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Silverstein MR, Bhatnagar JM, Segrè D. Metabolic complexity drives divergence in microbial communities. Nat Ecol Evol 2024; 8:1493-1504. [PMID: 38956426 DOI: 10.1038/s41559-024-02440-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 05/14/2024] [Indexed: 07/04/2024]
Abstract
Microbial communities are shaped by environmental metabolites, but the principles that govern whether different communities will converge or diverge in any given condition remain unknown, posing fundamental questions about the feasibility of microbiome engineering. Here we studied the longitudinal assembly dynamics of a set of natural microbial communities grown in laboratory conditions of increasing metabolic complexity. We found that different microbial communities tend to become similar to each other when grown in metabolically simple conditions, but they diverge in composition as the metabolic complexity of the environment increases, a phenomenon we refer to as the divergence-complexity effect. A comparative analysis of these communities revealed that this divergence is driven by community diversity and by the assortment of specialist taxa capable of degrading complex metabolites. An ecological model of community dynamics indicates that the hierarchical structure of metabolism itself, where complex molecules are enzymatically degraded into progressively simpler ones that then participate in cross-feeding between community members, is necessary and sufficient to recapitulate our experimental observations. In addition to helping understand the role of the environment in community assembly, the divergence-complexity effect can provide insight into which environments support multiple community states, enabling the search for desired ecosystem functions towards microbiome engineering applications.
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Affiliation(s)
- Michael R Silverstein
- Bioinformatics Program, Faculty of Computing and Data Science, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA, USA
| | - Jennifer M Bhatnagar
- Bioinformatics Program, Faculty of Computing and Data Science, Boston University, Boston, MA, USA
- Department of Biology, Boston University, Boston, MA, USA
| | - Daniel Segrè
- Bioinformatics Program, Faculty of Computing and Data Science, Boston University, Boston, MA, USA.
- Biological Design Center, Boston University, Boston, MA, USA.
- Department of Biology, Boston University, Boston, MA, USA.
- Department of Biomedical Engineering and Department of Physics, Boston University, Boston, MA, USA.
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2
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Chustecki JM, Johnston IG. Collective mitochondrial dynamics resolve conflicting cellular tensions: From plants to general principles. Semin Cell Dev Biol 2024; 156:253-265. [PMID: 38043948 DOI: 10.1016/j.semcdb.2023.09.005] [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] [Received: 06/05/2023] [Revised: 08/18/2023] [Accepted: 09/15/2023] [Indexed: 12/05/2023]
Abstract
Mitochondria play diverse and essential roles in eukaryotic cells, and plants are no exception. Plant mitochondria have several differences from their metazoan and fungal cousins: they often exist in a fragmented state, move rapidly on actin rather than microtubules, have many plant-specific metabolic features and roles, and usually contain only a subset of the complete mtDNA genome, which itself undergoes frequent recombination. This arrangement means that exchange and complementation is essential for plant mitochondria, and recent work has begun to reveal how their collective dynamics and resultant "social networks" of encounters support this exchange, connecting plant mitochondria in time rather than in space. This review will argue that this social network perspective can be extended to a "societal network", where mitochondrial dynamics are an essential part of the interacting cellular society of organelles and biomolecules. Evidence is emerging that mitochondrial dynamics allow optimal resolutions to competing cellular priorities; we will survey this evidence and review potential future research directions, highlighting that plant mitochondria can help reveal and test principles that apply across other kingdoms of life. In parallel with this fundamental cell biology, we also highlight the translational "One Health" importance of plant mitochondrial behaviour - which is exploited in the production of a vast amount of crops consumed worldwide - and the potential for multi-objective optimisation to understand and rationally re-engineer the evolved resolutions to these tensions.
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Affiliation(s)
- Joanna M Chustecki
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Iain G Johnston
- Department of Mathematics, University of Bergen, Bergen, Norway; Computational Biology Unit, University of Bergen, Bergen, Norway.
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3
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Jia L, Tang Y, Tian K, Ai W, Shang W, Wu H. Effects of hypobaria, hyperoxia, and nitrogen form on the growth and nutritional quality of lettuce. LIFE SCIENCES IN SPACE RESEARCH 2024; 40:44-50. [PMID: 38245347 DOI: 10.1016/j.lssr.2023.12.001] [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: 04/02/2023] [Revised: 10/14/2023] [Accepted: 12/12/2023] [Indexed: 01/22/2024]
Abstract
The objectives of this research were to investigate the impact of hypobaria, hyperoxia, and nitrogen form on the growth and nutritional quality of plants. Pre-culture 20-day-old lettuce (Lactuca sativa L. var. Rome) seedlings grew for 25 days under three levels of total atmospheric pressure (101, 54, and 30 kPa), two levels of oxygen partial pressure (21 and 28 kPa), and two forms of nitrogen (NO3N and NH4N). The ratios of NO3N to NH4N included 3: 1, 4: 0, 2: 2, and 0: 4. The nitrogen quantity included two levels, i.e. N1, 0.1 g N kg-1 dry matrix and N2, 0.2 g N kg-1 dry matrix. The growth status of lettuce plants in different treatments differentiated markedly. Regardless of the nitrogen factor, the growth status of lettuce plants treated with total atmospheric pressure/oxygen partial pressure at 54/21 was equivalent to the treatment of 101/21. Under the hypobaric condition (54 kPa), compared with 21 kPa oxygen partial pressure, hyperoxia (28 kPa) significantly inhibited the growth of lettuce plants and the biomass (fresh weight) decreased by 60.9%-69.9% compared with that under 101/21 treatment. At the N1 level, the sequence of the biomass of lettuce plants supplied with different ratios of NO3N to NH4N was 3: 1 > 4: 0 > 2: 2 > 0: 4, and there were higher concentrations of chlorophyll and carotenoid of lettuce plants supplied with the higher ratio of NO3 to NH4. At the N2 level, the effects of different ratios of NO3N to NH4N on lettuce plants were similar to those at the N1 level. The high nitrogen (N2) promoted the growth of lettuce plants such as 54/21/N2 treatments. Both form and nitrogen level did not affect the stress resistance of lettuce plants. Hypobaria (54 kPa) increased the contents of N, P, and K and hyperoxia (28 kPa) decreased the content of organic carbon in lettuce plants. The high nitrogen (N2) improved the content of total N and the N uptake. The ratios of NO3N to NH4N were 4: 0 and 3: 1, lettuce could absorb and utilize N effectively. This study demonstrated that hyperoxia (28 kPa) inhibited the growth of lettuce plants under the hypobaric condition (54 kPa), and high level of nitrogen (0.2 g N kg-1 dry matrix) and NO3N: NH4N at 3: 1 markedly enhanced the growth, the contents of mineral elements and the nutritional quality of lettuce plants.
