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Dorrell RG, Zhang Y, Liang Y, Gueguen N, Nonoyama T, Croteau D, Penot-Raquin M, Adiba S, Bailleul B, Gros V, Pierella Karlusich JJ, Zweig N, Fernie AR, Jouhet J, Maréchal E, Bowler C. Complementary environmental analysis and functional characterization of lower glycolysis-gluconeogenesis in the diatom plastid. THE PLANT CELL 2024; 36:3584-3610. [PMID: 38842420 PMCID: PMC11371179 DOI: 10.1093/plcell/koae168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/14/2024] [Accepted: 05/30/2024] [Indexed: 06/07/2024]
Abstract
Organic carbon fixed in chloroplasts through the Calvin-Benson-Bassham Cycle can be diverted toward different metabolic fates, including cytoplasmic and mitochondrial respiration, gluconeogenesis, and synthesis of diverse plastid metabolites via the pyruvate hub. In plants, pyruvate is principally produced via cytoplasmic glycolysis, although a plastid-targeted lower glycolytic pathway is known to exist in non-photosynthetic tissue. Here, we characterized a lower plastid glycolysis-gluconeogenesis pathway enabling the direct interconversion of glyceraldehyde-3-phosphate and phospho-enol-pyruvate in diatoms, ecologically important marine algae distantly related to plants. We show that two reversible enzymes required to complete diatom plastid glycolysis-gluconeogenesis, Enolase and bis-phosphoglycerate mutase (PGAM), originated through duplications of mitochondria-targeted respiratory isoforms. Through CRISPR-Cas9 mutagenesis, integrative 'omic analyses, and measured kinetics of expressed enzymes in the diatom Phaeodactylum tricornutum, we present evidence that this pathway diverts plastid glyceraldehyde-3-phosphate into the pyruvate hub, and may also function in the gluconeogenic direction. Considering experimental data, we show that this pathway has different roles dependent in particular on day length and environmental temperature, and show that the cpEnolase and cpPGAM genes are expressed at elevated levels in high-latitude oceans where diatoms are abundant. Our data provide evolutionary, meta-genomic, and functional insights into a poorly understood yet evolutionarily recurrent plastid metabolic pathway.
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Affiliation(s)
- Richard G Dorrell
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
- Laboratory of Computational and Quantitative Biology (LCQB), Institut de Biologie Paris-Seine (IBPS), CNRS, INSERM, Sorbonne Université, Paris 75005, France
| | - Youjun Zhang
- Department of Plant Metabolomics, Center of Plant Systems Biology and Biotechnology, Plovdiv 4000, Bulgaria
- Central Plant Metabolism Group, Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yue Liang
- Center of Deep Sea Research, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Nolwenn Gueguen
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, University Grenoble Alpes, CEA, INRAE, IRIG, 38000 Grenoble, France
| | - Tomomi Nonoyama
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Dany Croteau
- Institut de Biologie Physico-Chimique (IBPC), Université PSL, Paris 75005, France
| | - Mathias Penot-Raquin
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
- Laboratory of Computational and Quantitative Biology (LCQB), Institut de Biologie Paris-Seine (IBPS), CNRS, INSERM, Sorbonne Université, Paris 75005, France
| | - Sandrine Adiba
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Benjamin Bailleul
- Institut de Biologie Physico-Chimique (IBPC), Université PSL, Paris 75005, France
| | - Valérie Gros
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, University Grenoble Alpes, CEA, INRAE, IRIG, 38000 Grenoble, France
| | - Juan José Pierella Karlusich
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Nathanaël Zweig
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Alisdair R Fernie
- Department of Plant Metabolomics, Center of Plant Systems Biology and Biotechnology, Plovdiv 4000, Bulgaria
- Central Plant Metabolism Group, Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, University Grenoble Alpes, CEA, INRAE, IRIG, 38000 Grenoble, France
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, University Grenoble Alpes, CEA, INRAE, IRIG, 38000 Grenoble, France
| | - Chris Bowler
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
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2
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de Cássia Monteiro Batista R, Araújo WL, Nunes-Nesi A, Siqueira JA. Time-to-growth: photoperiod and photosynthesis make the call. TRENDS IN PLANT SCIENCE 2024:S1360-1385(24)00179-1. [PMID: 39025750 DOI: 10.1016/j.tplants.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 07/04/2024] [Accepted: 07/05/2024] [Indexed: 07/20/2024]
Abstract
The intricate regulation of flowering time in response to day length has been extensively shown. A recent study has now revealed a similar mechanism for regulating vegetative growth. Wang et al. observed that plants measure daylength as the duration of photosynthesis and metabolite production to modulate vegetative growth.
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Affiliation(s)
- Rita de Cássia Monteiro Batista
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil
| | - Wagner L Araújo
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil
| | - Adriano Nunes-Nesi
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil
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3
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Sharkey TD. The end game(s) of photosynthetic carbon metabolism. PLANT PHYSIOLOGY 2024; 195:67-78. [PMID: 38163636 PMCID: PMC11060661 DOI: 10.1093/plphys/kiad601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/27/2023] [Indexed: 01/03/2024]
Abstract
The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is remarkable how many organisms use the reaction sequence described 70 yrs ago, which is now known as the Calvin-Benson cycle or variants such as the Calvin-Benson-Bassham cycle or Benson-Calvin cycle. However, once the carbon has entered the Calvin-Benson cycle and is converted to a 3-carbon sugar, it has many potential fates. This review will examine the last stages of photosynthetic metabolism in leaves. In land plants, this process mostly involves the production of sucrose provided by an endosymbiont (the chloroplast) to its host for use and transport to the rest of the plant. Photosynthetic metabolism also usually involves the synthesis of starch, which helps maintain respiration in the dark and enables the symbiont to supply sugars during both the day and night. Other end products made in the chloroplast are closely tied to photosynthetic CO2 assimilation. These include serine from photorespiration and various amino acids, fatty acids, isoprenoids, and shikimate pathway products. I also describe 2 pathways that can short circuit parts of the Calvin-Benson cycle. These final processes of photosynthetic metabolism play many important roles in plants.
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Affiliation(s)
- Thomas D Sharkey
- MSU-DOE Plant Research Laboratory, Plant Resilience Institute, and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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4
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Song YM, Campbell S, Shiau L, Kim JK, Ott W. Noisy Delay Denoises Biochemical Oscillators. PHYSICAL REVIEW LETTERS 2024; 132:078402. [PMID: 38427894 DOI: 10.1103/physrevlett.132.078402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 11/17/2023] [Indexed: 03/03/2024]
Abstract
Genetic oscillations are generated by delayed transcriptional negative feedback loops, wherein repressor proteins inhibit their own synthesis after a temporal production delay. This delay is distributed because it arises from a sequence of noisy processes, including transcription, translocation, translation, and folding. Because the delay determines repression timing and, therefore, oscillation period, it has been commonly believed that delay noise weakens oscillatory dynamics. Here, we demonstrate that noisy delay can surprisingly denoise genetic oscillators. Specifically, moderate delay noise improves the signal-to-noise ratio and sharpens oscillation peaks, all without impacting period and amplitude. We show that this denoising phenomenon occurs in a variety of well-studied genetic oscillators, and we use queueing theory to uncover the universal mechanisms that produce it.
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Affiliation(s)
- Yun Min Song
- Department of Mathematical Sciences, KAIST, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Sean Campbell
- Department of Mathematics, University of Houston, Houston, Texas 77204, USA
| | - LieJune Shiau
- Department of Mathematics and Statistics, University of Houston Clear Lake, Houston, Texas 77058, USA
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, KAIST, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - William Ott
- Department of Mathematics, University of Houston, Houston, Texas 77204, USA
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5
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Kudo SN, Bello CCM, Artins A, Caldana C, Satake A. Assessing the impacts of genetic defects on starch metabolism in Arabidopsis plants using the carbon homeostasis model. J R Soc Interface 2023; 20:20230426. [PMID: 38016639 PMCID: PMC10684347 DOI: 10.1098/rsif.2023.0426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/30/2023] [Indexed: 11/30/2023] Open
Abstract
Starch serves as an important carbon storage mechanism for many plant species, facilitating their adaptation to the cyclic variations in the light environment, including day-night cycles as well as seasonal changes in photoperiod. By dynamically adjusting starch accumulation and degradation rates, plants maintain carbon homeostasis, enabling continuous growth under fluctuating environmental conditions. To understand dynamic nature of starch metabolism at the molecular level, it is necessary to integrate empirical knowledge from genetic defects in specific regulatory pathways into the dynamical system of starch metabolism. To achieve this, we evaluated the impact of genetic defects in the circadian clock, sugar sensing and starch degradation pathways using the carbon homeostasis model that encompasses the interplay between these pathways. Through the collection of starch metabolism data from 10 Arabidopsis mutants, we effectively fitted the experimental data to the model. The system-level assessment revealed that genetic defects in both circadian clock components and sugar sensing pathway hindered the appropriate adjustment of the starch degradation rate, particularly under long-day conditions. These findings not only confirmed the previous empirical findings but also provide the novel insights into the role of each gene within the gene regulatory network on the emergence of carbon homeostasis.
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Affiliation(s)
- Shuichi N. Kudo
- Graduate School of Systems Life Science, Kyushu University, Fukuoka 819-0395, Japan
| | | | - Anthony Artins
- Max Planck Institute of Molecular Plant Physiology, Golm/Postdam 14476, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Golm/Postdam 14476, Germany
| | - Akiko Satake
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
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6
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Siqueira JA, Zsögön A, Fernie AR, Nunes-Nesi A, Araújo WL. Does day length matter for nutrient responsiveness? TRENDS IN PLANT SCIENCE 2023; 28:1113-1123. [PMID: 37268488 DOI: 10.1016/j.tplants.2023.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/11/2023] [Accepted: 04/24/2023] [Indexed: 06/04/2023]
Abstract
For over 2500 years, considerable agronomic interest has been paid to soil fertility. Both crop domestication and the Green Revolution shifted photoperiodism and the circadian clock in cultivated species, although this contributed to an increase in the demand for chemical fertilisers. Thus, the uptake of nutrients depends on light signalling, whereas diel growth and circadian rhythms are affected by nutrient levels. Here, we argue that day length and circadian rhythms may be central regulators of the uptake and usage of nutrients, also modulating responses to toxic elements (e.g., aluminium and cadmium). Thus, we suggest that knowledge in this area might assist in developing next-generation crops with improved uptake and use efficiency of nutrients.
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Affiliation(s)
- João Antonio Siqueira
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil.
| | - Agustin Zsögön
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Adriano Nunes-Nesi
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil
| | - Wagner L Araújo
- National Institute of Science and Technology on Plant Physiology under Stress Conditions, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil.
