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Chen H, Li S, Li L, Hu H, Zhao J. Arabidopsis EMB1990 Encoding a Plastid-Targeted YlmG Protein Is Required for Chloroplast Biogenesis and Embryo Development. FRONTIERS IN PLANT SCIENCE 2018; 9:181. [PMID: 29503657 PMCID: PMC5820536 DOI: 10.3389/fpls.2018.00181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 01/31/2018] [Indexed: 05/24/2023]
Abstract
In higher plants, embryo development originated from fertilized egg cell is the first step of the life cycle. The chloroplast participates in many essential metabolic pathways, and its function is highly associated with embryo development. However, the mechanisms and relevant genetic components by which the chloroplast functions in embryogenesis are largely uncharacterized. In this paper, we describe the Arabidopsis EMB1990 gene, encoding a plastid-targeted YlmG protein which is required for chloroplast biogenesis and embryo development. Loss of the EMB1990/YLMG1-1 resulted in albino seeds containing abortive embryos, and the morphological development of homozygous emb1990 embryos was disrupted after the globular stage. Our results showed that EMB1990/YLMG1-1 was expressed in the primordia and adaxial region of cotyledon during embryogenesis, and the encoded protein was targeted to the chloroplast. TEM observation of cellular ultrastructure showed that chloroplast biogenesis was impaired in emb1990 embryo cells. Expression of certain plastid genes was also affected in the loss-of-function mutants, including genes encoding core protein complex subunits located in the thylakoid membrane. Moreover, the tissue-specific genes of embryo development were misexpressed in emb1990 mutant, including genes known to delineate cell fate decisions in the SAM (shoot apical meristem), cotyledon and hypophysis. Taken together, we propose that the nuclear-encoded YLMG1-1 is targeted to the chloroplast and required for normal plastid gene expression. Hence, YLMG1-1 plays a critical role in Arabidopsis embryogenesis through participating in chloroplast biogenesis.
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302
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Świda-Barteczka A, Krieger-Liszkay A, Bilger W, Voigt U, Hensel G, Szweykowska-Kulinska Z, Krupinska K. The plastid-nucleus located DNA/RNA binding protein WHIRLY1 regulates microRNA-levels during stress in barley (Hordeum vulgare L.). RNA Biol 2018. [PMID: 29947287 DOI: 10.1101/197202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
In this article a novel mechanism of retrograde signaling by chloroplasts during stress is described. This mechanism involves the DNA/RNA binding protein WHIRLY1 as a regulator of microRNA levels. By virtue of its dual localization in chloroplasts and the nucleus of the same cell, WHIRLY1 was proposed as an excellent candidate coordinator of chloroplast function and nuclear gene expression. Comparison of wild-type and transgenic plants with an RNAi-mediated knockdown of WHIRLY1 showed, that the transgenic plants were unable to cope with continuous high light conditions. They were impaired in production of several microRNAs mediating post-transcriptional responses during stress. The results support a central role of WHIRLY1 in retrograde signaling and also underpin a so far underestimated role of microRNAs in this process.
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Affiliation(s)
- Aleksandra Świda-Barteczka
- a Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology , Adam Mickiewicz University , Poznań , Poland
| | - Anja Krieger-Liszkay
- b Institute for Integrative Biology of the Cell, Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique , Université Paris-Sud, Université Paris-Saclay , Gif-sur-Yvette , France
| | - Wolfgang Bilger
- c Institute of Botany , Christian-Albrechts-University , Kiel , Germany
| | - Ulrike Voigt
- c Institute of Botany , Christian-Albrechts-University , Kiel , Germany
| | - Götz Hensel
- d Department of Physiology and Cell Biology , Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) , Seeland OT Gatersleben , Germany
| | - Zofia Szweykowska-Kulinska
- a Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology , Adam Mickiewicz University , Poznań , Poland
| | - Karin Krupinska
- c Institute of Botany , Christian-Albrechts-University , Kiel , Germany
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303
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Phua SY, Pornsiriwong W, Chan KX, Estavillo GM, Pogson BJ. Development of strategies for genetic manipulation and fine-tuning of a chloroplast retrograde signal 3'-phosphoadenosine 5'-phosphate. PLANT DIRECT 2018; 2:e00031. [PMID: 31245680 PMCID: PMC6508504 DOI: 10.1002/pld3.31] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/09/2017] [Accepted: 12/07/2017] [Indexed: 05/22/2023]
Abstract