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Affiliation(s)
- Linwei Jia
- College of Environment and Resources, Xiangtan University, Xiangtan 411100, China; National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China
| | - Yongkang Tang
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China.
| | - Ke Tian
- College of Environment and Resources, Xiangtan University, Xiangtan 411100, China
| | - Weidang Ai
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China
| | - Wenjin Shang
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China
| | - Hao Wu
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China
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4
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Hickey K, Nazarov T, Smertenko A. Organellomic gradients in the fourth dimension. PLANT PHYSIOLOGY 2023; 193:98-111. [PMID: 37243543 DOI: 10.1093/plphys/kiad310] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/11/2023] [Indexed: 05/29/2023]
Abstract
Organelles function as hubs of cellular metabolism and elements of cellular architecture. In addition to 3 spatial dimensions that describe the morphology and localization of each organelle, the time dimension describes complexity of the organelle life cycle, comprising formation, maturation, functioning, decay, and degradation. Thus, structurally identical organelles could be biochemically different. All organelles present in a biological system at a given moment of time constitute the organellome. The homeostasis of the organellome is maintained by complex feedback and feedforward interactions between cellular chemical reactions and by the energy demands. Synchronized changes of organelle structure, activity, and abundance in response to environmental cues generate the fourth dimension of plant polarity. Temporal variability of the organellome highlights the importance of organellomic parameters for understanding plant phenotypic plasticity and environmental resiliency. Organellomics involves experimental approaches for characterizing structural diversity and quantifying the abundance of organelles in individual cells, tissues, or organs. Expanding the arsenal of appropriate organellomics tools and determining parameters of the organellome complexity would complement existing -omics approaches in comprehending the phenomenon of plant polarity. To highlight the importance of the fourth dimension, this review provides examples of organellome plasticity during different developmental or environmental situations.
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Affiliation(s)
- Kathleen Hickey
- Institute of Biological Chemistry, College of Agricultural, Human, and Natural Resources Sciences, Washington State University, Pullman, 99164 WA, USA
| | - Taras Nazarov
- Institute of Biological Chemistry, College of Agricultural, Human, and Natural Resources Sciences, Washington State University, Pullman, 99164 WA, USA
| | - Andrei Smertenko
- Institute of Biological Chemistry, College of Agricultural, Human, and Natural Resources Sciences, Washington State University, Pullman, 99164 WA, USA
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Midorikawa K, Tateishi A, Toyooka K, Sato M, Imai T, Kodama Y, Numata K. Three-dimensional nanoscale analysis of light-dependent organelle changes in Arabidopsis mesophyll cells. PNAS NEXUS 2022; 1:pgac225. [PMID: 36712360 PMCID: PMC9802074 DOI: 10.1093/pnasnexus/pgac225] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 09/15/2022] [Accepted: 10/01/2022] [Indexed: 11/06/2022]
Abstract
Different organelles function coordinately in numerous intracellular processes. Photorespiration incidental to photosynthetic carbon fixation is organized across three subcellular compartments: chloroplasts, peroxisomes, and mitochondria. Under light conditions, these three organelles often form a ternary organellar complex in close proximity, suggesting a connection with metabolism during photorespiration. However, due to the heterogeneity of intercellular organelle localization and morphology, organelles' responses to changes in the external environment remain poorly understood. Here, we used array tomography by field emission scanning electron microscopy to image organelles inside the whole plant cell at nanometer resolution, generating a three-dimensional (3D) spatial map of the light-dependent positioning of chloroplasts, peroxisomes, nuclei, and vacuoles. Our results show, in light-treated cells, the volume of peroxisomes increased, and mitochondria were simplified. In addition, the population of free organelles decreased, and the ternary complex centered on chloroplasts increased. Moreover, our results emphasized the expansion of the proximity area rather than the increase in the number of proximity sites interorganelles. All of these phenomena were quantified for the first time on the basis of nanoscale spatial maps. In summary, we provide the first 3D reconstruction of Arabidopsis mesophyll cells, together with nanoscale quantified organelle morphology and their positioning via proximity areas, and then evidence of their light-dependent changes.
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Affiliation(s)
- Keiko Midorikawa
- Biomacromoleules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan,Center for Bioscience Research and Education, Utsunomiya University, Tochigi 321-8505, Japan
| | - Ayaka Tateishi
- Biomacromoleules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan,Department of Material Chemistry, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan
| | - Kiminori Toyooka
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku Yokohama, Kanagawa 230-0045, Japan
| | - Mayuko Sato
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku Yokohama, Kanagawa 230-0045, Japan
| | - Takuto Imai
- Biomacromoleules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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6
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Tarasenko TA, Koulintchenko MV. Heterogeneity of the Mitochondrial Population in Cells of Plants and Other Organisms. Mol Biol 2022. [DOI: 10.1134/s0026893322020157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Fukushima S, Akita K, Takagi T, Kobayashi K, Moritoki N, Sugaya H, Arimura SI, Kuroiwa H, Kuroiwa T, Nagata N. Existence of giant mitochondria-containing sheet structures lacking cristae and matrix in the etiolated cotyledon of Arabidopsis thaliana. PROTOPLASMA 2022; 259:731-742. [PMID: 34417661 PMCID: PMC9010340 DOI: 10.1007/s00709-021-01696-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Mitochondria are essential organelles involved in the production and supply of energy in eukaryotic cells. Recently, the use of serial section scanning electron microscopy (S3EM) has allowed accurate three-dimensional (3D) reconstructed images of even complex organelle structures. Using this method, ultrathin sections of etiolated cotyledons were observed 4 days after germination of Arabidopsis thaliana in the dark, and giant mitochondria were found. To exclude the possibility of chemical fixation artifacts, this study confirmed the presence of giant mitochondria in high-pressure frozen samples. The 3D reconstructed giant mitochondria had a complex structure that included not only the elongated region but also the flattened shape of a disk. It contained the characteristic sheet structure, and the sheet lacked cristae and matrix but consisted of outer and inner membranes. Whether this phenomenon could be observed in living cells was investigated using the transformant with mitochondrial matrix expressing green fluorescent protein. Small globular mitochondria observed in light-treated samples were also represented in etiolated cotyledons. Although no giant mitochondria were observed in light-treated samples, they were found in the dark 3 days after germination and rapidly increased in number on the fourth day. Therefore, giant mitochondria were observed only in dark samples. These findings were supported by electron microscopy results.
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Affiliation(s)
- Saki Fukushima
- Division of Material and Biological Sciences, Graduate School of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Kae Akita
- Department of Chemical Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Tomoko Takagi
- Department of Chemical Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan
- Laboratory of Electron Microscopy, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Keiko Kobayashi
- Department of Chemical Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Nobuko Moritoki
- Laboratory of Electron Microscopy, Japan Women's University, Bunkyo-ku, Tokyo, Japan
- Electron Microscope Laboratory, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Hajime Sugaya
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shin-Ichi Arimura
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Haruko Kuroiwa
- Department of Chemical Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Tsuneyoshi Kuroiwa
- Department of Chemical Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Noriko Nagata
- Division of Material and Biological Sciences, Graduate School of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan.
- Department of Chemical Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, Japan.
- Laboratory of Electron Microscopy, Japan Women's University, Bunkyo-ku, Tokyo, Japan.
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8
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Kimata Y, Higaki T, Kurihara D, Ando N, Matsumoto H, Higashiyama T, Ueda M. Mitochondrial dynamics and segregation during the asymmetric division of Arabidopsis zygotes. QUANTITATIVE PLANT BIOLOGY 2020; 1:e3. [PMID: 37077329 PMCID: PMC10095797 DOI: 10.1017/qpb.2020.4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/03/2020] [Accepted: 09/25/2020] [Indexed: 05/02/2023]
Abstract
The zygote is the first cell of a multicellular organism. In most angiosperms, the zygote divides asymmetrically to produce an embryo-precursor apical cell and a supporting basal cell. Zygotic division should properly segregate symbiotic organelles, because they cannot be synthesized de novo. In this study, we revealed the real-time dynamics of the principle source of ATP biogenesis, mitochondria, in Arabidopsis thaliana zygotes using live-cell observations and image quantifications. In the zygote, the mitochondria formed the extended structure associated with the longitudinal array of actin filaments (F-actins) and were polarly distributed along the apical-basal axis. The mitochondria were then temporally fragmented during zygotic division, and the resulting apical cells inherited mitochondria at higher concentration compared to the basal cells. Further observation of postembryonic organs showed that these mitochondrial behaviours are characteristic of the zygote. Overall, our results showed that the zygote has spatiotemporal regulation that unequally distributes the mitochondria.