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7
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Lee SW, Choi D, Moon H, Kim S, Kang H, Paik I, Huq E, Kim DH. PHYTOCHROME-INTERACTING FACTORS are involved in starch degradation adjustment via inhibition of the carbon metabolic regulator QUA-QUINE STARCH in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:110-123. [PMID: 36710626 DOI: 10.1111/tpj.16124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 01/19/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
As sessile organisms, plants encounter dynamic and challenging environments daily, including abiotic/biotic stresses. The regulation of carbon and nitrogen allocations for the synthesis of plant proteins, carbohydrates, and lipids is fundamental for plant growth and adaption to its surroundings. Light, one of the essential environmental signals, exerts a substantial impact on plant metabolism and resource partitioning (i.e., starch). However, it is not fully understood how light signaling affects carbohydrate production and allocation in plant growth and development. An orphan gene unique to Arabidopsis thaliana, named QUA-QUINE STARCH (QQS) is involved in the metabolic processes for partitioning of carbon and nitrogen among proteins and carbohydrates, thus influencing leaf, seed composition, and plant defense in Arabidopsis. In this study, we show that PHYTOCHROME-INTERACTING bHLH TRANSCRIPTION FACTORS (PIFs), including PIF4, are required to suppress QQS during the period at dawn, thus preventing overconsumption of starch reserves. QQS expression is significantly de-repressed in pif4 and pifQ, while repressed by overexpression of PIF4, suggesting that PIF4 and its close homologs (PIF1, PIF3, and PIF5) act as negative regulators of QQS expression. In addition, we show that the evening complex, including ELF3 is required for active expression of QQS, thus playing a positive role in starch catabolism during night-time. Furthermore, QQS is epigenetically suppressed by DNA methylation machinery, whereas histone H3 K4 methyltransferases (e.g., ATX1, ATX2, and ATXR7) and H3 acetyltransferases (e.g., HAC1 and HAC5) are involved in the expression of QQS. This study demonstrates that PIF light signaling factors help plants utilize optimal amounts of starch during the night and prevent overconsumption of starch before its biosynthesis during the upcoming day.
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Affiliation(s)
- Sang Woo Lee
- Department of Plant Science and Technology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Dasom Choi
- Department of Plant Science and Technology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Heewon Moon
- Department of Plant Science and Technology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Sujeong Kim
- Department of Plant Science and Technology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Hajeong Kang
- Department of Plant Science and Technology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Inyup Paik
- Department of Molecular Biosciences, the University of Texas at Austin, Texas, 78712, USA
| | - Enamul Huq
- Department of Molecular Biosciences, the University of Texas at Austin, Texas, 78712, USA
| | - Dong-Hwan Kim
- Department of Plant Science and Technology, Chung-Ang University, Anseong, 17546, Republic of Korea
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8
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Zepeda AC, Heuvelink E, Marcelis LFM. Non-structural carbohydrate dynamics and growth in tomato plants grown at fluctuating light and temperature. FRONTIERS IN PLANT SCIENCE 2022; 13:968881. [PMID: 36262659 PMCID: PMC9574331 DOI: 10.3389/fpls.2022.968881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/19/2022] [Indexed: 06/16/2023]
Abstract
Fluctuations in light intensity and temperature lead to periods of asynchrony between carbon (C) supply by photosynthesis and C demand by the plant organs. Storage and remobilization of non-structural carbohydrates (NSC) are important processes that allow plants to buffer these fluctuations. We aimed to test the hypothesis that C storage and remobilization can buffer the effects of temperature and light fluctuations on growth of tomato plants. Tomato plants were grown at temperature amplitudes of 3 or 10°C (deviation around the mean of 22°C) combined with integration periods (IP) of 2 or 10 days. Temperature and light were applied in Phase (high temperature simultaneously with high light intensity, (400 μmol m-2 s-1), low temperature simultaneously with low light intensity (200 μmol m-2 s-1) or in Antiphase (high temperature with low light intensity, low temperature with high light intensity). A control treatment with constant temperature (22°C) and a constant light intensity (300 μmol m-2 s-1) was also applied. After 20 days all treatments had received the same temperature and light integral. Differences in final structural dry weight were relatively small, while NSC concentrations were highly dynamic and followed changes of light and temperature (a positive correlation with decreasing temperature and increasing light intensity). High temperature and low light intensity lead to depletion of the NSC pool, but NSC level never dropped below 8% of the plant weight and this fraction was not mobilizable. Our results suggest that growing plants under fluctuating conditions do not necessarily have detrimental effects on plant growth and may improve biomass production in plants. These findings highlight the importance in the NSC pool dynamics to buffer fluctuations of light and temperature on plant structural growth.
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9
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Wang S, Steed G, Webb AAR. Circadian entrainment in Arabidopsis. PLANT PHYSIOLOGY 2022; 190:981-993. [PMID: 35512209 PMCID: PMC9516740 DOI: 10.1093/plphys/kiac204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Circadian clocks coordinate physiology and development as an adaption to the oscillating day/night cycle caused by the rotation of Earth on its axis and the changing length of day and night away from the equator caused by orbiting the sun. Circadian clocks confer advantages by entraining to rhythmic environmental cycles to ensure that internal events within the plant occur at the correct time with respect to the cyclic external environment. Advances in determining the structure of circadian oscillators and the pathways that allow them to respond to light, temperature, and metabolic signals have begun to provide a mechanistic insight to the process of entrainment in Arabidopsis (Arabidopsis thaliana). We describe the concepts of entrainment and how it occurs. It is likely that a thorough mechanistic understanding of the genetic and physiological basis of circadian entrainment will provide opportunities for crop improvement.
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Affiliation(s)
- Shouming Wang
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
- School of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China
| | - Gareth Steed
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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10
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Ishihara H, Alseekh S, Feil R, Perera P, George GM, Niedźwiecki P, Arrivault S, Zeeman SC, Fernie AR, Lunn JE, Smith AM, Stitt M. Rising rates of starch degradation during daytime and trehalose 6-phosphate optimize carbon availability. PLANT PHYSIOLOGY 2022; 189:1976-2000. [PMID: 35486376 PMCID: PMC9342969 DOI: 10.1093/plphys/kiac162] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/11/2022] [Indexed: 05/06/2023]
Abstract
Many plants, including Arabidopsis (Arabidopsis thaliana), accumulate starch in the light and remobilize it to support maintenance and growth at night. Starch synthesis and degradation are usually viewed as temporally separate processes. Recently, we reported that starch is also degraded in the light. Degradation rates are generally low early in the day but rise with time. Here, we show that the rate of degradation in the light depends on time relative to dawn rather than dusk. We also show that degradation in the light is inhibited by trehalose 6-phosphate, a signal for sucrose availability. The observed responses of degradation in the light can be simulated by a skeletal model in which the rate of degradation is a function of starch content divided by time remaining until dawn. The fit is improved by extension to include feedback inhibition of starch degradation by trehalose 6-phosphate. We also investigate possible functions of simultaneous starch synthesis and degradation in the light, using empirically parameterized models and experimental approaches. The idea that this cycle buffers growth against falling rates of photosynthesis at twilight is supported by data showing that rates of protein and cell wall synthesis remain high during a simulated dusk twilight. Degradation of starch in the light may also counter over-accumulation of starch in long photoperiods and stabilize signaling around dusk. We conclude that starch degradation in the light is regulated by mechanisms similar to those that operate at night and is important for stabilizing carbon availability and signaling, thus optimizing growth in natural light conditions.
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Affiliation(s)
- Hirofumi Ishihara
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Saleh Alseekh
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
- Center for Plant Systems Biology and Biotechnology, Plovdiv 4000, Bulgaria
| | - Regina Feil
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Pumi Perera
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Gavin M George
- Institute of Molecular Plant Biology, ETH Zürich, Zürich, Switzerland
| | - Piotr Niedźwiecki
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Stephanie Arrivault
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zürich, Zürich, Switzerland
| | - Alisdair R Fernie
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
- Center for Plant Systems Biology and Biotechnology, Plovdiv 4000, Bulgaria
| | - John E Lunn
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Alison M Smith
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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11
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Courbier S. Breaking Dawn: The twilight of starch degradation in the light. PLANT PHYSIOLOGY 2022; 189:1887-1889. [PMID: 35522005 PMCID: PMC9342960 DOI: 10.1093/plphys/kiac202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 04/17/2022] [Indexed: 06/14/2023]
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12
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Alexandre Moraes T, Mengin V, Peixoto B, Encke B, Krohn N, Höhne M, Krause U, Stitt M. The circadian clock mutant lhy cca1 elf3 paces starch mobilization to dawn despite severely disrupted circadian clock function. PLANT PHYSIOLOGY 2022; 189:2332-2356. [PMID: 35567528 PMCID: PMC9348821 DOI: 10.1093/plphys/kiac226] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Many plants, including Arabidopsis (Arabidopsis thaliana), accumulate starch in the daytime and remobilize it to support maintenance and growth at night. Starch accumulation is increased when carbon is in short supply, for example, in short photoperiods. Mobilization is paced to exhaust starch around dawn, as anticipated by the circadian clock. This diel pattern of turnover is largely robust against loss of day, dawn, dusk, or evening clock components. Here, we investigated diel starch turnover in the triple circadian clock mutant lhy cca1 elf3, which lacks the LATE ELONGATED HYPOCOTYL and the CIRCADIAN CLOCK-ASSOCIATED1 (CCA1) dawn components and the EARLY FLOWERING3 (ELF3) evening components of the circadian clock. The diel oscillations of transcripts for the remaining clock components and related genes like REVEILLE and PHYTOCHROME-INTERACING FACTOR family members exhibited attenuated amplitudes and altered peak time, weakened dawn dominance, and decreased robustness against changes in the external light-dark cycle. The triple mutant was unable to increase starch accumulation in short photoperiods. However, it was still able to pace starch mobilization to around dawn in different photoperiods and growth irradiances and to around 24 h after the previous dawn in T17 and T28 cycles. The triple mutant was able to slow down starch mobilization after a sudden low-light day or a sudden early dusk, although in the latter case it did not fully compensate for the lengthened night. Overall, there was a slight trend to less linear mobilization of starch. Thus, starch mobilization can be paced rather robustly to dawn despite a major disruption of the transcriptional clock. It is proposed that temporal information can be delivered from clock components or a semi-autonomous oscillator.
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Affiliation(s)
| | - Virginie Mengin
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Bruno Peixoto
- Instituto Gulbenkian de Ciência, Oeiras 2780-156,Portugal
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Oeiras 2780-157,Portugal
| | - Beatrice Encke
- Systematic Botany and Biodiversity, Humboldt University of Berlin, Berlin D-10115, Germany
| | - Nicole Krohn
- Abteilung für Parodontologie und Synoptische Zahnmedizin, Charité Universitätsmedizin, Berlin 14197, Germany
| | - Melanie Höhne
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| | - Ursula Krause
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
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13
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Li J, Kim YJ, Zhang D. Source-To-Sink Transport of Sugar and Its Role in Male Reproductive Development. Genes (Basel) 2022; 13:1323. [PMID: 35893060 PMCID: PMC9329892 DOI: 10.3390/genes13081323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/30/2022] [Accepted: 07/07/2022] [Indexed: 02/01/2023] Open
Abstract
Sucrose is produced in leaf mesophyll cells via photosynthesis and exported to non-photosynthetic sink tissues through the phloem. The molecular basis of source-to-sink long-distance transport in cereal crop plants is of importance due to its direct influence on grain yield-pollen grains, essential for male fertility, are filled with sugary starch, and rely on long-distance sugar transport from source leaves. Here, we overview sugar partitioning via phloem transport in rice, especially where relevant for male reproductive development. Phloem loading and unloading in source leaves and sink tissues uses a combination of the symplastic, apoplastic, and/or polymer trapping pathways. The symplastic and polymer trapping pathways are passive processes, correlated with source activity and sugar gradients. In contrast, apoplastic phloem loading/unloading involves active processes and several proteins, including SUcrose Transporters (SUTs), Sugars Will Eventually be Exported Transporters (SWEETs), Invertases (INVs), and MonoSaccharide Transporters (MSTs). Numerous transcription factors combine to create a complex network, such as DNA binding with One Finger 11 (DOF11), Carbon Starved Anther (CSA), and CSA2, which regulates sugar metabolism in normal male reproductive development and in response to changes in environmental signals, such as photoperiod.