Homeostasis of metabolism and regulation of stress-signaling pathways are important for plant growth. The metabolite 3'-phosphoadenosine-5'-phosphate (PAP) plays dual roles as a chloroplast retrograde signal during drought and high light stress, as well as a toxic by-product of secondary sulfur metabolism, and thus, its levels are regulated by the chloroplastic phosphatase, SAL1. Constitutive PAP accumulation in sal1 mutants improves drought tolerance but can impair growth and alter rosette morphology. Therefore, it is of interest to derive strategies to enable controlled and targeted PAP manipulation that could enhance drought tolerance while minimizing the negative effects on plant growth. We systematically tested the potential and efficiency of multiple established transgenic manipulation tools in altering PAP levels in Arabidopsis. Dexamethasone (dex)-inducible silencing of SAL1 via hpRNAi [pOpOff:SAL1hpRNAi] yielded reduction in SAL1 transcript and protein levels, yet failed to significantly induce PAP accumulation. Surprisingly, this was not due to insufficient silencing of the inducible system, as constitutive silencing using a strong promoter to drive hpRNAi and amiRNA targeting the SAL1 transcript also failed to increase PAP content or induce a sal1-like plant morphology despite significantly reducing the SAL1 transcript levels. In contrast, using dex-inducible expression of SAL1 cDNA to complement an Arabidopsis sal1 mutant successfully modulated PAP levels and restored rosette growth in a dosage-dependent manner. Results from this inducible complementation system indicate that plants with intermediate PAP levels could have improved rosette growth without compromising its drought tolerance. Additionally, preliminary evidence suggests that SAL1 cDNA driven by promoters of genes expressed specifically during early developmental stages such as ABA-Insensitive 3 (ABI3) could be another potential strategy for studying and optimizing PAP levels and drought tolerance while alleviating the negative impact of PAP on plant growth in sal1. Thus, we have identified ways that can allow future dissection into multiple aspects of stress and developmental regulation mediated by this chloroplast signal.
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Affiliation(s)
- Su Yin Phua
- ARC Centre of Excellence in Plant Energy BiologyResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
| | - Wannarat Pornsiriwong
- ARC Centre of Excellence in Plant Energy BiologyResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
- Department of BiochemistryFaculty of ScienceKasetsart UniversityBangkokThailand
| | - Kai Xun Chan
- ARC Centre of Excellence in Plant Energy BiologyResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
| | - Gonzalo M. Estavillo
- ARC Centre of Excellence in Plant Energy BiologyResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
- CSIRO Agriculture & Food, Black MountainCanberraACTAustralia
| | - Barry J. Pogson
- ARC Centre of Excellence in Plant Energy BiologyResearch School of BiologyThe Australian National UniversityCanberraACTAustralia
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304
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Abstract
Since its first use in plants in 2007, high-throughput RNA sequencing (RNA-Seq) has generated a vast amount of data for both model and nonmodel species. Organellar transcriptomes, however, are virtually always overlooked at the data analysis step. We therefore developed ChloroSeq, a bioinformatic pipeline aimed at facilitating the systematic analysis of chloroplast RNA metabolism, and we provide here a step-by-step user's manual. Following the alignment of quality-controlled data to the genome of interest, ChloroSeq measures genome expression level along with splicing and RNA editing efficiencies. When used in combination with the Tuxedo suite (TopHat and Cufflinks), ChloroSeq allows the simultaneous analysis of organellar and nuclear transcriptomes, opening the way to a better understanding of nucleus-organelle cross talk. We also describe the use of R commands to produce publication-quality figures based on ChloroSeq outputs. The effectiveness of the pipeline is illustrated through analysis of an RNA-Seq dataset covering the transition from growth to maturation to senescence of Arabidopsis thaliana leaves.
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305
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Chloroplast signaling and quality control. Essays Biochem 2017; 62:13-20. [DOI: 10.1042/ebc20170048] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/06/2017] [Accepted: 10/13/2017] [Indexed: 11/17/2022]
Abstract
Although chloroplasts contain their own genetic system and are semi-autonomous cell organelles, plastid biogenesis and homeostasis are heavily dependent on the nucleo-cytosolic compartment. These two cellular compartments are closely co-ordinated through a complex signaling network comprising both anterograde and retrograde signaling chains. Developmental changes or any perturbation in the chloroplast system induced by a particular stress resulting from changes in environmental conditions such as excess light, elevated temperature, nutrient limitation, pathogen infection, give rise to specific signals. They migrate out of the chloroplast and are perceived by the nucleus where they elicit changes in expression of particular genes that allow for the maintenance of plastid homeostasis toward environmental cues. These genes mainly include those of photosynthesis-associated proteins, chaperones, proteases, nucleases and immune/defense proteins. Besides this transcriptional response, a chloroplast quality control system exists that is involved in the repair and turnover of damaged plastid proteins. This system degrades aggregated or damaged proteins and it can even remove entire chloroplasts when they have suffered heavy damage. This response comprises several processes such as plastid autophagy and ubiquitin–proteasome mediated proteolysis that occurs on the plastid envelope through the action of the ubiquitin–proteasome system.