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Affiliation(s)
- Yusuke Kimata
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Takumi Higaki
- International Research Organization for Advanced Science and Technology (IROAST), Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto860-8555, Japan
| | - Daisuke Kurihara
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
- JST, PRESTO, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Naoe Ando
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Hikari Matsumoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Tetsuya Higashiyama
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo113-0033, Japan
| | - Minako Ueda
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8578, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Author for correspondence: M. Ueda, Tel.: +81 22-795-6713; E-mail:
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9
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Johnston IG. Tension and Resolution: Dynamic, Evolving Populations of Organelle Genomes within Plant Cells. MOLECULAR PLANT 2019; 12:764-783. [PMID: 30445187 DOI: 10.1016/j.molp.2018.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/25/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Mitochondria and plastids form dynamic, evolving populations physically embedded in the fluctuating environment of the plant cell. Their evolutionary heritage has shaped how the cell controls the genetic structure and the physical behavior of its organelle populations. While the specific genes involved in these processes are gradually being revealed, the governing principles underlying this controlled behavior remain poorly understood. As the genetic and physical dynamics of these organelles are central to bioenergetic performance and plant physiology, this challenges both fundamental biology and strategies to engineer better-performing plants. This article reviews current knowledge of the physical and genetic behavior of mitochondria and chloroplasts in plant cells. An overarching hypothesis is proposed whereby organelles face a tension between genetic robustness and individual control and responsiveness, and different species resolve this tension in different ways. As plants are immobile and thus subject to fluctuating environments, their organelles are proposed to favor individual responsiveness, sacrificing genetic robustness. Several notable features of plant organelles, including large genomes, mtDNA recombination, fragmented organelles, and plastid/mitochondrial differences may potentially be explained by this hypothesis. Finally, the ways that quantitative and systems biology can help shed light on the plethora of open questions in this field are highlighted.
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Affiliation(s)
- Iain G Johnston
- School of Biosciences, University of Birmingham, Birmingham, UK; Birmingham Institute for Forest Research, University of Birmingham, Birmingham, UK.
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10
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García-Gómez P, Almagro G, Sánchez-López ÁM, Bahaji A, Ameztoy K, Ricarte-Bermejo A, Baslam M, Antolín MC, Urdiain A, López-Belchi MD, López-Gómez P, Morán JF, Garrido J, Muñoz FJ, Baroja-Fernández E, Pozueta-Romero J. Volatile compounds other than CO 2 emitted by different microorganisms promote distinct posttranscriptionally regulated responses in plants. PLANT, CELL & ENVIRONMENT 2019; 42:1729-1746. [PMID: 30480826 DOI: 10.1111/pce.13490] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/16/2018] [Accepted: 11/20/2018] [Indexed: 05/23/2023]
Abstract
A "box-in-box" cocultivation system was used to investigate plant responses to microbial volatile compounds (VCs) and to evaluate the contributions of organic and inorganic VCs (VOCs and VICs, respectively) to these responses. Arabidopsis plants were exposed to VCs emitted by adjacent Alternaria alternata and Penicillium aurantiogriseum cultures, with and without charcoal filtration. No VOCs were detected in the headspace of growth chambers containing fungal cultures with charcoal filters. However, these growth chambers exhibited elevated CO2 and bioactive CO and NO headspace concentrations. Independently of charcoal filtration, VCs from both fungal phytopathogens promoted growth and distinct developmental changes. Plants cultured at CO2 levels observed in growth boxes containing fungal cultures were identical to those cultured at ambient CO2 . Plants exposed to charcoal-filtered fungal VCs, nonfiltered VCs, or superelevated CO2 levels exhibited transcriptional changes resembling those induced by increased irradiance. Thus, in the "box-in-box" system, (a) fungal VICs other than CO2 and/or VOCs not detected by our analytical systems strongly influence the plants' responses to fungal VCs, (b) different microorganisms release VCs with distinct action potentials, (c) transcriptional changes in VC-exposed plants are mainly due to enhanced photosynthesis signaling, and (d) regulation of some plant responses to fungal VCs is primarily posttranscriptional.
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Affiliation(s)
- Pablo García-Gómez
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | - Goizeder Almagro
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | | | - Abdellatif Bahaji
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | - Kinia Ameztoy
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | | | - Marouane Baslam
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
- Graduate School of Science and Technology and Department of Applied Biological Chemistry, Niigata University, Niigata, 950-2181, Japan
| | - María Carmen Antolín
- Facultades de Ciencias y Farmacia y Nutrición, Grupo de Fisiología del Estrés en Plantas (Departamento de Biología Ambiental), Unidad Asociada al CSIC (EEAD, Zaragoza, ICVV, Logroño), Universidad de Navarra, 31008, Pamplona, Spain
| | - Amadeo Urdiain
- Facultades de Ciencias y Farmacia y Nutrición, Grupo de Fisiología del Estrés en Plantas (Departamento de Biología Ambiental), Unidad Asociada al CSIC (EEAD, Zaragoza, ICVV, Logroño), Universidad de Navarra, 31008, Pamplona, Spain
| | - María Dolores López-Belchi
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
- Departamento de Producción Vegetal, Universidad de Concepción, Avenue Vicente Méndez 595, Chillán, Chile
| | - Pedro López-Gómez
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | - José Fernando Morán
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | - Julián Garrido
- Departamento de Ciencias, Universidad Pública de Navarra Campus Arrosadía, 31006, Pamplona, Spain
- Institute for Advanced Materials, Universidad Pública de Navarra Campus Arrosadía, 31006, Pamplona, Spain
| | - Francisco José Muñoz
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
| | | | - Javier Pozueta-Romero
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192, Mutiloabeti, Spain
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11
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McClain AM, Sharkey TD. Triose phosphate utilization and beyond: from photosynthesis to end product synthesis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1755-1766. [PMID: 30868155 PMCID: PMC6939825 DOI: 10.1093/jxb/erz058] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 03/07/2019] [Indexed: 05/18/2023]
Abstract
During photosynthesis, plants fix CO2 from the atmosphere onto ribulose-bisphosphate, producing 3-phosphoglycerate, which is reduced to triose phosphates (TPs). The TPs are then converted into the end products of photosynthesis. When a plant is photosynthesizing very quickly, it may not be possible to commit photosynthate to end products as fast as it is produced, causing a decrease in available phosphate and limiting the rate of photosynthesis to the rate of triose phosphate utilization (TPU). The occurrence of an observable TPU limitation is highly variable based on species and especially growth conditions, with TPU capacity seemingly regulated to be in slight excess of typical photosynthetic rates the plant might experience. The physiological effects of TPU limitation are discussed with an emphasis on interactions between the Calvin-Benson cycle and the light reactions. Methods for detecting TPU-limited data from gas exchange data are detailed and the impact on modeling of some physiological effects are shown. Special consideration is given to common misconceptions about TPU.