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Affiliation(s)
- Jingbin Li
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Yu-Jin Kim
- Department of Life Science and Environmental Biochemistry, Pusan National University, Miryang 50463, Korea;
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China;
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA 5064, Australia
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14
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Feike D, Pike M, Gurrieri L, Graf A, Smith AM. A dominant mutation in β-AMYLASE1 disrupts nighttime control of starch degradation in Arabidopsis leaves. PLANT PHYSIOLOGY 2022; 188:1979-1992. [PMID: 34958379 PMCID: PMC8968401 DOI: 10.1093/plphys/kiab603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) leaves possess a mechanism that couples the rate of nighttime starch degradation to the anticipated time of dawn, thus preventing premature exhaustion of starch and nighttime starvation. To shed light on the mechanism, we screened a mutagenized population of a starvation reporter line and isolated a mutant that starved prior to dawn. The mutant had accelerated starch degradation, and the rate was not adjusted to time of dawn. The mutation responsible led to a single amino acid change (S132N) in the starch degradation enzyme BETA-AMYLASE1 (BAM1; mutant allele named bam1-2D), resulting in a dominant, gain-of-function phenotype. Complete loss of BAM1 (in bam1-1) did not affect rates of starch degradation, while expression of BAM1(S132N) in bam1-1 recapitulated the accelerated starch degradation phenotype of bam1-2D. In vitro analysis of recombinant BAM1 and BAM1(S132N) proteins revealed no differences in kinetic or stability properties, but in leaf extracts, BAM1(S132N) apparently had a higher affinity than BAM1 for an established binding partner required for normal rates of starch degradation, LIKE SEX FOUR1 (LSF1). Genetic approaches showed that BAM1(S132N) itself is likely responsible for accelerated starch degradation in bam1-2D and that this activity requires LSF1. Analysis of plants expressing BAM1 with alanine or aspartate rather than serine at position 132 indicated that the gain-of-function phenotype is not related to phosphorylation status at this position. Our results strengthen the view that control of starch degradation in wild-type plants involves dynamic physical interactions of degradative enzymes and related proteins with a central role for complexes containing LSF1.
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Affiliation(s)
| | | | - Libero Gurrieri
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | - Alexander Graf
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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15
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Eve A. Transitions in development - an interview with Antonio Scialdone. Development 2022; 149:dev200704. [PMID: 35315485 DOI: 10.1242/dev.200704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Antonio Scialdone is a Junior Group Leader at the Helmholtz Zentrum München, Institute of Epigenetics and Stem Cells, in Germany. Trained as a theoretical physicist, Antonio now uses multidisciplinary approaches, combining both computational methods and physical models, to study cellular decision making. We met Antonio over Teams to learn more about his experiences moving between different research fields and the transition to becoming a group leader.
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16
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David LC, Lee SK, Bruderer E, Abt MR, Fischer-Stettler M, Tschopp MA, Solhaug EM, Sanchez K, Zeeman SC. BETA-AMYLASE9 is a plastidial nonenzymatic regulator of leaf starch degradation. PLANT PHYSIOLOGY 2022; 188:191-207. [PMID: 34662400 PMCID: PMC8774843 DOI: 10.1093/plphys/kiab468] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/28/2021] [Indexed: 06/13/2023]
Abstract
β-Amylases (BAMs) are key enzymes of transitory starch degradation in chloroplasts, a process that buffers the availability of photosynthetically fixed carbon over the diel cycle to maintain energy levels and plant growth at night. However, during vascular plant evolution, the BAM gene family diversified, giving rise to isoforms with different compartmentation and biological activities. Here, we characterized BETA-AMYLASE 9 (BAM9) of Arabidopsis (Arabidopsis thaliana). Among the BAMs, BAM9 is most closely related to BAM4 but is more widely conserved in plants. BAM9 and BAM4 share features including their plastidial localization and lack of measurable α-1,4-glucan hydrolyzing capacity. BAM4 is a regulator of starch degradation, and bam4 mutants display a starch-excess phenotype. Although bam9 single mutants resemble the wild-type (WT), genetic experiments reveal that the loss of BAM9 markedly enhances the starch-excess phenotypes of mutants already impaired in starch degradation. Thus, BAM9 also regulates starch breakdown, but in a different way. Interestingly, BAM9 gene expression is responsive to several environmental changes, while that of BAM4 is not. Furthermore, overexpression of BAM9 in the WT reduced leaf starch content, but overexpression in bam4 failed to complement fully that mutant's starch-excess phenotype, suggesting that BAM9 and BAM4 are not redundant. We propose that BAM9 activates starch degradation, helping to manage carbohydrate availability in response to fluctuations in environmental conditions. As such, BAM9 represents an interesting gene target to explore in crop species.
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Affiliation(s)
- Laure C David
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Sang-Kyu Lee
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Eduard Bruderer
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Melanie R Abt
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Michaela Fischer-Stettler
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Marie-Aude Tschopp
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Erik M Solhaug
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Katarzyna Sanchez
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich CH-8092, Switzerland
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17
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Li R, Zheng W, Jiang M, Zhang H. A review of starch biosynthesis in cereal crops and its potential breeding applications in rice ( Oryza Sativa L.). PeerJ 2022; 9:e12678. [PMID: 35036154 PMCID: PMC8710062 DOI: 10.7717/peerj.12678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/02/2021] [Indexed: 11/20/2022] Open
Abstract
Starch provides primary storage of carbohydrates, accounting for approximately 85% of the dry weight of cereal endosperm. Cereal seeds contribute to maximum annual starch production and provide the primary food for humans and livestock worldwide. However, the growing demand for starch in food and industry and the increasing loss of arable land with urbanization emphasizes the urgency to understand starch biosynthesis and its regulation. Here, we first summarized the regulatory signaling pathways about leaf starch biosynthesis. Subsequently, we paid more attention to how transcriptional factors (TFs) systematically respond to various stimulants via the regulation of the enzymes during starch biosynthesis. Finally, some strategies to improve cereal yield and quality were put forward based on the previous reports. This review would collectively help to design future studies on starch biosynthesis in cereal crops.
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Affiliation(s)
- Ruiqing Li
- State Key Laboratory of Rice Biology and Chinese National Center for Rice Improvement, China National Rice Research Institute, Hangzhou, China.,College of Agronomy, Anhui Agricultural University, Hefei, China
| | - Wenyin Zheng
- College of Agronomy, Anhui Agricultural University, Hefei, China
| | - Meng Jiang
- State Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou, China
| | - Huali Zhang
- State Key Laboratory of Rice Biology and Chinese National Center for Rice Improvement, China National Rice Research Institute, Hangzhou, China
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18
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Chu KL, Koley S, Jenkins LM, Bailey SR, Kambhampati S, Foley K, Arp JJ, Morley SA, Czymmek KJ, Bates PD, Allen DK. Metabolic flux analysis of the non-transitory starch tradeoff for lipid production in mature tobacco leaves. Metab Eng 2022; 69:231-248. [PMID: 34920088 PMCID: PMC8761171 DOI: 10.1016/j.ymben.2021.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 10/12/2021] [Accepted: 12/11/2021] [Indexed: 12/19/2022]
Abstract
The metabolic plasticity of tobacco leaves has been demonstrated via the generation of transgenic plants that can accumulate over 30% dry weight as triacylglycerols. In investigating the changes in carbon partitioning in these high lipid-producing (HLP) leaves, foliar lipids accumulated stepwise over development. Interestingly, non-transient starch was observed to accumulate with plant age in WT but not HLP leaves, with a drop in foliar starch concurrent with an increase in lipid content. The metabolic carbon tradeoff between starch and lipid was studied using 13CO2-labeling experiments and isotopically nonstationary metabolic flux analysis, not previously applied to the mature leaves of a crop. Fatty acid synthesis was investigated through assessment of acyl-acyl carrier proteins using a recently derived quantification method that was extended to accommodate isotopic labeling. Analysis of labeling patterns and flux modeling indicated the continued production of unlabeled starch, sucrose cycling, and a significant contribution of NADP-malic enzyme to plastidic pyruvate production for the production of lipids in HLP leaves, with the latter verified by enzyme activity assays. The results suggest an inherent capacity for a developmentally regulated carbon sink in tobacco leaves and may in part explain the uniquely successful leaf lipid engineering efforts in this crop.
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Affiliation(s)
- Kevin L Chu
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Somnath Koley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Lauren M Jenkins
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Sally R Bailey
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | | | - Kevin Foley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Jennifer J Arp
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Stewart A Morley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Kirk J Czymmek
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Philip D Bates
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-6340, USA
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA.
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19
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Dewar R, Hölttä T, Salmon Y. Exploring optimal stomatal control under alternative hypotheses for the regulation of plant sources and sinks. THE NEW PHYTOLOGIST 2022; 233:639-654. [PMID: 34637543 DOI: 10.1111/nph.17795] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
Experimental evidence that nonstomatal limitations to photosynthesis (NSLs) correlate with leaf sugar and/or leaf water status suggests the possibility that stomata adjust to maximise photosynthesis through a trade-off between leaf CO2 supply and NSLs, potentially involving source-sink interactions. However, the mechanisms regulating NSLs and sink strength, as well as their implications for stomatal control, remain uncertain. We used an analytically solvable model to explore optimal stomatal control under alternative hypotheses for source and sink regulation. We assumed that either leaf sugar concentration or leaf water potential regulates NSLs, and that either phloem turgor pressure or phloem sugar concentration regulates sink phloem unloading. All hypotheses led to realistic stomatal responses to light, CO2 and air humidity, including conservative behaviour for the intercellular-to-atmospheric CO2 concentration ratio. Sugar-regulated and water-regulated NSLs are distinguished by the presence/absence of a stomatal closure response to changing sink strength. Turgor-regulated and sugar-regulated phloem unloading are distinguished by the presence/absence of stomatal closure under drought and avoidance/occurrence of negative phloem turgor. Results from girdling and drought experiments on Pinus sylvestris, Betula pendula, Populus tremula and Picea abies saplings are consistent with optimal stomatal control under sugar-regulated NSLs and turgor-regulated unloading. Our analytical results provide a simple representation of stomatal responses to above-ground and below-ground environmental factors and sink activity.
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Affiliation(s)
- Roderick Dewar
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
| | - Yann Salmon
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
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20
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Ruocco M, Barrote I, Hofman JD, Pes K, Costa MM, Procaccini G, Silva J, Dattolo E. Daily Regulation of Key Metabolic Pathways in Two Seagrasses Under Natural Light Conditions. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.757187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The circadian clock is an endogenous time-keeping mechanism that enables organisms to adapt to external environmental cycles. It produces rhythms of plant metabolism and physiology, and interacts with signaling pathways controlling daily and seasonal environmental responses through gene expression regulation. Downstream metabolic outputs, such as photosynthesis and sugar metabolism, besides being affected by the clock, can also contribute to the circadian timing itself. In marine plants, studies of circadian rhythms are still way behind in respect to terrestrial species, which strongly limits the understanding of how they coordinate their physiology and energetic metabolism with environmental signals at sea. Here, we provided a first description of daily timing of key core clock components and clock output pathways in two seagrass species, Cymodocea nodosa and Zostera marina (order Alismatales), co-occurring at the same geographic location, thus exposed to identical natural variations in photoperiod. Large differences were observed between species in the daily timing of accumulation of transcripts related to key metabolic pathways, such as photosynthesis and sucrose synthesis/transport, highlighting the importance of intrinsic biological, and likely ecological attributes of the species in determining the periodicity of functions. The two species exhibited a differential sensitivity to light-to-dark and dark-to-light transition times and could adopt different growth timing based on a differential strategy of resource allocation and mobilization throughout the day, possibly coordinated by the circadian clock. This behavior could potentially derive from divergent evolutionary adaptations of the species to their bio-geographical range of distributions.