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306
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Wang P, Hendron RW, Kelly S. Transcriptional control of photosynthetic capacity: conservation and divergence from Arabidopsis to rice. THE NEW PHYTOLOGIST 2017; 216:32-45. [PMID: 28727145 DOI: 10.1111/nph.14682] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 05/16/2017] [Indexed: 05/12/2023]
Abstract
Contents 32 I. 32 II. 33 III. 36 IV. 41 43 References 43 SUMMARY: Photosynthesis is one of the most important biological processes on Earth. It provides the consumable energy upon which almost all organisms are dependent, and modulates the composition of the planet's atmosphere. To carry out photosynthesis, plants require a large cohort of genes. These genes encode proteins that capture light energy, store energy in sugars and build the subcellular structures required to facilitate this energy capture. Although the function of many of these genes is known, little is understood about the transcriptional networks that coordinate their expression. This review places our understanding of the transcriptional regulation of photosynthesis in Arabidopsis thaliana in an evolutionary context, to provide new insight into transcriptional regulatory networks that control photosynthesis gene expression in grasses. The similarities and differences between the rice and Arabidopsis networks are highlighted, revealing substantial disparity between the two systems. In addition, avenues are identified that may be exploited for photosynthesis engineering projects in the future.
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Affiliation(s)
- Peng Wang
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Ross-William Hendron
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
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307
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Ishiga Y, Watanabe M, Ishiga T, Tohge T, Matsuura T, Ikeda Y, Hoefgen R, Fernie AR, Mysore KS. The SAL-PAP Chloroplast Retrograde Pathway Contributes to Plant Immunity by Regulating Glucosinolate Pathway and Phytohormone Signaling. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:829-841. [PMID: 28703028 DOI: 10.1094/mpmi-03-17-0055-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chloroplasts have a crucial role in plant immunity against pathogens. Increasing evidence suggests that phytopathogens target chloroplast homeostasis as a pathogenicity mechanism. In order to regulate the performance of chloroplasts under stress conditions, chloroplasts produce retrograde signals to alter nuclear gene expression. Many signals for the chloroplast retrograde pathway have been identified, including chlorophyll intermediates, reactive oxygen species, and metabolic retrograde signals. Although there is a reasonably good understanding of chloroplast retrograde signaling in plant immunity, some signals are not well-understood. In order to understand the role of chloroplast retrograde signaling in plant immunity, we investigated Arabidopsis chloroplast retrograde signaling mutants in response to pathogen inoculation. sal1 mutants (fry1-2 and alx8) responsible for the SAL1-PAP retrograde signaling pathway showed enhanced disease symptoms not only to the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000 but, also, to the necrotrophic pathogen Pectobacterium carotovorum subsp. carotovorum EC1. Glucosinolate profiles demonstrated the reduced accumulation of aliphatic glucosinolates in the fry1-2 and alx8 mutants compared with the wild-type Col-0 in response to DC3000 infection. In addition, quantification of multiple phytohormones and analyses of their gene expression profiles revealed that both the salicylic acid (SA)- and jasmonic acid (JA)-mediated signaling pathways were down-regulated in the fry1-2 and alx8 mutants. These results suggest that the SAL1-PAP chloroplast retrograde pathway is involved in plant immunity by regulating the SA- and JA-mediated signaling pathways.
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Affiliation(s)
- Yasuhiro Ishiga
- 1 Noble Research Institute, LLC, Ardmore, OK 73401, U.S.A
- 2 Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Mutsumi Watanabe
- 3 Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany; and
| | - Takako Ishiga
- 1 Noble Research Institute, LLC, Ardmore, OK 73401, U.S.A
- 2 Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Takayuki Tohge
- 3 Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany; and
| | - Takakazu Matsuura
- 4 Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Yoko Ikeda
- 4 Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Rainer Hoefgen
- 3 Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany; and
| | - Alisdair R Fernie
- 3 Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany; and
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308
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A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments. Proc Natl Acad Sci U S A 2017; 114:E8110-E8117. [PMID: 28874535 DOI: 10.1073/pnas.1712206114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because-in nature-photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report that the chloroplast thylakoid lumenal protein MAINTENANCE OF PHOTOSYSTEM II UNDER HIGH LIGHT 2 (MPH2; encoded by At4g02530) is required for growth acclimation of Arabidopsis thaliana plants under controlled photoinhibitory light and fluctuating light environments. Evidence is presented that mph2 mutant light stress susceptibility results from a defect in photosystem II (PSII) repair, and our results are consistent with the hypothesis that MPH2 is involved in disassembling monomeric complexes during regeneration of dimeric functional PSII supercomplexes. Moreover, mph2-and previously characterized PSII repair-defective mutants-exhibited reduced growth under fluctuating light conditions, while PSII photoprotection-impaired mutants did not. These findings suggest that repair is not only required for PSII maintenance under static high-irradiance light conditions but is also a regulatory mechanism facilitating photosynthetic adaptation under fluctuating light environments. This work has implications for improvement of agricultural plant productivity through engineering PSII repair.