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Affiliation(s)
- Alan M McClain
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, East Lansing, MI, USA
- Plant Biotechnology for Health and Sustainability Program, East Lansing, MI, USA
| | - Thomas D Sharkey
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, East Lansing, MI, USA
- Plant Biotechnology for Health and Sustainability Program, East Lansing, MI, USA
- Plant Resilience Institute, Plant Biology Laboratories, East Lansing, MI, USA
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Revealing critical mechanisms of BR-mediated apple nursery tree growth using iTRAQ-based proteomic analysis. J Proteomics 2018; 173:139-154. [DOI: 10.1016/j.jprot.2017.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 11/19/2022]
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13
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Zhou M, Callaham JB, Reyes M, Stasiak M, Riva A, Zupanska AK, Dixon MA, Paul AL, Ferl RJ. Dissecting Low Atmospheric Pressure Stress: Transcriptome Responses to the Components of Hypobaria in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2017; 8:528. [PMID: 28443120 PMCID: PMC5385376 DOI: 10.3389/fpls.2017.00528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 03/24/2017] [Indexed: 05/10/2023]
Abstract
Controlled hypobaria presents biology with an environment that is never encountered in terrestrial ecology, yet the apparent components of hypobaria are stresses typical of terrestrial ecosystems. High altitude, for example, presents terrestrial hypobaria always with hypoxia as a component stress, since the relative partial pressure of O2 is constant in the atmosphere. Laboratory-controlled hypobaria, however, allows the dissection of pressure effects away from the effects typically associated with altitude, in particular hypoxia, as the partial pressure of O2 can be varied. In this study, whole transcriptomes of plants grown in ambient (97 kPa/pO2 = 21 kPa) atmospheric conditions were compared to those of plants transferred to five different atmospheres of varying pressure and oxygen composition for 24 h: 50 kPa/pO2 = 10 kPa, 25 kPa/pO2 = 5 kPa, 50 kPa/pO2 = 21 kPa, 25 kPa/pO2 = 21 kPa, or 97 kPa/pO2 = 5 kPa. The plants exposed to these environments were 10 day old Arabidopsis seedlings grown vertically on hydrated nutrient plates. In addition, 5 day old plants were also exposed for 24 h to the 50 kPa and ambient environments to evaluate age-dependent responses. The gene expression profiles from roots and shoots showed that the hypobaric response contained more complex gene regulation than simple hypoxia, and that adding back oxygen to normoxic conditions did not completely alleviate gene expression changes in hypobaric responses.
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Affiliation(s)
- Mingqi Zhou
- Department of Horticultural Sciences, Program in Plant Molecular and Cellular Biology, University of FloridaGainesville, FL, USA
| | - Jordan B. Callaham
- Department of Horticultural Sciences, Program in Plant Molecular and Cellular Biology, University of FloridaGainesville, FL, USA
| | | | - Michael Stasiak
- School of Environmental Sciences, University of GuelphGuelph, ON, Canada
| | - Alberto Riva
- Interdisciplinary Center for Biotechnology Research, University of FloridaGainesville, FL, USA
| | - Agata K. Zupanska
- Department of Horticultural Sciences, Program in Plant Molecular and Cellular Biology, University of FloridaGainesville, FL, USA
| | - Mike A. Dixon
- School of Environmental Sciences, University of GuelphGuelph, ON, Canada
| | - Anna-Lisa Paul
- Department of Horticultural Sciences, Program in Plant Molecular and Cellular Biology, University of FloridaGainesville, FL, USA
- *Correspondence: Anna-Lisa Paul
| | - Robert J. Ferl
- Department of Horticultural Sciences, Program in Plant Molecular and Cellular Biology, University of FloridaGainesville, FL, USA
- Interdisciplinary Center for Biotechnology Research, University of FloridaGainesville, FL, USA
- Robert J. Ferl
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14
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Mitochondrial structures during seed germination and early seedling development in Arabidopsis thaliana. Biologia (Bratisl) 2015. [DOI: 10.1515/biolog-2015-0130] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Jaipargas EA, Barton KA, Mathur N, Mathur J. Mitochondrial pleomorphy in plant cells is driven by contiguous ER dynamics. FRONTIERS IN PLANT SCIENCE 2015; 6:783. [PMID: 26442089 PMCID: PMC4585081 DOI: 10.3389/fpls.2015.00783] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
Mitochondria are pleomorphic, double membrane-bound organelles involved in cellular energetics in all eukaryotes. Mitochondria in animal and yeast cells are typically tubular-reticulate structures and several micro-meters long but in green plants they are predominantly observed as 0.2-1.5 μm punctae. While fission and fusion, through the coordinated activity of several conserved proteins, shapes mitochondria, the endoplasmic reticulum (ER) has recently been identified as an additional player in this process in yeast and mammalian cells. The mitochondria-ER relationship in plant cells remains largely uncharacterized. Here, through live-imaging of the entire range of mitochondria pleomorphy we uncover the underlying basis for the predominantly punctate mitochondrial form in plants. We demonstrate that mitochondrial morphology changes in response to light and cytosolic sugar levels in an ER mediated manner. Whereas, large ER polygons and low dynamics under dark conditions favor mitochondrial fusion and elongation, small ER polygons result in increased fission and predominantly small mitochondria. Hypoxia also reduces ER dynamics and increases mitochondrial fusion to produce giant mitochondria. By observing elongated mitochondria in normal plants and fission-impaired Arabidopsis nmt1-2 and drp3a mutants we also establish that thin extensions called matrixules and a beads-on-a-string mitochondrial phenotype are direct consequences of mitochondria-ER interactions.
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Affiliation(s)
| | | | | | - Jaideep Mathur
- *Correspondence: Jaideep Mathur, Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, ON N1G2W1, Canada
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16
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Schröder F, Lisso J, Obata T, Erban A, Maximova E, Giavalisco P, Kopka J, Fernie AR, Willmitzer L, Müssig C. Consequences of induced brassinosteroid deficiency in Arabidopsis leaves. BMC PLANT BIOLOGY 2014; 14:309. [PMID: 25403461 PMCID: PMC4240805 DOI: 10.1186/s12870-014-0309-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/27/2014] [Indexed: 05/21/2023]
Abstract
BACKGROUND The identification of brassinosteroid (BR) deficient and BR insensitive mutants provided conclusive evidence that BR is a potent growth-promoting phytohormone. Arabidopsis mutants are characterized by a compact rosette structure, decreased plant height and reduced root system, delayed development, and reduced fertility. Cell expansion, cell division, and multiple developmental processes depend on BR. The molecular and physiological basis of BR action is diverse. The BR signalling pathway controls the activity of transcription factors, and numerous BR responsive genes have been identified. The analysis of dwarf mutants, however, may to some extent reveal phenotypic changes that are an effect of the altered morphology and physiology. This restriction holds particularly true for the analysis of established organs such as rosette leaves. RESULTS In this study, the mode of BR action was analysed in established leaves by means of two approaches. First, an inhibitor of BR biosynthesis (brassinazole) was applied to 21-day-old wild-type plants. Secondly, BR complementation of BR deficient plants, namely CPD (constitutive photomorphogenic dwarf)-antisense and cbb1 (cabbage1) mutant plants was stopped after 21 days. BR action in established leaves is associated with stimulated cell expansion, an increase in leaf index, starch accumulation, enhanced CO2 release by the tricarboxylic acid cycle, and increased biomass production. Cell number and protein content were barely affected. CONCLUSION Previous analysis of BR promoted growth focused on genomic effects. However, the link between growth and changes in gene expression patterns barely provided clues to the physiological and metabolic basis of growth. Our study analysed comprehensive metabolic data sets of leaves with altered BR levels. The data suggest that BR promoted growth may depend on the increased provision and use of carbohydrates and energy. BR may stimulate both anabolic and catabolic pathways.