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21
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Peixoto B, Moraes TA, Mengin V, Margalha L, Vicente R, Feil R, Höhne M, Sousa AGG, Lilue J, Stitt M, Lunn JE, Baena-González E. Impact of the SnRK1 protein kinase on sucrose homeostasis and the transcriptome during the diel cycle. PLANT PHYSIOLOGY 2021; 187:1357-1373. [PMID: 34618060 PMCID: PMC8566312 DOI: 10.1093/plphys/kiab350] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/09/2021] [Indexed: 05/04/2023]
Abstract
SNF1-related Kinase 1 (SnRK1) is an evolutionarily conserved protein kinase with key functions in energy management during stress responses in plants. To address a potential role of SnRK1 under favorable conditions, we performed a metabolomic and transcriptomic characterization of rosettes of 20-d-old Arabidopsis (Arabidopsis thaliana) plants of SnRK1 gain- and loss-of-function mutants during the regular diel cycle. Our results show that SnRK1 manipulation alters the sucrose and trehalose 6-phosphate (Tre6P) relationship, influencing how the sucrose content is translated into Tre6P accumulation and modulating the flux of carbon to the tricarboxylic acid cycle downstream of Tre6P signaling. On the other hand, daily cycles of Tre6P accumulation were accompanied by changes in SnRK1 signaling, leading to a maximum in the expression of SnRK1-induced genes at the end of the night, when Tre6P levels are lowest, and to a minimum at the end of the day, when Tre6P levels peak. The expression of SnRK1-induced genes was strongly reduced by transient Tre6P accumulation in an inducible Tre6P synthase (otsA) line, further suggesting the involvement of Tre6P in the diel oscillations in SnRK1 signaling. Transcriptional profiling of wild-type plants and SnRK1 mutants also uncovered defects that are suggestive of an iron sufficiency response and of a matching induction of sulfur acquisition and assimilation when SnRK1 is depleted. In conclusion, under favorable growth conditions, SnRK1 plays a role in sucrose homeostasis and transcriptome remodeling in autotrophic tissues and its activity is influenced by diel fluctuations in Tre6P levels.
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Affiliation(s)
- Bruno Peixoto
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
| | - Thiago A Moraes
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Present address: Crop Science Centre, Lawrence Weaver Road, Cambridge CB3 0LE, UK
| | - Virginie Mengin
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Present address: University of Essex, School of Life Sciences, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Leonor Margalha
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
| | - Rubén Vicente
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
| | - Regina Feil
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Melanie Höhne
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - António G G Sousa
- Instituto Gulbenkian de Ciência, Bioinformatics Unit, 2780-156 Oeiras, Portugal
| | - Jingtao Lilue
- Instituto Gulbenkian de Ciência, Bioinformatics Unit, 2780-156 Oeiras, Portugal
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Elena Baena-González
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal and GREEN-IT Bioresources for Sustainability, ITQB NOVA, 2780-157 Oeiras, Portugal
- Author for communication:
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22
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Miguel-Tomé S, Llinás RR. Broadening the definition of a nervous system to better understand the evolution of plants and animals. PLANT SIGNALING & BEHAVIOR 2021; 16:1927562. [PMID: 34120565 PMCID: PMC8331040 DOI: 10.1080/15592324.2021.1927562] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 05/10/2023]
Abstract
Most textbook definitions recognize only animals as having nervous systems. However, for the past couple decades, botanists have been meticulously studying long-distance signaling systems in plants, and some researchers have stated that plants have a simple nervous system. Thus, an academic conflict has emerged between those who defend and those who deny the existence of a nervous system in plants. This article analyses that debate, and we propose an alternative to answering yes or no: broadening the definition of a nervous system to include plants. We claim that a definition broader than the current one, which is based only on a phylogenetic viewpoint, would be helpful in obtaining a deeper understanding of how evolution has driven the features of signal generation, transmission and processing in multicellular beings. Also, we propose two possible definitions and exemplify how broader a definition allows for new viewpoints on the evolution of plants, animals and the nervous system.
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Affiliation(s)
- Sergio Miguel-Tomé
- Grupo De Investigación En Minería De Datos (Mida), Universidad De Salamanca, Salamanca, Spain
| | - Rodolfo R. Llinás
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA
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23
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Viana AJC, Matiolli CC, Newman DW, Vieira JGP, Duarte GT, Martins MCM, Gilbault E, Hotta CT, Caldana C, Vincentz M. The sugar-responsive circadian clock regulator bZIP63 modulates plant growth. THE NEW PHYTOLOGIST 2021; 231:1875-1889. [PMID: 34053087 PMCID: PMC9292441 DOI: 10.1111/nph.17518] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 05/18/2021] [Indexed: 05/02/2023]
Abstract
Adjustment to energy starvation is crucial to ensure growth and survival. In Arabidopsis thaliana (Arabidopsis), this process relies in part on the phosphorylation of the circadian clock regulator bZIP63 by SUCROSE non-fermenting RELATED KINASE1 (SnRK1), a key mediator of responses to low energy. We investigated the effects of mutations in bZIP63 on plant carbon (C) metabolism and growth. Results from phenotypic, transcriptomic and metabolomic analysis of bZIP63 mutants prompted us to investigate the starch accumulation pattern and the expression of genes involved in starch degradation and in the circadian oscillator. bZIP63 mutation impairs growth under light-dark cycles, but not under constant light. The reduced growth likely results from the accentuated C depletion towards the end of the night, which is caused by the accelerated starch degradation of bZIP63 mutants. The diel expression pattern of bZIP63 is dictated by both the circadian clock and energy levels, which could determine the changes in the circadian expression of clock and starch metabolic genes observed in bZIP63 mutants. We conclude that bZIP63 composes a regulatory interface between the metabolic and circadian control of starch breakdown to optimize C usage and plant growth.
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Affiliation(s)
- Américo J. C. Viana
- Centro de Biologia Molecular e Engenharia GenéticaDepartamento de Biologia VegetalInstituto de BiologiaUniversidade Estadual de CampinasCEP 13083‐875, CP 6010CampinasSPBrazil
| | - Cleverson C. Matiolli
- Centro de Biologia Molecular e Engenharia GenéticaDepartamento de Biologia VegetalInstituto de BiologiaUniversidade Estadual de CampinasCEP 13083‐875, CP 6010CampinasSPBrazil
| | - David W. Newman
- Centro de Biologia Molecular e Engenharia GenéticaDepartamento de Biologia VegetalInstituto de BiologiaUniversidade Estadual de CampinasCEP 13083‐875, CP 6010CampinasSPBrazil
| | - João G. P. Vieira
- Centro de Biologia Molecular e Engenharia GenéticaDepartamento de Biologia VegetalInstituto de BiologiaUniversidade Estadual de CampinasCEP 13083‐875, CP 6010CampinasSPBrazil
| | - Gustavo T. Duarte
- Centro de Biologia Molecular e Engenharia GenéticaDepartamento de Biologia VegetalInstituto de BiologiaUniversidade Estadual de CampinasCEP 13083‐875, CP 6010CampinasSPBrazil
| | - Marina C. M. Martins
- Brazilian Bioethanol Science and Technology Laboratory (CTBE/CNPEM)Rua Giuseppe Máximo Scolfaro 10000CampinasSPCEP 13083‐970Brazil
- Max‐Planck Partner GroupBrazilian Bioethanol Science and Technology Laboratory (CTBE/CNPEM)Campinas, SPBrazil
- Laboratory of Plant Physiological EcologyDepartment of BotanyInstitute of BiosciencesUniversity of São PauloSão Paulo, SPCEP 05508‐090Brazil
| | - Elodie Gilbault
- Institut Jean‐Pierre BourginINRAEAgroParisTechUniversité Paris‐SaclayVersailles78000France
| | - Carlos T. Hotta
- Departamento de BioquímicaInstituto de QuímicaUniversidade de São PauloSão Paulo, SPCEP 05508‐000Brazil
| | - Camila Caldana
- Brazilian Bioethanol Science and Technology Laboratory (CTBE/CNPEM)Rua Giuseppe Máximo Scolfaro 10000CampinasSPCEP 13083‐970Brazil
- Max‐Planck Partner GroupBrazilian Bioethanol Science and Technology Laboratory (CTBE/CNPEM)Campinas, SPBrazil
- Max Planck Institute of Molecular Plant PhysiologyAm Mühlenberg 114476 PotsdamGolmGermany
| | - Michel Vincentz
- Centro de Biologia Molecular e Engenharia GenéticaDepartamento de Biologia VegetalInstituto de BiologiaUniversidade Estadual de CampinasCEP 13083‐875, CP 6010CampinasSPBrazil
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Mérida A, Fettke J. Starch granule initiation in Arabidopsis thaliana chloroplasts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:688-697. [PMID: 34051021 DOI: 10.1111/tpj.15359] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/14/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
The initiation of starch granule formation and the mechanism controlling the number of granules per plastid have been some of the most elusive aspects of starch metabolism. This review covers the advances made in the study of these processes. The analyses presented herein depict a scenario in which starch synthase isoform 4 (SS4) provides the elongating activity necessary for the initiation of starch granule formation. However, this protein does not act alone; other polypeptides are required for the initiation of an appropriate number of starch granules per chloroplast. The functions of this group of polypeptides include providing suitable substrates (maltooligosaccharides) to SS4, the localization of the starch initiation machinery to the thylakoid membranes, and facilitating the correct folding of SS4. The number of starch granules per chloroplast is tightly regulated and depends on the developmental stage of the leaves and their metabolic status. Plastidial phosphorylase (PHS1) and other enzymes play an essential role in this process since they are necessary for the synthesis of the substrates used by the initiation machinery. The mechanism of starch granule formation initiation in Arabidopsis seems to be generalizable to other plants and also to the synthesis of long-term storage starch. The latter, however, shows specific features due to the presence of more isoforms, the absence of constantly recurring starch synthesis and degradation, and the metabolic characteristics of the storage sink organs.
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Affiliation(s)
- Angel Mérida
- Institute of Plant Biochemistry and Photosynthesis (IBVF), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Sevilla (US), Avda Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Joerg Fettke
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, 14476, Germany
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25
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Gerlin L, Escourrou A, Cassan C, Maviane Macia F, Peeters N, Genin S, Baroukh C. Unravelling physiological signatures of tomato bacterial wilt and xylem metabolites exploited by Ralstonia solanacearum. Environ Microbiol 2021; 23:5962-5978. [PMID: 33876545 DOI: 10.1111/1462-2920.15535] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 02/06/2023]
Abstract
The plant pathogen Ralstonia solanacearum uses plant resources to intensely proliferate in xylem vessels and provoke plant wilting. We combined automatic phenotyping and tissue/xylem quantitative metabolomics of infected tomato plants to decipher the dynamics of bacterial wilt. Daily acquisition of physiological parameters such as transpiration and growth were performed. Measurements allowed us to identify a tipping point in bacterial wilt dynamics. At this tipping point, the reached bacterial density brutally disrupts plant physiology and rapidly induces its death. We compared the metabolic and physiological signatures of the infection with drought stress, and found that similar changes occur. Quantitative dynamics of xylem content enabled us to identify glutamine (and asparagine) as primary resources R. solanacearum consumed during its colonization phase. An abundant production of putrescine was also observed during the infection process and was strongly correlated with in planta bacterial growth. Dynamic profiling of xylem metabolites confirmed that glutamine is the favoured substrate of R. solanacearum. On the other hand, a triple mutant strain unable to metabolize glucose, sucrose and fructose appears to be only weakly reduced for in planta growth and pathogenicity.
