciprocal coordination of circadian and metabolic pathways is crucial for cellular homeostasis and the health of the organism.
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Affiliation(s)
- Gencer Sancar
- University of Heidelberg Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany,
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11
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Hotta CT, Gardner MJ, Hubbard KE, Baek SJ, Dalchau N, Suhita D, Dodd AN, Webb AAR. Modulation of environmental responses of plants by circadian clocks. PLANT, CELL & ENVIRONMENT 2007; 30:333-349. [PMID: 17263778 DOI: 10.1111/j.1365-3040.2006.01627.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Circadian clocks are signalling networks that enhance an organism's relationship with the rhythmic environment. The plant circadian clock modulates a wide range of physiological and biochemical events, such as stomatal and organ movements, photosynthesis and induction of flowering. Environmental signals regulate the phase and period of the plant circadian clock, which results in an approximate synchronization of clock outputs with external events. One of the consequences of circadian control is that stimuli of the same strength applied at different times of the day can result in responses of different intensities. This is known as 'gating'. Gating of a signal may allow plants to better process and react to the wide range and intensities of environmental signals to which they are constantly subjected. Light signalling, stomatal movements and low-temperature responses are examples of signalling pathways that are gated by the circadian clock. In this review, we describe the many levels at which the circadian clock interacts with responses to the environment. We discuss how environmental rhythms of temperature and light intensity entrain the circadian clock, how photoperiodism may be regulated by the relationship between environmental rhythms and the phasing of clock outputs, and how gating modulates the sensitivity of the clock and other responses to environmental and physiological signals. Finally, we describe evidence that the circadian clock can increase plant fitness.
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Affiliation(s)
- Carlos T Hotta
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Michael J Gardner
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Katharine E Hubbard
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Seong Jin Baek
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Neil Dalchau
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Dontamala Suhita
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Antony N Dodd
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Alex A R Webb
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
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