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Affiliation(s)
- Florian Schröder
- />University of Potsdam, c/o Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Janina Lisso
- />University of Potsdam, c/o Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Toshihiro Obata
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Alexander Erban
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Eugenia Maximova
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Patrick Giavalisco
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Joachim Kopka
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Alisdair R Fernie
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Lothar Willmitzer
- />Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Carsten Müssig
- />University of Potsdam, c/o Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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17
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Link BM, Busse JS, Stankovic B. Seed-to-seed-to-seed growth and development of Arabidopsis in microgravity. ASTROBIOLOGY 2014; 14:866-875. [PMID: 25317938 PMCID: PMC4201294 DOI: 10.1089/ast.2014.1184] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 09/04/2014] [Indexed: 05/29/2023]
Abstract
Arabidopsis thaliana was grown from seed to seed wholly in microgravity on the International Space Station. Arabidopsis plants were germinated, grown, and maintained inside a growth chamber prior to returning to Earth. Some of these seeds were used in a subsequent experiment to successfully produce a second (back-to-back) generation of microgravity-grown Arabidopsis. In general, plant growth and development in microgravity proceeded similarly to those of the ground controls, which were grown in an identical chamber. Morphologically, the most striking feature of space-grown Arabidopsis was that the secondary inflorescence branches and siliques formed nearly perpendicular angles to the inflorescence stems. The branches grew out perpendicularly to the main inflorescence stem, indicating that gravity was the key determinant of branch and silique angle and that light had either no role or a secondary role in Arabidopsis branch and silique orientation. Seed protein bodies were 55% smaller in space seed than in controls, but protein assays showed only a 9% reduction in seed protein content. Germination rates for space-produced seed were 92%, indicating that the seeds developed in microgravity were healthy and viable. Gravity is not necessary for seed-to-seed growth of plants, though it plays a direct role in plant form and may influence seed reserves.
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Affiliation(s)
- Bruce M. Link
- Syngenta Biotechnology, Inc., Research Triangle Park, North Carolina, USA. (Contributions for this work were made prior to affiliation with Syngenta.)
| | - James S. Busse
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin, USA
| | - Bratislav Stankovic
- University of Information Science and Technology “St. Paul the Apostle,” Ohrid, Macedonia
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18
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Santrůček J, Vráblová M, Simková M, Hronková M, Drtinová M, Květoň J, Vrábl D, Kubásek J, Macková J, Wiesnerová D, Neuwithová J, Schreiber L. Stomatal and pavement cell density linked to leaf internal CO2 concentration. ANNALS OF BOTANY 2014; 114:191-202. [PMID: 24825295 PMCID: PMC4217638 DOI: 10.1093/aob/mcu095] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/04/2014] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS Stomatal density (SD) generally decreases with rising atmospheric CO2 concentration, Ca. However, SD is also affected by light, air humidity and drought, all under systemic signalling from older leaves. This makes our understanding of how Ca controls SD incomplete. This study tested the hypotheses that SD is affected by the internal CO2 concentration of the leaf, Ci, rather than Ca, and that cotyledons, as the first plant assimilation organs, lack the systemic signal. METHODS Sunflower (Helianthus annuus), beech (Fagus sylvatica), arabidopsis (Arabidopsis thaliana) and garden cress (Lepidium sativum) were grown under contrasting environmental conditions that affected Ci while Ca was kept constant. The SD, pavement cell density (PCD) and stomatal index (SI) responses to Ci in cotyledons and the first leaves of garden cress were compared. (13)C abundance (δ(13)C) in leaf dry matter was used to estimate the effective Ci during leaf development. The SD was estimated from leaf imprints. KEY RESULTS SD correlated negatively with Ci in leaves of all four species and under three different treatments (irradiance, abscisic acid and osmotic stress). PCD in arabidopsis and garden cress responded similarly, so that SI was largely unaffected. However, SD and PCD of cotyledons were insensitive to Ci, indicating an essential role for systemic signalling. CONCLUSIONS It is proposed that Ci or a Ci-linked factor plays an important role in modulating SD and PCD during epidermis development and leaf expansion. The absence of a Ci-SD relationship in the cotyledons of garden cress indicates the key role of lower-insertion CO2 assimilation organs in signal perception and its long-distance transport.
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Affiliation(s)
- Jiří Santrůček
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic Biology Centre, Institute of Plant Molecular Biology AS CR, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Martina Vráblová
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Marie Simková
- Biology Centre, Institute of Plant Molecular Biology AS CR, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Marie Hronková
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic Biology Centre, Institute of Plant Molecular Biology AS CR, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Martina Drtinová
- Biology Centre, Institute of Plant Molecular Biology AS CR, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Jiří Květoň
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Daniel Vrábl
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Jiří Kubásek
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Jana Macková
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Dana Wiesnerová
- Biology Centre, Institute of Plant Molecular Biology AS CR, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Jitka Neuwithová
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Lukas Schreiber
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
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19
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Mondy S, Lenglet A, Cosson V, Pelletier S, Pateyron S, Gilard F, Scholte M, Brocard L, Couzigou JM, Tcherkez G, Péan M, Ratet P. GOLLUM [FeFe]-hydrogenase-like proteins are essential for plant development in normoxic conditions and modulate energy metabolism. PLANT, CELL & ENVIRONMENT 2014; 37:54-69. [PMID: 23639116 DOI: 10.1111/pce.12128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 05/23/2023]
Abstract
[FeFe]-hydrogenase-like genes encode [Fe4 S4]-containing proteins that are ubiquitous in eukaryotic cells. In humans, iron-only hydrogenase-like protein 1 (IOP1) represses hypoxia inducible factor-1α subunit (HIF1-α) at normal atmospheric partial O2 pressure (normoxia, 21 kPa O2). In yeasts, the nar1 mutant cannot grow at 21 kPa O2, but can develop at a lower O2 pressure (2 kPa O2). We show here that plant [FeFe]-hydrogenase-like GOLLUM genes are essential for plant development and cell cycle progression. The mutant phenotypes of these plants are seen in normoxic conditions, but not under conditions of mild hypoxia (5 kPa O2). Transcriptomic and metabolomic experiments showed that the mutation enhances the expression of some hypoxia-induced genes under normal atmospheric O2 conditions and changes the cellular content of metabolites related to energy metabolism. In conclusion, [FeFe]-hydrogenase-like proteins play a central role in eukaryotes including the adaptation of plants to the ambient O2 partial pressure.
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Affiliation(s)
- Samuel Mondy
- CNRS, Institut des Sciences du Végétal, Av. de la Terrasse, F-91198, Gif sur Yvette, France
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20
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Aoyama H, Kuroiwa T, Nakamura S. Chronological transition of mitochondrial morphology in Chlamydomonas reinhardtii (Chlorophyceae) poststationary phase growth(1). JOURNAL OF PHYCOLOGY 2013; 49:340-348. [PMID: 27008520 DOI: 10.1111/jpy.12040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 10/18/2012] [Indexed: 06/05/2023]
Abstract
In Chlamydomonas reinhardtii P. A. Dangeard, mitochondrial morphology has been observed during asexual cell division cycle, gamete and zygote formation, zygote maturation, and meiotic stages. However, the chronological transition of mitochondrial morphology after the stationary phase of vegetative growth, defined as the poststationary phase, remains unknown. Here, we examined the mitochondrial morphology in cells cultured for 4 months on agar plates to study mitochondrial dynamics in the poststationary phase. Fluorescence microscopy showed that the intricate thread-like structure of mitochondria gradually changed into a granular structure via fragmentation after the stationary phase in cultures of about 1 week of age. The number of mitochondrial nucleoids decreased from about 30 per cell at 1 week to about five per cell after 4 months of culture. The mitochondrial oxygen consumption decreased exponentially, but the mitochondria retained their membrane potential. The total quantity of mitochondrial DNA (mtDNA) of cells at 4 months decreased to 20% of that at 1 week. However, the mitochondrial genomic DNA length was unchanged, as intermediate lengths were not detected. In cells in which the total mtDNA amount was reduced artificially to 16% after treatment with 5-fluoro-2-deoxyuridine (FdUrd) for 1 week, the mitochondria remained as thread-like structures. The oxygen consumption rate of these cells corresponded to that of untreated cells at 1 week of culture. This suggests that a decrease in mtDNA does not directly induce the fragmentation of mitochondria. The results suggest that during the late poststationary phase, mitochondria converge to a minimum unit of a granular structure with a mitochondrial nucleoid.