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Affiliation(s)
- Léo Gerlin
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Antoine Escourrou
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Cédric Cassan
- UMR BFP, Université de Bordeaux, INRAE, 33882 Villenave d'Ornon, France.,Bordeaux Metabolome, MetaboHUB, PHENOME-EMPHASIS, 33140 Villenave d'Ornon, France
| | - Felicià Maviane Macia
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France.,Toulouse-Plant-Microbe-Phenotyping (TPMP), PHENOTOUL PHENOME-EMPHASIS LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Nemo Peeters
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France.,Toulouse-Plant-Microbe-Phenotyping (TPMP), PHENOTOUL PHENOME-EMPHASIS LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Stéphane Genin
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Caroline Baroukh
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
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26
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Prasetyaningrum P, Mariotti L, Valeri MC, Novi G, Dhondt S, Inzé D, Perata P, van Veen H. Nocturnal gibberellin biosynthesis is carbon dependent and adjusts leaf expansion rates to variable conditions. PLANT PHYSIOLOGY 2021; 185:228-239. [PMID: 33631808 PMCID: PMC8133661 DOI: 10.1093/plphys/kiaa019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/27/2020] [Indexed: 05/02/2023]
Abstract
Optimal plant growth performance requires that the presence and action of growth signals, such as gibberellins (GAs), are coordinated with the availability of photo-assimilates. Here, we studied the links between GA biosynthesis and carbon availability, and the subsequent effects on growth. We established that carbon availability, light and dark cues, and the circadian clock ensure the timing and magnitude of GA biosynthesis and that disruption of these factors results in reduced GA levels and expression of downstream genes. Carbon-dependent nighttime induction of gibberellin 3-beta-dioxygenase 1 (GA3ox1) was severely hampered when preceded by reduced daytime light availability, leading specifically to reduced bioactive GA4 levels, and coinciding with a decline in leaf expansion rate during the night. We attributed this decline in leaf expansion mostly to reduced photo-assimilates. However, plants in which GA limitation was alleviated had significantly improved leaf expansion, demonstrating the relevance of GAs in growth control under varying carbon availability. Carbon-dependent expression of upstream GA biosynthesis genes (Kaurene synthase and gibberellin 20 oxidase 1, GA20ox1) was not translated into metabolite changes within this short timeframe. We propose a model in which the extent of nighttime biosynthesis of bioactive GA4 by GA3ox1 is determined by nighttime consumption of starch reserves, thus providing day-to-day adjustments of GA responses.
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Affiliation(s)
| | - Lorenzo Mariotti
- Department of Agriculture, Food and Environment, University of Pisa, Pisa 56124, Italy
| | | | - Giacomo Novi
- PLANTLAB, Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa 56127, Italy
| | - Stijn Dhondt
- Center for Plant Systems Biology, Ghent University, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Dirk Inzé
- Center for Plant Systems Biology, Ghent University, VIB, 9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Pierdomenico Perata
- PLANTLAB, Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa 56127, Italy
| | - Hans van Veen
- PLANTLAB, Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa 56127, Italy
- Department of Plantecophysiology, Institute of Environmental Biology, Utrecht University, 3584 CH Utrecht, Netherlands
- Author for communication:
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27
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van Hoogdalem M, Shapulatov U, Sergeeva L, Busscher-Lange J, Schreuder M, Jamar D, van der Krol AR. A temperature regime that disrupts clock-controlled starch mobilization induces transient carbohydrate starvation, resulting in compact growth. JOURNAL OF EXPERIMENTAL BOTANY 2021:erab075. [PMID: 33617638 DOI: 10.1093/jxb/erab075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Indexed: 06/12/2023]
Abstract
In nature plants are usually subjected to a light/temperature regime of warm day and cold night (referred to as +DIF). Compared to growth under +DIF, Arabidopsis plants show compact growth under the same photoperiod, but with an inverse temperature regime (cold day and warm night: -DIF). Here we show that -DIF differentially affects the phase and amplitude of core clock gene expression. Under -DIF the phase of the morning clock gene CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) is delayed, similar to that of plants grown on low sucrose. Indeed, under -DIF carbohydrate (CHO) starvation marker genes are specifically upregulated at the End of the Night (EN) in Arabidopsis rosettes. However, only in inner-rosette tissue (small sink leaves and petioles of older leaves) sucrose levels are lower under -DIF compared to under +DIF, suggesting that sucrose in source leaf blades is not sensed for CHO status and that sucrose transport from source to sink may be impaired at EN. CHO-starvation under -DIF correlated with increased starch breakdown during the night and decreased starch accumulation during the day. Moreover, we demonstrate that different ways of inducing CHO-starvation all link to reduced growth of sink leaves. Practical implications for control of plant growth in horticulture are discussed.
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Affiliation(s)
- Mark van Hoogdalem
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
- Current Business Unit Greenhouse Horticulture, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Umidjon Shapulatov
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
- Current Department of Botany and Plant Physiology, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Lidiya Sergeeva
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Jacqueline Busscher-Lange
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
- Business Unit Bioscience, Wageningen Plant Research, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Mariëlle Schreuder
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Diaan Jamar
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Alexander R van der Krol
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg, Wageningen, The Netherlands
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28
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Preiser AL, Banerjee A, Weise SE, Renna L, Brandizzi F, Sharkey TD. Phosphoglucoisomerase Is an Important Regulatory Enzyme in Partitioning Carbon out of the Calvin-Benson Cycle. FRONTIERS IN PLANT SCIENCE 2020; 11:580726. [PMID: 33362810 PMCID: PMC7758399 DOI: 10.3389/fpls.2020.580726] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/18/2020] [Indexed: 05/04/2023]
Abstract
Phosphoglucoisomerase (PGI) isomerizes fructose 6-phosphate (F6P) and glucose 6-phosphate (G6P) in starch and sucrose biosynthesis. Both plastidic and cytosolic isoforms are found in plant leaves. Using recombinant enzymes and isolated chloroplasts, we have characterized the plastidic and cytosolic isoforms of PGI. We have found that the Arabidopsis plastidic PGI K m for G6P is three-fold greater compared to that for F6P and that erythrose 4-phosphate is a key regulator of PGI activity. Additionally, the K m of spinach plastidic PGI can be dynamically regulated in the dark compared to the light and increases by 200% in the dark. We also found that targeting Arabidopsis cytosolic PGI into plastids of Nicotiana tabacum disrupts starch accumulation and degradation. Our results, in combination with the observation that plastidic PGI is not in equilibrium, indicates that PGI is an important regulatory enzyme that restricts flow and acts as a one-way valve preventing backflow of G6P into the Calvin-Benson cycle. We propose the PGI may be manipulated to improve flow of carbon to desired targets of biotechnology.
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Affiliation(s)
- Alyssa L. Preiser
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Aparajita Banerjee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Sean E. Weise
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Luciana Renna
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Federica Brandizzi
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Plant Biology, Michigan State University, East Lansing, MI, United States
| | - Thomas D. Sharkey
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
- Plant Resilience Institute, Michigan State University, East Lansing, MI, United States
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29
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Urquidi-Camacho RA, Lokdarshi A, von Arnim AG. Translational gene regulation in plants: A green new deal. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1597. [PMID: 32367681 PMCID: PMC9258721 DOI: 10.1002/wrna.1597] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 01/09/2023]
Abstract
The molecular machinery for protein synthesis is profoundly similar between plants and other eukaryotes. Mechanisms of translational gene regulation are embedded into the broader network of RNA-level processes including RNA quality control and RNA turnover. However, over eons of their separate history, plants acquired new components, dropped others, and generally evolved an alternate way of making the parts list of protein synthesis work. Research over the past 5 years has unveiled how plants utilize translational control to defend themselves against viruses, regulate translation in response to metabolites, and reversibly adjust translation to a wide variety of environmental parameters. Moreover, during seed and pollen development plants make use of RNA granules and other translational controls to underpin developmental transitions between quiescent and metabolically active stages. The economics of resource allocation over the daily light-dark cycle also include controls over cellular protein synthesis. Important new insights into translational control on cytosolic ribosomes continue to emerge from studies of translational control mechanisms in viruses. Finally, sketches of coherent signaling pathways that connect external stimuli with a translational response are emerging, anchored in part around TOR and GCN2 kinase signaling networks. These again reveal some mechanisms that are familiar and others that are different from other eukaryotes, motivating deeper studies on translational control in plants. This article is categorized under: Translation > Translation Regulation RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Ricardo A. Urquidi-Camacho
- UT-ORNL Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996
| | - Ansul Lokdarshi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology and UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996
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30
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Abt MR, Pfister B, Sharma M, Eicke S, Bürgy L, Neale I, Seung D, Zeeman SC. STARCH SYNTHASE5, a Noncanonical Starch Synthase-Like Protein, Promotes Starch Granule Initiation in Arabidopsis. THE PLANT CELL 2020; 32:2543-2565. [PMID: 32471861 PMCID: PMC7401018 DOI: 10.1105/tpc.19.00946] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/26/2020] [Accepted: 05/21/2020] [Indexed: 05/04/2023]
Abstract
What determines the number of starch granules in plastids is an enigmatic aspect of starch metabolism. Several structurally and functionally diverse proteins have been implicated in the granule initiation process in Arabidopsis (Arabidopsis thaliana), with each protein exerting a varying degree of influence. Here, we show that a conserved starch synthase-like protein, STARCH SYNTHASE5 (SS5), regulates the number of starch granules that form in Arabidopsis chloroplasts. Among the starch synthases, SS5 is most closely related to SS4, a major determinant of granule initiation and morphology. However, unlike SS4 and the other starch synthases, SS5 is a noncanonical isoform that lacks catalytic glycosyltransferase activity. Nevertheless, loss of SS5 reduces starch granule numbers that form per chloroplast in Arabidopsis, and ss5 mutant starch granules are larger than wild-type granules. Like SS4, SS5 has a conserved putative surface binding site for glucans and also interacts with MYOSIN-RESEMBLING CHLOROPLAST PROTEIN, a proposed structural protein influential in starch granule initiation. Phenotypic analysis of a suite of double mutants lacking both SS5 and other proteins implicated in starch granule initiation allows us to propose how SS5 may act in this process.
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Affiliation(s)
- Melanie R Abt
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - Barbara Pfister
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - Mayank Sharma
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - Léo Bürgy
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - Isabel Neale
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - David Seung
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, Swiss Federal Institute of Technology in Zurich, 8092 Zurich, Switzerland
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31
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Smith AM, Zeeman SC. Starch: A Flexible, Adaptable Carbon Store Coupled to Plant Growth. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:217-245. [PMID: 32075407 DOI: 10.1146/annurev-arplant-050718-100241] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Research in the past decade has uncovered new and surprising information about the pathways of starch synthesis and degradation. This includes the discovery of previously unsuspected protein families required both for processes and for the long-sought mechanism of initiation of starch granules. There is also growing recognition of the central role of leaf starch turnover in making carbon available for growth across the day-night cycle. Sophisticated systems-level control mechanisms involving the circadian clock set rates of nighttime starch mobilization that maintain a steady supply of carbon until dawn and modulate partitioning of photosynthate into starch in the light, optimizing the fraction of assimilated carbon that can be used for growth. These discoveries also uncover complexities: Results from experiments with Arabidopsis leaves in conventional controlled environments are not necessarily applicable to other organs or species or to growth in natural, fluctuating environments.