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309
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Sánchez-Corrionero Á, Sánchez-Vicente I, González-Pérez S, Corrales A, Krieger-Liszkay A, Lorenzo Ó, Arellano JB. Singlet oxygen triggers chloroplast rupture and cell death in the zeaxanthin epoxidase defective mutant aba1 of Arabidopsis thaliana under high light stress. JOURNAL OF PLANT PHYSIOLOGY 2017; 216:188-196. [PMID: 28709027 DOI: 10.1016/j.jplph.2017.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 06/09/2017] [Accepted: 06/12/2017] [Indexed: 06/07/2023]
Abstract
The two Arabidopsis thaliana mutants, aba1 and max4, were previously identified as sharing a number of co-regulated genes with both the flu mutant and Arabidopsis cell suspension cultures exposed to high light (HL). On this basis, we investigated whether aba1 and max4 were generating high amounts of singlet oxygen (1O2) and activating 1O2-mediated cell death. Thylakoids of aba1 produced twice as much 1O2 as thylakoids of max4 and wild type (WT) plants when illuminated with strong red light. 1O2 was measured using the spin probe 2,2,6,6-tetramethyl-4-piperidone hydrochloride. 77-K chlorophyll fluorescence emission spectra of thylakoids revealed lower aggregation of the light harvesting complex II in aba1. This was rationalized as a loss of connectivity between photosystem II (PSII) units and as the main cause for the high yield of 1O2 generation in aba1. Up-regulation of the 1O2 responsive gene AAA-ATPase was only observed with statistical significant in aba1 under HL. Two early jasmonate (JA)-responsive genes, JAZ1 and JAZ5, encoding for two repressor proteins involved in the negative feedback regulation of JA signalling, were not up-regulated to the WT plant levels. Chloroplast aggregation followed by chloroplast rupture and eventual cell death was observed by confocal imaging of the fluorescence emission of leaf cells of transgenic aba1 plants expressing the chimeric fusion protein SSU-GFP. Cell death was not associated with direct 1O2 cytotoxicity in aba1, but rather with a delayed stress response. In contrast, max4 did not show evidence of 1O2-mediated cell death. In conclusion, aba1 may serve as an alternative model to other 1O2-overproducing mutants of Arabidopsis for investigating 1O2-mediated cell death.
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Affiliation(s)
- Álvaro Sánchez-Corrionero
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Cordel de merinas 52, Salamanca 37008, Spain; Departamento de Botánica y Fisiología Vegetal, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/Río Duero 12, Salamanca 37185, Spain; Department of Biotechnology, Center for Plant Genomics and Biotechnology, Universidad Politécnica de Madrid, Pozuelo de Alarcón 28223, Spain
| | - Inmaculada Sánchez-Vicente
- Departamento de Botánica y Fisiología Vegetal, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/Río Duero 12, Salamanca 37185, Spain
| | - Sergio González-Pérez
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Cordel de merinas 52, Salamanca 37008, Spain
| | - Ascensión Corrales
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Cordel de merinas 52, Salamanca 37008, Spain; Departamento de Botánica y Fisiología Vegetal, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/Río Duero 12, Salamanca 37185, Spain
| | - Anja Krieger-Liszkay
- Institute for Integrative Biology of the Cell, Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Institut des sciences du vivant Frédéric Joliot, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex 91198, France
| | - Óscar Lorenzo
- Departamento de Botánica y Fisiología Vegetal, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/Río Duero 12, Salamanca 37185, Spain
| | - Juan B Arellano
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Cordel de merinas 52, Salamanca 37008, Spain.