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Affiliation(s)
- Hiroaki Aoyama
- Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan
- Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan
| | - Tsuneyoshi Kuroiwa
- Initiative Research Unit, College of Science, Rikkyo University, Nishi-Ikebukuro, Tokyo, 171-8501, Japan
| | - Soichi Nakamura
- Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan
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21
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Lee SC, Mustroph A, Sasidharan R, Vashisht D, Pedersen O, Oosumi T, Voesenek LACJ, Bailey-Serres J. Molecular characterization of the submergence response of the Arabidopsis thaliana ecotype Columbia. THE NEW PHYTOLOGIST 2011; 190:457-71. [PMID: 21231933 DOI: 10.1111/j.1469-8137.2010.03590.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
• A detailed description of the molecular response of Arabidopsis thaliana to submergence can aid the identification of genes that are critical to flooding survival. • Rosette-stage plants were fully submerged in complete darkness and shoot and root tissue was harvested separately after the O(2) partial pressure of the petiole and root had stabilized at c. 6 and 0.1 kPa, respectively. As controls, plants were untreated or exposed to darkness. Following quantitative profiling of cellular mRNAs with the Affymetrix ATH1 platform, changes in the transcriptome in response to submergence, early darkness, and O(2)-deprivation were evaluated by fuzzy k-means clustering. This identified genes co-regulated at the conditional, developmental or organ-specific level. Mutants for 10 differentially expressed HYPOXIA-RESPONSIVE UNKNOWN PROTEIN (HUP) genes were screened for altered submergence tolerance. • The analysis identified 34 genes that were ubiquitously co-regulated by submergence and O(2) deprivation. The biological functions of these include signaling, transcription, and anaerobic energy metabolism. HUPs comprised 40% of the co-regulated transcripts and mutants of seven of these genes were significantly altered in submergence tolerance. • The results define transcriptomic adjustments in response to submergence in the dark and demonstrate that the manipulation of HUPs can alter submergence tolerance.
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Affiliation(s)
- Seung Cho Lee
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
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22
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Hectors K, Jacques E, Prinsen E, Guisez Y, Verbelen JP, Jansen MAK, Vissenberg K. UV radiation reduces epidermal cell expansion in leaves of Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:4339-49. [PMID: 20702567 DOI: 10.1093/jxb/erq235] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Plants have evolved a broad spectrum of mechanisms to ensure survival under changing and suboptimal environmental conditions. Alterations of plant architecture are commonly observed following exposure to abiotic stressors. The mechanisms behind these environmentally controlled morphogenic traits are, however, poorly understood. In this report, the effects of a low dose of chronic ultraviolet (UV) radiation on leaf development are detailed. Arabidopsis rosette leaves exposed for 7, 12, or 19 d to supplemental UV radiation expanded less compared with non-UV controls. The UV-mediated decrease in leaf expansion is associated with a decrease in adaxial pavement cell expansion. Elevated UV does not affect the number and shape of adaxial pavement cells, nor the stomatal index. Cell expansion in young Arabidopsis leaves is asynchronous along a top-to-base gradient whereas, later in development, cells localized at both the proximal and distal half expand synchronously. The prominent, UV-mediated inhibition of cell expansion in young leaves comprises effects on the early asynchronous growing stage. Subsequent cell expansion during the synchronous phase cannot nullify the UV impact established during the asynchronous phase. The developmental stage of the leaf at the onset of UV treatment determines whether UV alters cell expansion during the synchronous and/or asynchronous stage. The effect of UV radiation on adaxial epidermal cell size appears permanent, whereas leaf shape is transiently altered with a reduced length/width ratio in young leaves. The data show that UV-altered morphogenesis is a temporal- and spatial-dependent process, implying that common single time point or single leaf zone analyses are inadequate.
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Affiliation(s)
- Kathleen Hectors
- Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
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23
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Ezquer I, Li J, Ovecka M, Baroja-Fernández E, Muñoz FJ, Montero M, Díaz de Cerio J, Hidalgo M, Sesma MT, Bahaji A, Etxeberria E, Pozueta-Romero J. Microbial volatile emissions promote accumulation of exceptionally high levels of starch in leaves in mono- and dicotyledonous plants. PLANT & CELL PHYSIOLOGY 2010; 51:1674-93. [PMID: 20739303 DOI: 10.1093/pcp/pcq126] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Microbes emit volatile compounds that affect plant growth and development. However, little or nothing is known about how microbial emissions may affect primary carbohydrate metabolism in plants. In this work we explored the effect on leaf starch metabolism of volatiles released from different microbial species ranging from Gram-negative and Gram-positive bacteria to fungi. Surprisingly, we found that all microbial species tested (including plant pathogens and species not normally interacting with plants) emitted volatiles that strongly promoted starch accumulation in leaves of both mono- and dicotyledonous plants. Starch content in leaves of plants treated for 2 d with microbial volatiles was comparable with or even higher than that of reserve organs such as potato tubers. Transcriptome and enzyme activity analyses of potato leaves exposed to volatiles emitted by Alternaria alternata revealed that starch overaccumulation was accompanied by up-regulation of sucrose synthase, invertase inhibitors, starch synthase class III and IV, starch branching enzyme and glucose-6-phosphate transporter. This phenomenon, designated as MIVOISAP (microbial volatiles-induced starch accumulation process), was also accompanied by down-regulation of acid invertase, plastidial thioredoxins, starch breakdown enzymes, proteins involved in internal amino acid provision and less well defined mechanisms involving a bacterial- type stringent response. Treatment of potato leaves with fungal volatiles also resulted in enhanced levels of sucrose, ADPglucose, UDPglucose and 3-phosphoglycerate. MIVOISAP is independent of the presence of sucrose in the culture medium and is strongly repressed by cysteine supplementation. The discovery that microbial volatiles trigger starch accumulation enhancement in leaves constitutes an unreported mechanism for the elicidation of plant carbohydrate metabolism by microbes.