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Affiliation(s)
| | - Samuel C Zeeman
- Institute of Plant Molecular Biology, ETH Zürich, 8092 Zürich, Switzerland
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32
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Lu MZ, Snyder R, Grant J, Tegeder M. Manipulation of sucrose phloem and embryo loading affects pea leaf metabolism, carbon and nitrogen partitioning to sinks as well as seed storage pools. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:217-236. [PMID: 31520495 DOI: 10.1111/tpj.14533] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 08/11/2019] [Accepted: 09/09/2019] [Indexed: 05/03/2023]
Abstract
Seed development largely depends on the long-distance transport of sucrose from photosynthetically active source leaves to seed sinks. This source-to-sink carbon allocation occurs in the phloem and requires the loading of sucrose into the leaf phloem and, at the sink end, its import into the growing embryo. Both tasks are achieved through the function of SUT sucrose transporters. In this study, we used vegetable peas (Pisum sativum L.), harvested for human consumption as immature seeds, as our model crop and simultaneously overexpressed the endogenous SUT1 transporter in the leaf phloem and in cotyledon epidermal cells where import into the embryo occurs. Using this 'Push-and-Pull' approach, the transgenic SUT1 plants displayed increased sucrose phloem loading and carbon movement from source to sink causing higher sucrose levels in developing pea seeds. The enhanced sucrose partitioning further led to improved photosynthesis rates, increased leaf nitrogen assimilation, and enhanced source-to-sink transport of amino acids. Embryo loading with amino acids was also increased in SUT1-overexpressors resulting in higher protein levels in immature seeds. Further, transgenic plants grown until desiccation produced more seed protein and starch, as well as higher seed yields than the wild-type plants. Together, the results demonstrate that the SUT1-overexpressing plants with enhanced sucrose allocation to sinks adjust leaf carbon and nitrogen metabolism, and amino acid partitioning in order to accommodate the increased assimilate demand of growing seeds. We further provide evidence that the combined Push-and-Pull approach for enhancing carbon transport is a successful strategy for improving seed yields and nutritional quality in legumes.
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Affiliation(s)
- Ming-Zhu Lu
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Rachel Snyder
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Jan Grant
- New Zealand Institute for Plant and Food Research Ltd, Christchurch, 8140, New Zealand
| | - Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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Abstract
Synthetic biology uses living cells as the substrate for performing human-defined computations. Many current implementations of cellular computing are based on the “genetic circuit” metaphor, an approximation of the operation of silicon-based computers. Although this conceptual mapping has been relatively successful, we argue that it fundamentally limits the types of computation that may be engineered inside the cell, and fails to exploit the rich and diverse functionality available in natural living systems. We propose the notion of “cellular supremacy” to focus attention on domains in which biocomputing might offer superior performance over traditional computers. We consider potential pathways toward cellular supremacy, and suggest application areas in which it may be found. Synthetic biology uses cells as its computing substrate, often based on the genetic circuit concept. In this Perspective, the authors argue that existing synthetic biology approaches based on classical models of computation limit the potential of biocomputing, and propose that living organisms have under-exploited capabilities.
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34
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Gene networks that compensate for crosstalk with crosstalk. Nat Commun 2019; 10:4028. [PMID: 31492904 PMCID: PMC6731275 DOI: 10.1038/s41467-019-12021-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 08/12/2019] [Indexed: 12/18/2022] Open
Abstract
Crosstalk is a major challenge to engineering sophisticated synthetic gene networks. A common approach is to insulate signal-transduction pathways by minimizing molecular-level crosstalk between endogenous and synthetic genetic components, but this strategy can be difficult to apply in the context of complex, natural gene networks and unknown interactions. Here, we show that synthetic gene networks can be engineered to compensate for crosstalk by integrating pathway signals, rather than by pathway insulation. We demonstrate this principle using reactive oxygen species (ROS)-responsive gene circuits in Escherichia coli that exhibit concentration-dependent crosstalk with non-cognate ROS. We quantitatively map the degree of crosstalk and design gene circuits that introduce compensatory crosstalk at the gene network level. The resulting gene network exhibits reduced crosstalk in the sensing of the two different ROS. Our results suggest that simple network motifs that compensate for pathway crosstalk can be used by biological networks to accurately interpret environmental signals. Crosstalk between genetic circuits is a major challenge for engineering sophisticated networks. Here the authors design networks that compensate for crosstalk by integrating, not insulating, pathways.
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35
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Schreier TB, Umhang M, Lee SK, Lue WL, Shen Z, Silver D, Graf A, Müller A, Eicke S, Stadler-Waibel M, Seung D, Bischof S, Briggs SP, Kötting O, Moorhead GBG, Chen J, Zeeman SC. LIKE SEX4 1 Acts as a β-Amylase-Binding Scaffold on Starch Granules during Starch Degradation. THE PLANT CELL 2019; 31:2169-2186. [PMID: 31266901 PMCID: PMC6751131 DOI: 10.1105/tpc.19.00089] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/17/2019] [Accepted: 06/26/2019] [Indexed: 05/23/2023]
Abstract
In Arabidopsis (Arabidopsis thaliana) leaves, starch is synthesized during the day and degraded at night to fuel growth and metabolism. Starch is degraded primarily by β-amylases, liberating maltose, but this activity is preceded by glucan phosphorylation and is accompanied by dephosphorylation. A glucan phosphatase family member, LIKE SEX4 1 (LSF1), binds starch and is required for normal starch degradation, but its exact role is unclear. Here, we show that LSF1 does not dephosphorylate glucans. The recombinant dual specificity phosphatase (DSP) domain of LSF1 had no detectable phosphatase activity. Furthermore, a variant of LSF1 mutated in the catalytic cysteine of the DSP domain complemented the starch-excess phenotype of the lsf1 mutant. By contrast, a variant of LSF1 with mutations in the carbohydrate binding module did not complement lsf1 Thus, glucan binding, but not phosphatase activity, is required for the function of LSF1 in starch degradation. LSF1 interacts with the β-amylases BAM1 and BAM3, and the BAM1-LSF1 complex shows amylolytic but not glucan phosphatase activity. Nighttime maltose levels are reduced in lsf1, and genetic analysis indicated that the starch-excess phenotype of lsf1 is dependent on bam1 and bam3 We propose that LSF1 binds β-amylases at the starch granule surface, thereby promoting starch degradation.
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Affiliation(s)
- Tina B Schreier
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom
| | - Martin Umhang
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Sang-Kyu Lee
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Wei-Ling Lue
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Zhouxin Shen
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093-0380
| | - Dylan Silver
- University of Calgary, Department of Biological Sciences, Calgary, Alberta T2N 1N4, Canada
| | - Alexander Graf
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Antonia Müller
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | | | - David Seung
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Sylvain Bischof
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Steven P Briggs
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093-0380
| | - Oliver Kötting
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Greg B G Moorhead
- University of Calgary, Department of Biological Sciences, Calgary, Alberta T2N 1N4, Canada
| | - Jychian Chen
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zurich, CH-8092 Zurich, Switzerland
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Alves LC, Llerena JPP, Mazzafera P, Vicentini R. Diel oscillations in cell wall components and soluble sugars as a response to short-day in sugarcane (Saccharum sp.). BMC PLANT BIOLOGY 2019; 19:215. [PMID: 31122198 PMCID: PMC6533765 DOI: 10.1186/s12870-019-1837-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 05/17/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND Sugarcane is a tropical crop that can accumulate high concentration of sucrose in the stem as a storage carbohydrate. For that reason, sugarcane accounts for approximately 75% of all the sugar produced in the world and has become the main sugar source to produce first-generation bioethanol in Brazil. Daily rhythms cause plants to adapt and coordinate their metabolism to achieve maximum photosynthesis and carbohydrate production throughout the day. Circadian rhythms arise from the interaction of an internal oscillator and external stimuli, whereas diel rhythms occur in response to a light-dark cycle. Diel signalling contributes to synchronizing circadian rhythms to photoperiods, and levels of carbohydrates oscillate in a diel fashion. Under regular photoperiods, they are synthesized during the daytime and consumed throughout the night as an energy reserve. However, short days can induce higher rates of synthesis during daytime and lower rates of consumption in the dark. Cell wall carbohydrates are also diurnally regulated, and it has been shown that celluloses, hemicelluloses and pectin are deposited/degraded at different times of the day. To assess the diel carbohydrate profile in young sugarcane plants, we measured soluble sugars and cell wall components along a time course in plants subjected either to a regular day or short day. RESULTS Short-day influenced sucrose synthesis and cell wall components. In short-day a 44% increase in sucrose concentration was detected in the dark, but was stable during the day. Cellulose, hemicellulose and pectin also fluctuate within a 24 h interval when subjected to a short day. A 38% increase in leaf sheath cellulose was observed from the middle of the day to the first hour of the night. Leaf sheath pectin and hemicellulose also increased from the day to the night, while it decreased in leaves. CONCLUSIONS The presented data show diurnal patterns of soluble sugar metabolism together with temporal regulation of cell wall metabolism for a short day, suggesting that diel signalling has a role in how sugarcane manages sugar accumulation and partitioning. Understanding cell wall synthesis/degradation dynamics may help to improve the yield of sugarcane.
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Affiliation(s)
- Leonardo Cardoso Alves
- Bioinformatics and Systems Biology Laboratory, Department of Genetics and Evolution and Bioagents, University of Campinas, Campinas, SP Brazil
| | | | - Paulo Mazzafera
- Department of Plant Biology, University of Campinas, Campinas, SP Brazil
- Crop Science Department, College of Agriculture Luiz de Queiroz, University of São Paulo, Piracicaba, Brazil
| | - Renato Vicentini
- Bioinformatics and Systems Biology Laboratory, Department of Genetics and Evolution and Bioagents, University of Campinas, Campinas, SP Brazil
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Moraes TA, Mengin V, Annunziata MG, Encke B, Krohn N, Höhne M, Stitt M. Response of the Circadian Clock and Diel Starch Turnover to One Day of Low Light or Low CO 2. PLANT PHYSIOLOGY 2019; 179:1457-1478. [PMID: 30670603 PMCID: PMC6446786 DOI: 10.1104/pp.18.01418] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 01/09/2019] [Indexed: 05/18/2023]
Abstract
Diel starch turnover responds rapidly to changes in the light regime. We investigated if these responses require changes in the temporal dynamics of the circadian clock. Arabidopsis (Arabidopsis thaliana) was grown in a 12-h photoperiod for 19 d, shifted to three different reduced light levels or to low CO2 for one light period, and returned to growth conditions. The treatments produced widespread changes in clock transcript abundance. However, almost all of the changes were restricted to extreme treatments that led to carbon starvation and were small compared to the magnitude of the circadian oscillation. Changes included repression of EARLY FLOWERNG 4, slower decay of dusk components, and a slight phase delay at the next dawn, possibly due to abrogated Evening Complex function and sustained expression of PHYTOCHROME INTERACTING FACTORs and REVEILLEs during the night. Mobilization of starch in the night occurred in a linear manner and was paced to dawn, both in moderate treatments that did not alter clock transcripts and in extreme treatments that led to severe carbon starvation. We conclude that pacing of starch mobilization to dawn does not require retrograde carbon signaling to the transcriptional clock. On the following day, growth decreased, sugars rose, and starch accumulation was stimulated in low-light-treated plants compared to controls. This adaptive response was marked after moderate treatments and occurred independently of changes in the transcriptional clock. It is probably a time-delayed response to low-C signaling in the preceding 24-h cycle, possibly including changes in PHYTOCHROME INTERACTING FACTOR and REVEILLE expression.
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Affiliation(s)
- Thiago Alexandre Moraes
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Virginie Mengin
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Maria Grazia Annunziata
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Beatrice Encke
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Nicole Krohn
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Melanie Höhne
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
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38
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Kim J. Sugar metabolism as input signals and fuel for leaf senescence. Genes Genomics 2019; 41:737-746. [PMID: 30879182 DOI: 10.1007/s13258-019-00804-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 02/21/2019] [Indexed: 12/27/2022]
Abstract
Senescence in plants is an active and acquired developmental process that occurs at the last developmental stage during the life cycle of a plant. Leaf senescence is a relatively slow process, which is characterized by loss of photosynthetic activity and breakdown of macromolecules, to compensate for reduced energy production. Sugars, major photosynthetic assimilates, are key substrates required for cellular respiration to produce intermediate sources of energy and reducing power, which are known to be essential for the maintenance of cellular processes during senescence. In addition, sugars play roles as signaling molecules to facilitate a wide range of developmental processes as metabolic sensors. However, the roles of sugar during the entire period of senescence remain fragmentary. The purpose of the present review was to examine and explore changes in production, sources, and functions of sugars during leaf senescence. Further, the review explores the current state of knowledge on how sugars mediate the onset or progression of leaf senescence. Progress in the area would facilitate the determination of more sophisticated ways of manipulating the senescence process in plants and offer insights that guide efforts to maintain nutrients in leafy plants during postharvest storage.
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Affiliation(s)
- Jeongsik Kim
- Faculty of Science Education, Jeju National University, Jeju, 63243, Republic of Korea.
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39
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Flis A, Mengin V, Ivakov AA, Mugford ST, Hubberten HM, Encke B, Krohn N, Höhne M, Feil R, Hoefgen R, Lunn JE, Millar AJ, Smith AM, Sulpice R, Stitt M. Multiple circadian clock outputs regulate diel turnover of carbon and nitrogen reserves. PLANT, CELL & ENVIRONMENT 2019; 42:549-573. [PMID: 30184255 DOI: 10.1111/pce.13440] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 08/27/2018] [Accepted: 08/31/2018] [Indexed: 05/09/2023]
Abstract
Plants accumulate reserves in the daytime to support growth at night. Circadian regulation of diel reserve turnover was investigated by profiling starch, sugars, glucose 6-phosphate, organic acids, and amino acids during a light-dark cycle and after transfer to continuous light in Arabidopsis wild types and in mutants lacking dawn (lhy cca1), morning (prr7 prr9), dusk (toc1, gi), or evening (elf3) clock components. The metabolite time series were integrated with published time series for circadian clock transcripts to identify circadian outputs that regulate central metabolism. (a) Starch accumulation was slower in elf3 and prr7 prr9. It is proposed that ELF3 positively regulates starch accumulation. (b) Reducing sugars were high early in the T-cycle in elf3, revealing that ELF3 negatively regulates sucrose recycling. (c) The pattern of starch mobilization was modified in all five mutants. A model is proposed in which dawn and dusk/evening components interact to pace degradation to anticipated dawn. (d) An endogenous oscillation of glucose 6-phosphate revealed that the clock buffers metabolism against the large influx of carbon from photosynthesis. (e) Low levels of organic and amino acids in lhy cca1 and high levels in prr7 prr9 provide evidence that the dawn components positively regulate the accumulation of amino acid reserves.
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Affiliation(s)
- Anna Flis
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Virginie Mengin
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Alexander A Ivakov
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Sam T Mugford
- John Innes Centre, Norwich Research Park, Norwich, UK
| | | | - Beatrice Encke
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Nicole Krohn
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Melanie Höhne
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Regina Feil
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Rainer Hoefgen
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Andrew J Millar
- SynthSys and School of Biological Sciences, C.H. Waddington Building, University of Edinburgh, Edinburgh, UK
| | | | - Ronan Sulpice
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
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40
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Webb AAR, Seki M, Satake A, Caldana C. Continuous dynamic adjustment of the plant circadian oscillator. Nat Commun 2019; 10:550. [PMID: 30710080 PMCID: PMC6358598 DOI: 10.1038/s41467-019-08398-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/09/2019] [Indexed: 11/08/2022] Open
Abstract
The clockwork of plant circadian oscillators has been resolved through investigations in Arabidopsis thaliana. The circadian oscillator is an important regulator of much of plant physiology, though many of the mechanisms are unclear. New findings demonstrate that the oscillator adjusts phase and period in response to abiotic and biotic signals, providing insight in to how the plant circadian oscillator integrates with the biology of the cell and entrains to light, dark and temperature cycles. We propose that the plant circadian oscillator is dynamically plastic, in constant adjustment, rather than being an isolated clock impervious to cellular events.
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Affiliation(s)
- Alex A R Webb
- Department of Plant Sciences, Downing Street, Cambridge, CB3 0LJ, UK.
| | - Motohide Seki
- Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minamiku, Fukuoka, 815-8540, Japan
| | - Akiko Satake
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, 819-0395, Japan
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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41
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Zakhartsev M. Using a Multi-compartmental Metabolic Model to Predict Carbon Allocation in Arabidopsis thaliana. Methods Mol Biol 2019; 2014:345-369. [PMID: 31197808 DOI: 10.1007/978-1-4939-9562-2_27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The molecular mechanism of loading/unloading of sucrose into/from the phloem plays an important role in sucrose translocation among plant tissues. Perturbation of this mechanism results in growth phenotypes of a plant. In order to better understand the coupling of sucrose translocation with metabolic processes a multi-compartmental metabolic network of Arabidopsis thaliana was reconstructed and optimized with respect to biomass growth, both in light and in dark conditions. The model can be used to perform flux balance analysis of metabolic fluxes through the central carbon metabolism and catabolic and anabolic pathways. Balances and turnover of energy (ATP/ADP) and redox metabolites (NAD(P)H/NAD(P)) as well as proton concentrations in different compartments can be estimated. Importantly, the model can be used to quantify the translocation of sucrose from source to sink tissues through phloem in association with an integral balance of protons, which in turn is defined by the operational modes of the energy metabolism (light and dark conditions). This chapter describes how a multi-compartmental model to predict carbon allocation is constructed and used.
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Affiliation(s)
- Maksim Zakhartsev
- Centre for Integrative Genetics, Norwegian University of Life Sciences, Ås, Norway.
- Plant Systems Biology, University of Hohenheim, Stuttgart, Germany.
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42
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Vandromme C, Spriet C, Dauvillée D, Courseaux A, Putaux JL, Wychowski A, Krzewinski F, Facon M, D'Hulst C, Wattebled F. PII1: a protein involved in starch initiation that determines granule number and size in Arabidopsis chloroplast. THE NEW PHYTOLOGIST 2019; 221:356-370. [PMID: 30055112 DOI: 10.1111/nph.15356] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 06/17/2018] [Indexed: 06/08/2023]
Abstract
The initiation of starch granule formation is still poorly understood. However, the soluble starch synthase 4 (SS4) appears to be a major component of this process since it is required to synthesize the correct number of starch granules in the chloroplasts of Arabidopsis thaliana plants. A yeast two-hybrid screen allowed the identification of several putative SS4 interacting partners. We identified the product of At4g32190 locus as a chloroplast-targeted PROTEIN INVOLVED IN STARCH INITIATION (named PII1). Arabidopsis mutants devoid of PII1 display an alteration of the starch initiation process and accumulate, on average, one starch granule per plastid instead of the five to seven granules found in plastids of wild-type plants. These granules are larger than in wild-type, and they remain flat and lenticular. pii1 mutants display wild-type growth rates and accumulate standard starch amounts. Moreover, starch characteristics, such as amylopectin chain length distribution, remain unchanged. Our results reveal the involvement of PII1 in the starch priming process in Arabidopsis leaves through interaction with SS4.
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Affiliation(s)
- Camille Vandromme
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Corentin Spriet
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - David Dauvillée
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Adeline Courseaux
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Jean-Luc Putaux
- Université Grenoble Alpes, CNRS, CERMAV, F-38000, Grenoble, France
| | - Adeline Wychowski
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Frédéric Krzewinski
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Maud Facon
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Christophe D'Hulst
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Fabrice Wattebled
- Univ. Lille, CNRS, UMR8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
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43
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Guendel A, Rolletschek H, Wagner S, Muszynska A, Borisjuk L. Micro Imaging Displays the Sucrose Landscape within and along Its Allocation Pathways. PLANT PHYSIOLOGY 2018; 178:1448-1460. [PMID: 30275056 PMCID: PMC6288747 DOI: 10.1104/pp.18.00947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/18/2018] [Indexed: 05/05/2023]
Abstract
Sucrose (Suc) is the major transport sugar in plants and plays a primary role as an energy source and signal in adaptive and stress responses. An ability to quantify Suc over time and space would serve to advance our understanding of these important processes. Current technologies used for Suc mapping are unable to quantitatively visualize its distribution within tissues. Here, we present an infrared-based microspectroscopic method that allows for the quantitative visualization of Suc at a microscopic level of resolution (∼12 µm). This method can successfully model the sugar concentration in individual vascular bundles and within a complex organ such as the stem, leaf, or seed. The sensitivity of the assay ranges from 20 to 1,000 mm We applied this method to the cereal crop barley (Hordeum vulgare) and the model plant Arabidopsis (Arabidopsis thaliana) to highlight the potential of the procedure for resolving the spatial distribution of metabolites. We also discuss the relevance of the method for studies on carbon allocation and storage in the context of crop improvement.
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Affiliation(s)
- André Guendel
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
| | - Hardy Rolletschek
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
| | - Steffen Wagner
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
| | - Aleksandra Muszynska
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
| | - Ljudmilla Borisjuk
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
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44
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Waveforms of molecular oscillations reveal circadian timekeeping mechanisms. Commun Biol 2018; 1:207. [PMID: 30511021 PMCID: PMC6255756 DOI: 10.1038/s42003-018-0217-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 11/01/2018] [Indexed: 11/12/2022] Open
Abstract
Circadian clocks play a pivotal role in orchestrating numerous physiological and developmental events. Waveform shapes of the oscillations of protein abundances can be informative about the underlying biochemical processes of circadian clocks. We derive a mathematical framework where waveforms do reveal hidden biochemical mechanisms of circadian timekeeping. We find that the cost of synthesizing proteins with particular waveforms can be substantially reduced by rhythmic protein half-lives over time, as supported by previous plant and mammalian data, as well as our own seedling experiment. We also find that previously enigmatic, cyclic expression of positive arm components within the mammalian and insect clocks allows both a broad range of peak time differences between protein waveforms and the symmetries of the waveforms about the peak times. Such various peak-time differences may facilitate tissue-specific or developmental stage-specific multicellular processes. Our waveform-guided approach can be extended to various biological oscillators, including cell-cycle and synthetic genetic oscillators. Hang-Hyun Jo et al. derive a mathematical framework for analyzing circadian clock waveforms. Using data from plants and animals, they find that waveforms of clock protein profiles provide important information about the biochemical mechanisms of circadian timekeeping.