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Affiliation(s)
- Ignacio Ezquer
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), Mutiloako etorbidea z/g, 31192 Mutiloabeti, Nafarroa, Spain
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Microhomology-mediated and nonhomologous repair of a double-strand break in the chloroplast genome of Arabidopsis. Proc Natl Acad Sci U S A 2010; 107:13954-9. [PMID: 20643920 DOI: 10.1073/pnas.1004326107] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Chloroplast DNA (cpDNA) is under great photooxidative stress, yet its evolution is very conservative compared with nuclear or mitochondrial genomes. It can be expected that DNA repair mechanisms play important roles in cpDNA survival and evolution, but they are poorly understood. To gain insight into how the most severe form of DNA damage, a double-strand break (DSB), is repaired, we have developed an inducible system in Arabidopsis that employs a psbA intron endonuclease from Chlamydomonas, I-CreII, that is targeted to the chloroplast using the rbcS1 transit peptide. In Chlamydomonas, an I-CreII-induced DSB in psbA was repaired, in the absence of the intron, by homologous recombination between repeated sequences (20-60 bp) abundant in that genome; Arabidopsis cpDNA is very repeat poor, however. Phenotypically strong and weak transgenic lines were examined and shown to correlate with I-CreII expression levels. Southern blot hybridizations indicated a substantial loss of DNA at the psbA locus, but not cpDNA as a whole, in the strongly expressing line. PCR analysis identified deletions nested around the I-CreII cleavage site indicative of DSB repair using microhomology (6-12 bp perfect repeats, or 10-16 bp with mismatches) and no homology. These results provide evidence of alternative DSB repair pathways in the Arabidopsis chloroplast that resemble the nuclear, microhomology-mediated and nonhomologous end joining pathways, in terms of the homology requirement. Moreover, when taken together with the results from Chlamydomonas, the data suggest an evolutionary relationship may exist between the repeat structure of the genome and the organelle's ability to repair broken chromosomes.
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Fraser LH, Greenall A, Carlyle C, Turkington R, Friedman CR. Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature. ANNALS OF BOTANY 2009; 103:769-75. [PMID: 19088084 PMCID: PMC2707864 DOI: 10.1093/aob/mcn252] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 09/29/2008] [Accepted: 11/10/2008] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS Changes in rainfall and temperature brought about through climate change may affect plant species distribution and community composition of grasslands. The primary objective of this study was to test how manipulation of water and temperature would influence the plasticity of stomatal density and leaf area of bluebunch wheatgrass, Pseudoroegneria spicata. It was hypothesized that: (1) an increased water supply will increase biomass and leaf area and decrease stomatal density, while a reduced water supply will cause the opposite effect; (2) an increase in temperature will reduce biomass and leaf area and increase stomatal density; and (3) the combinations of water and temperature treatments can be aligned along a stress gradient and that stomatal density will be highest at high stress. Methods The three water supply treatments were (1) ambient, (2) increased approx. 30% more than ambient through weekly watering and (3) decreased approx. 30 % less than ambient by rain shades. The two temperature treatments were (1) ambient and (2) increased approx. 1-3 degrees C by using open-top chambers. At the end of the second experimental growing season, above-ground biomass was harvested, oven-dried and weighed, tillers from bluebunch wheatgrass plants sampled, and the abaxial stomatal density and leaf area of tillers were measured. KEY RESULTS The first hypothesis was partially supported--reducing water supply increased stomatal density, but increasing water supply reduced leaf area. The second hypothesis was rejected. Finally, the third hypothesis could not be fully supported--rather than a linear response there appears to be a parabolic stomatal density response to stress. CONCLUSIONS Overall, the abaxial stomatal density and leaf area of bluebunch wheatgrass were plastic in their response to water and temperature manipulations. Although bluebunch wheatgrass has the potential to adapt to changing climate, the grass is limited in its ability to respond to a combination of reduced water and increased temperature.
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Affiliation(s)
- Lauchlan H Fraser
- Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, BC, Canada.
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Bajguz A, Hayat S. Effects of brassinosteroids on the plant responses to environmental stresses. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:1-8. [PMID: 19010688 DOI: 10.1016/j.plaphy.2008.10.002] [Citation(s) in RCA: 333] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 10/01/2008] [Indexed: 05/18/2023]
Abstract
Brassinosteroids are found in a wide range of organisms from lower to higher plants. They are steroidal plant hormones implicated in the promotion of plant growth and development. Brassinosteroid metabolism has long been known to be altered in plants responding to abiotic stresses and to undergo profound changes in plants interacting with bacterial, fungal and viral pathogens. This review describes the role of brassinosteroids in response to various kinds of stresses via activation of different mechanisms.
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Affiliation(s)
- Andrzej Bajguz
- Department of Plant Biochemistry, University of Bialystok, Swierkowa 20B, 15-950 Bialystok, Poland.
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Sekiya N, Yano K. Stomatal density of cowpea correlates with carbon isotope discrimination in different phosphorus, water and CO 2environments. NEW PHYTOLOGIST 2008; 179:799-807. [PMID: 18540975 DOI: 10.1111/j.1469-8137.2008.02518.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Nobuhito Sekiya
- Laboratory of Crop Science, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464‐8601, Japan
| | - Katsuya Yano
- Laboratory of Crop Science, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464‐8601, Japan
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Mullineaux PM, Lawson T. Measuring redox changes in vivo in leaves: prospects and technical challenges. Methods Mol Biol 2008; 476:67-77. [PMID: 19157009 DOI: 10.1007/978-1-59745-129-1_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In leaves, the functioning of many key proteins under conditions promoting oxidative stress depends to a large extent on the redox potential of the glutathione couple. Routine measurements of the glutathione pool in leaves are destructive and labor-intensive processes that tend to underestimate the redox state. Therefore, a challenge for plant scientists is to develop a tool capable of measuring the redox state of the glutathione couple spatially (at different levels of resolution) and temporally in tissues and subcellular compartments in vivo. This chapter highlights the possibilities of using redox-sensitive green fluorescence proteins (roGFPs) as real-time redox reporters for use in intact plants and focuses on practical assessments of using such bioindicators in different leaf cell types subjected to environmental change. The advantages and shortcomings of different GFP variants are discussed along with the choice of system for leaves and possible approaches to overcoming some of the problems. We consider roGFP1-12 as an ideal candidate for developing a redox reporter system in whole plants because it has several advantages over the other variants, with dual excitation peaks allowing a ratiometric approach, insensitivity to pH and halide ions, increased response times for real-time measurements, and appropriate emission wavelengths for use in leaves. We conclude that when using roGFP1-12 with specific cell promotors, it would be possible to target distinct cell compartments and tissues and monitor changes in glutathione redox state to determine the effects of reactive oxygen species on specific cellular components.
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Affiliation(s)
- Philip M Mullineaux
- Department of Biological Sciences, University of Essex, Colchester, Essex, UK
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KANG YY, GUO SR, LI J, DUAN JJ. Effects of 24-Epibrassinolide on Antioxidant System in Cucumber Seedling Roots Under Hypoxia Stress. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1671-2927(07)60046-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Teng N, Wang J, Chen T, Wu X, Wang Y, Lin J. Elevated CO2 induces physiological, biochemical and structural changes in leaves of Arabidopsis thaliana. THE NEW PHYTOLOGIST 2006; 172:92-103. [PMID: 16945092 DOI: 10.1111/j.1469-8137.2006.01818.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Leaves of Arabidopsis thaliana grown under elevated or ambient CO2 (700 or 370 micromol mol(-1), respectively) were examined for physiological, biochemical and structural changes. Stomatal characters, carbohydrate and mineral nutrient concentrations, leaf ultrastructure and plant hormone content were investigated using atomic absorption spectrophotometry, transmission electron microscopy and enzyme-linked immunosorbent assay (ELISA). Elevated CO2 reduced the stomatal density and stomatal index of leaves, and also reduced stomatal conductance and transpiration rate. Elevated CO2 increased chloroplast number, width and profile area, and starch grain size and number, but reduced the number of grana thylakoid membranes. Under elevated CO2, the concentrations of carbohydrates and plant hormones, with the exception of abscisic acid, increased whereas mineral nutrient concentrations declined. These results suggest that the changes in chloroplast ultrastructure may primarily be a consequence of increased starch accumulation. Accelerated A. thaliana growth and development in elevated CO2 could in part be attributed to increased foliar concentrations of plant hormones. The reductions in mineral nutrient concentrations may be a result of dilution by increased concentrations of carbohydrates and also of decreases in stomatal conductance and transpiration rate.
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Affiliation(s)
- Nianjun Teng
- Key laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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31
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Feng X, Arimura SI, Hirano HY, Sakamoto W, Tsutsumi N. Isolation of mutants with aberrant mitochondrial morphology from Arabidopsis thaliana. Genes Genet Syst 2005; 79:301-5. [PMID: 15599060 DOI: 10.1266/ggs.79.301] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To identify genes related to plant mitochondrial morphology and dynamics, novel mutants with respect to mitochondrial morphology were isolated from an ethyl methane sulphonate (EMS)-mutated population of Arabidopsis thaliana. Mitochondria were visualized by transforming Arabidopsis with a gene for a fusion protein consisting of GFP and a mitochondria-targeting pre-sequence. From 19,000 M2 populations, 17 mutants were isolated by fluorescent microscopic observations. All mitochondria in these mutants were longer and/or larger than wild-type mitochondria. The approximate chromosomal loci of the mutations of seven mutants that grew well were determined. The mitochondrial phenotypes of six of the mutants were recessive but the mitochondrial phenotype of the seventh mutant was dominant. Chromosomal rough mapping of the seven mutants showed that the mutations occurred at four different loci. At least one of these loci was novel, i.e., it was different from loci of other known mitochondrial morphology mutants of Arabidopsis and different from loci of Arabidopsis homologues of yeast genes related to mitochondrial morphology.
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Affiliation(s)
- Xiaoge Feng
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Kuang A, Popova A, McClure G, Musgrave ME. Dynamics of storage reserve deposition during Brassica rapa L. pollen and seed development in microgravity. INTERNATIONAL JOURNAL OF PLANT SCIENCES 2005; 166:85-96. [PMID: 15747444 DOI: 10.1086/425664] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Pollen and seeds share a developmental sequence characterized by intense metabolic activity during reserve deposition before drying to a cryptobiotic form. Neither pollen nor seed development has been well studied in the absence of gravity, despite the importance of these structures in supporting future long-duration manned habitation away from Earth. Using immature seeds (3-15 d postpollination) of Brassica rapa L. cv. Astroplants produced on the STS-87 flight of the space shuttle Columbia, we compared the progress of storage reserve deposition in cotyledon cells during early stages of seed development. Brassica pollen development was studied in flowers produced on plants grown entirely in microgravity on the Mir space station and fixed while on orbit. Cytochemical localization of storage reserves showed differences in starch accumulation between spaceflight and ground control plants in interior layers of the developing seed coat as early as 9 d after pollination. At this age, the embryo is in the cotyledon elongation stage, and there are numerous starch grains in the cotyledon cells in both flight and ground control seeds. In the spaceflight seeds, starch was retained after this stage, while starch grains decreased in size in the ground control seeds. Large and well-developed protein bodies were observed in cotyledon cells of ground control seeds at 15 d postpollination, but their development was delayed in the seeds produced during spaceflight. Like the developing cotyledonary tissues, cells of the anther wall and filaments from the spaceflight plants contained numerous large starch grains, while these were rarely seen in the ground controls. The tapetum remained swollen and persisted to a later developmental stage in the spaceflight plants than in the ground controls, even though most pollen grains appeared normal. These developmental markers indicate that Brassica seeds and pollen produced in microgravity were physiologically younger than those produced in 1 g. We hypothesize that microgravity limits mixing of the gaseous microenvironments inside the closed tissues and that the resulting gas composition surrounding the seeds and pollen retards their development.
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Affiliation(s)
- A Kuang
- Department of Biology, University of Texas-Pan American, Edinburg, Texas 78539, USA
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Paul AL, Schuerger AC, Popp MP, Richards JT, Manak MS, Ferl RJ. Hypobaric biology: Arabidopsis gene expression at low atmospheric pressure. PLANT PHYSIOLOGY 2004; 134:215-23. [PMID: 14701916 PMCID: PMC316301 DOI: 10.1104/pp.103.032607] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Revised: 09/22/2003] [Accepted: 10/07/2003] [Indexed: 05/20/2023]
Abstract
As a step in developing an understanding of plant adaptation to low atmospheric pressures, we have identified genes central to the initial response of Arabidopsis to hypobaria. Exposure of plants to an atmosphere of 10 kPa compared with the sea-level pressure of 101 kPa resulted in the significant differential expression of more than 200 genes between the two treatments. Less than one-half of the genes induced by hypobaria are similarly affected by hypoxia, suggesting that response to hypobaria is unique and is more complex than an adaptation to the reduced partial pressure of oxygen inherent to hypobaric environments. In addition, the suites of genes induced by hypobaria confirm that water movement is a paramount issue at low atmospheric pressures, because many of gene products intersect abscisic acid-related, drought-induced pathways. A motivational constituent of these experiments is the need to address the National Aeronautics and Space Administration's plans to include plants as integral components of advanced life support systems. The design of bioregenerative life support systems seeks to maximize productivity within structures engineered to minimize mass and resource consumption. Currently, there are severe limitations to producing Earth-orbital, lunar, or Martian plant growth facilities that contain Earth-normal atmospheric pressures within light, transparent structures. However, some engineering limitations can be offset by growing plants in reduced atmospheric pressures. Characterization of the hypobaric response can therefore provide data to guide systems engineering development for bioregenerative life support, as well as lead to fundamental insights into aspects of desiccation metabolism and the means by which plants monitor water relations.
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Affiliation(s)
- Anna-Lisa Paul
- Program in Plant Molecular and Cellular Biology, Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611, USA
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Ramonell KM, McClure G, Musgrave ME. Oxygen control of ethylene biosynthesis during seed development in Arabidopsis thaliana (L.) Heynh. PLANT, CELL & ENVIRONMENT 2002; 25:793-801. [PMID: 12092614 DOI: 10.1046/j.1365-3040.2002.00864.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An unforeseen side-effect on plant growth in reduced oxygen is the loss of seed production at concentrations around 25% atmospheric (50 mmol mol-1 O2). In this study, the model plant Arabidopsis thaliana (L.) Heynh. cv. 'Columbia' was used to investigate the effect of low oxygen on ethylene biosynthesis during seed development. Plants were grown in a range of oxygen concentrations (210 [equal to ambient], 160, 100, 50 and 25 mmol mol-1) with 0.35 mmol mol-1 CO2 in N2. Ethylene in full-sized siliques was sampled using gas chromatography, and viable seed production was determined at maturity. Molecular analysis of ethylene biosynthesis was accomplished using cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase in ribonuclease protection assays and in situ hybridizations. No ethylene was detected in siliques from plants grown at 50 and 25 mmol mol-1 O2. At the same time, silique ACC oxidase mRNA increased three-fold comparing plants grown under the lowest oxygen with ambient controls, whereas ACC synthase mRNA was unaffected. As O2 decreased, tissue-specific patterning of ACC oxidase and ACC synthase gene expression shifted from the embryo to the silique wall. These data demonstrate how low O2 modulates the activity and expression of the ethylene biosynthetic pathway during seed development in Arabidopsis.
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Affiliation(s)
- K M Ramonell
- Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
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