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45
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Yoshida T, Anjos LD, Medeiros DB, Araújo WL, Fernie AR, Daloso DM. Insights into ABA-mediated regulation of guard cell primary metabolism revealed by systems biology approaches. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 146:37-49. [PMID: 30447225 DOI: 10.1016/j.pbiomolbio.2018.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/02/2018] [Accepted: 11/13/2018] [Indexed: 01/08/2023]
Abstract
Despite the fact that guard cell abscisic acid (ABA) signalling pathway is well documented, our understanding concerning how and to which extent ABA regulates guard cell metabolism remains fragmentary. Here we have adopted different systems approaches to investigate how ABA modulates guard cell central metabolism by providing genes that are possibly ABA-regulated. By using previous published Arabidopsis guard cell transcript profiling data, we carried out an extensive co-expression network analysis using ABA-related genes and those related to the metabolism and transport of sugars, starch and organic acids. Next, we investigated the presence of ABA responsive elements (ABRE) in the promoter of genes that are highly expressed in guard cells, responsive to ABA and co-expressed with ABA-related genes. Together, these analyses indicated that 44 genes are likely regulated by ABA and 8 of them are highly expressed in guard cells in both the presence and absence of ABA, including genes of the tricarboxylic acid cycle and those related to sucrose and hexose transport and metabolism. It seems likely that ABA may modulate both sucrose transport through guard cell plasma membrane and sucrose metabolism within guard cells. In this context, genes associated with sucrose synthase, sucrose phosphate synthase, trehalose-6-phosphate, invertase, UDP-glucose epimerase/pyrophosphorylase and different sugar transporters contain ABRE in their promoter and are thus possibly ABA regulated. Although validation experiments are required, our study highlights the importance of systems biology approaches to drive new hypothesis and to unravel genes and pathways that are regulated by ABA in guard cells.
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Affiliation(s)
- Takuya Yoshida
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Golm, 14476, Germany.
| | - Letícia Dos Anjos
- Departamento de Biologia Vegetal, Universidade Federal de Lavras, Lavras, Minas Gerais, 62700-000, Brazil
| | - David B Medeiros
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Golm, 14476, Germany; Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Wagner L Araújo
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Alisdair R Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Golm, 14476, Germany
| | - Danilo M Daloso
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Ceará, 60451-970, Brazil.
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46
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Basso V, De Freitas Pereira M, Maillard F, Mallerman J, Mangeot-Peter L, Zhang F, Bonnot C. Facing global change: the millennium challenge for plant scientists: 41 st New Phytologist Symposium 'Plant sciences for the future', Nancy, France, April 2018. THE NEW PHYTOLOGIST 2018; 220:25-29. [PMID: 30156020 DOI: 10.1111/nph.15376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Veronica Basso
- Laboratoire d'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystemes Forestiers (LabEx ARBRE), UMR Interactions Arbres/Microorganismes (IAM) 1136, INRA, Université de Lorraine, Centre INRA Grand-Est, Champenoux, 54280, France
| | | | - François Maillard
- Laboratoire d'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystemes Forestiers (LabEx ARBRE), UMR Interactions Arbres/Microorganismes (IAM) 1136, INRA, Université de Lorraine, Centre INRA Grand-Est, Champenoux, 54280, France
| | - Julieta Mallerman
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - Lauralie Mangeot-Peter
- Laboratoire d'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystemes Forestiers (LabEx ARBRE), UMR Interactions Arbres/Microorganismes (IAM) 1136, INRA, Université de Lorraine, Centre INRA Grand-Est, Champenoux, 54280, France
| | - Feng Zhang
- Laboratoire d'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystemes Forestiers (LabEx ARBRE), UMR Interactions Arbres/Microorganismes (IAM) 1136, INRA, Université de Lorraine, Centre INRA Grand-Est, Champenoux, 54280, France
| | - Clémence Bonnot
- Laboratoire d'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystemes Forestiers (LabEx ARBRE), UMR Interactions Arbres/Microorganismes (IAM) 1136, INRA, Université de Lorraine, Centre INRA Grand-Est, Champenoux, 54280, France
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47
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Annunziata MG, Apelt F, Carillo P, Krause U, Feil R, Koehl K, Lunn JE, Stitt M. Response of Arabidopsis primary metabolism and circadian clock to low night temperature in a natural light environment. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4881-4895. [PMID: 30053131 PMCID: PMC6137998 DOI: 10.1093/jxb/ery276] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 07/09/2018] [Indexed: 05/18/2023]
Abstract
Plants are exposed to varying irradiance and temperature within a day and from day to day. We previously investigated metabolism in a temperature-controlled greenhouse at the spring equinox on both a cloudy and a sunny day [daily light integral (DLI) of 7 mol m-2 d-1 and 12 mol m-2 d-1]. Diel metabolite profiles were largely captured in sinusoidal simulations at similar DLIs in controlled-environment chambers, except that amino acids were lower in natural light regimes. We now extend the DLI12 study by investigating metabolism in a natural light regime with variable temperature including cool nights. Starch was not completely turned over, anthocyanins and proline accumulated, and protein content rose. Instead of decreasing, amino acid content rose. Connectivity in central metabolism, which decreased in variable light, was not further weakened by variable temperature. We propose that diel metabolism operates better when light and temperature are co-varying. We also compared transcript abundance of 10 circadian clock genes in this temperature-variable regime with the temperature-controlled natural and sinusoidal light regimes. Despite temperature compensation, peak timing and abundance for dawn- and day-phased genes and GIGANTEA were slightly modified in the variable temperature treatment. This may delay dawn clock activity until the temperature rises enough to support rapid metabolism and photosynthesis.
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Affiliation(s)
| | - Federico Apelt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Petronia Carillo
- University of Campania ‘Luigi Vanvitelli’, Via Vivaldi, Caserta, Italy
| | - Ursula Krause
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Regina Feil
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Karin Koehl
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
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dos Anjos L, Pandey PK, Moraes TA, Feil R, Lunn JE, Stitt M. Feedback regulation by trehalose 6-phosphate slows down starch mobilization below the rate that would exhaust starch reserves at dawn in Arabidopsis leaves. PLANT DIRECT 2018; 2:e00078. [PMID: 31245743 PMCID: PMC6508811 DOI: 10.1002/pld3.78] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 06/04/2018] [Accepted: 06/26/2018] [Indexed: 05/02/2023]
Abstract
Trehalose 6-phosphate (Tre6P), a sucrose signaling metabolite, inhibits transitory starch breakdown in Arabidopsis (Arabidopsis thaliana) leaves and potentially links starch turnover to leaf sucrose status and demand from sink organs (Plant Physiology, 163, 2013, 1142). To investigate this relationship further, we compared diel patterns of starch turnover in ethanol-inducible Tre6P synthase (iTPS) lines, which have high Tre6P and low sucrose after induction, with those in sweet11;12 sucrose export mutants, which accumulate sucrose in their leaves and were predicted to have high Tre6P. Short-term changes in irradiance were used to investigate whether the strength of inhibition by Tre6P depends on starch levels. sweet11;12 mutants had twofold higher levels of Tre6P and restricted starch mobilization. The relationship between Tre6P and starch mobilization was recapitulated in iTPS lines, pointing to a dominant role for Tre6P in feedback regulation of starch mobilization. Tre6P restricted mobilization across a wide range of conditions. However, there was no correlation between the level of Tre6P and the absolute rate of starch mobilization. Rather, Tre6P depressed the rate of mobilization below that required to exhaust starch at dawn, leading to incomplete use of starch. It is discussed how Tre6P interacts with the clock to set the rate of starch mobilization.
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Affiliation(s)
- Letícia dos Anjos
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGolmGermany
- Universidade Federal do CearáFortalezaBrazil
| | - Prashant Kumar Pandey
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGolmGermany
- Present address:
National Research Council Canada (NRC‐CNRC)110 Gymnasium PlaceSaskatoonSaskatchewanS7N 0W9Canada
| | | | - Regina Feil
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGolmGermany
| | - John E. Lunn
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGolmGermany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGolmGermany
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Seung D, Schreier TB, Bürgy L, Eicke S, Zeeman SC. Two Plastidial Coiled-Coil Proteins Are Essential for Normal Starch Granule Initiation in Arabidopsis. THE PLANT CELL 2018; 30:1523-1542. [PMID: 29866647 PMCID: PMC6096604 DOI: 10.1105/tpc.18.00219] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/07/2018] [Accepted: 06/01/2018] [Indexed: 05/18/2023]
Abstract
The mechanism of starch granule initiation in chloroplasts is not fully understood. Here, we aimed to build on our recent discovery that PROTEIN TARGETING TO STARCH (PTST) family members, PTST2 and PTST3, are key players in starch granule initiation, by identifying and characterizing additional proteins involved in the process in Arabidopsis thaliana chloroplasts. Using immunoprecipitation and mass spectrometry, we demonstrate that PTST2 interacts with two plastidial coiled-coil proteins. Surprisingly, one of the proteins is the thylakoid-associated MAR BINDING FILAMENT-LIKE PROTEIN1 (MFP1), which was proposed to bind plastid nucleoids. The other protein, MYOSIN-RESEMBLING CHLOROPLAST PROTEIN (MRC), contains long coiled coils and no known domains. Whereas wild-type chloroplasts contained multiple starch granules, only one large granule was observed in most chloroplasts of the mfp1 and mrc mutants. The mfp1 mrc double mutant had a higher proportion of chloroplasts containing no visible granule than either single mutant and accumulated ADP-glucose, the substrate for starch synthesis. PTST2 was partially associated with the thylakoid membranes in wild-type plants, and fluorescently tagged PTST2 was located in numerous discrete patches within the chloroplast in which MFP1 was also located. In the mfp1 mutant, PTST2 was not associated with the thylakoids and formed discrete puncta, suggesting that MFP1 is necessary for normal PTST2 localization. Overall, we reveal that proper granule initiation requires the presence of MFP1 and MRC, and the correct location of PTST2.
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Affiliation(s)
- David Seung
- Institute of Molecular Plant Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Tina B Schreier
- Institute of Molecular Plant Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Léo Bürgy
- Institute of Molecular Plant Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zurich, 8092 Zurich, Switzerland
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Dong S, Zhang J, Beckles DM. A pivotal role for starch in the reconfiguration of 14C-partitioning and allocation in Arabidopsis thaliana under short-term abiotic stress. Sci Rep 2018; 8:9314. [PMID: 29915332 PMCID: PMC6006365 DOI: 10.1038/s41598-018-27610-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/31/2018] [Indexed: 11/09/2022] Open
Abstract
Plant carbon status is optimized for normal growth but is affected by abiotic stress. Here, we used 14C-labeling to provide the first holistic picture of carbon use changes during short-term osmotic, salinity, and cold stress in Arabidopsis thaliana. This could inform on the early mechanisms plants use to survive adverse environment, which is important for efficient agricultural production. We found that carbon allocation from source to sinks, and partitioning into major metabolite pools in the source leaf, sink leaves and roots showed both conserved and divergent responses to the stresses examined. Carbohydrates changed under all abiotic stresses applied; plants re-partitioned 14C to maintain sugar levels under stress, primarily by reducing 14C into the storage compounds in the source leaf, and decreasing 14C into the pools used for growth processes in the roots. Salinity and cold increased 14C-flux into protein, but as the stress progressed, protein degradation increased to produce amino acids, presumably for osmoprotection. Our work also emphasized that stress regulated the carbon channeled into starch, and its metabolic turnover. These stress-induced changes in starch metabolism and sugar export in the source were partly accompanied by transcriptional alteration in the T6P/SnRK1 regulatory pathway that are normally activated by carbon starvation.
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Affiliation(s)
- Shaoyun Dong
- Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA, 95616, USA
| | - Joshua Zhang
- Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA, 95616, USA
| | - Diane M Beckles
- Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA, 95616, USA.
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