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310
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Llamas E, Pulido P, Rodriguez-Concepcion M. Interference with plastome gene expression and Clp protease activity in Arabidopsis triggers a chloroplast unfolded protein response to restore protein homeostasis. PLoS Genet 2017; 13:e1007022. [PMID: 28937985 PMCID: PMC5627961 DOI: 10.1371/journal.pgen.1007022] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 10/04/2017] [Accepted: 09/15/2017] [Indexed: 11/27/2022] Open
Abstract
Disruption of protein homeostasis in chloroplasts impairs the correct functioning of essential metabolic pathways, including the methylerythritol 4-phosphate (MEP) pathway for the production of plastidial isoprenoids involved in photosynthesis and growth. We previously found that misfolded and aggregated forms of the first enzyme of the MEP pathway are degraded by the Clp protease with the involvement of Hsp70 and Hsp100/ClpC1 chaperones in Arabidopsis thaliana. By contrast, the combined unfolding and disaggregating actions of Hsp70 and Hsp100/ClpB3 chaperones allow solubilization and hence reactivation of the enzyme. The repair pathway is promoted when the levels of ClpB3 proteins increase upon reduction of Clp protease activity in mutants or wild-type plants treated with the chloroplast protein synthesis inhibitor lincomycin (LIN). Here we show that LIN treatment rapidly increases the levels of aggregated proteins in the chloroplast, unleashing a specific retrograde signaling pathway that up-regulates expression of ClpB3 and other nuclear genes encoding plastidial chaperones. As a consequence, folding capacity is increased to restore protein homeostasis. This sort of chloroplast unfolded protein response (cpUPR) mechanism appears to be mediated by the heat shock transcription factor HsfA2. Expression of HsfA2 and cpUPR-related target genes is independent of GUN1, a central integrator of retrograde signaling pathways. However, double mutants defective in both GUN1 and plastome gene expression (or Clp protease activity) are seedling lethal, confirming that the GUN1 protein is essential for protein homeostasis in chloroplasts.
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Affiliation(s)
- Ernesto Llamas
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, Barcelona, Spain
| | - Pablo Pulido
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, Barcelona, Spain
| | - Manuel Rodriguez-Concepcion
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, Barcelona, Spain
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311
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Börner T. The discovery of plastid-to-nucleus retrograde signaling-a personal perspective. PROTOPLASMA 2017; 254:1845-1855. [PMID: 28337540 PMCID: PMC5610210 DOI: 10.1007/s00709-017-1104-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/10/2017] [Indexed: 05/21/2023]
Abstract
DNA and machinery for gene expression have been discovered in chloroplasts during the 1960s. It was soon evident that the chloroplast genome is relatively small, that most genes for chloroplast-localized proteins reside in the nucleus and that chloroplast membranes, ribosomes, and protein complexes are composed of proteins encoded in both the chloroplast and the nuclear genome. This situation has made the existence of mechanisms highly probable that coordinate the gene expression in plastids and nucleus. In the 1970s, the first evidence for plastid signals controlling nuclear gene expression was provided by studies on plastid ribosome deficient mutants with reduced amounts and/or activities of nuclear-encoded chloroplast proteins including the small subunit of Rubisco, ferredoxin NADP+ reductase, and enzymes of the Calvin cycle. This review describes first models of plastid-to-nucleus signaling and their discovery. Today, many plastid signals are known. They do not only balance gene expression in chloroplasts and nucleus during developmental processes but are also generated in response to environmental changes sensed by the organelles.
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Affiliation(s)
- Thomas Börner
- Institute of Biology, Molecular Genetics, Humboldt University Berlin, Rhoda Erdmann Haus, Philippstr 13, 10115, Berlin, Germany.
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312
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Yang M, Jiang JP, Xie X, Chu YD, Fan Y, Cao XP, Xue S, Chi ZY. Chloroplasts Isolation from Chlamydomonas reinhardtii under Nitrogen Stress. FRONTIERS IN PLANT SCIENCE 2017; 8:1503. [PMID: 28900438 PMCID: PMC5581827 DOI: 10.3389/fpls.2017.01503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
Triacylglycerols are produced in abundance through chloroplast and endoplasmic reticulum pathways in some microalgae exposed to stress, though the relative contribution of either pathway remains elusive. Characterization of these pathways requires isolation of the organelles. In this study, an efficient and reproducible approach, including homogenous batch cultures of nitrogen-deprived algal cells in photobioreactors, gentle cell disruption using a simple custom-made disruptor with mechanical shear force, optimized differential centrifugation and Percoll density gradient centrifugation, was developed to isolate chloroplasts from Chlamydomonas reinhardtii subjected to nitrogen stress. Using this approach, the maximum limited stress duration was 4 h and the stressed cells exhibited 19 and 32% decreases in intracellular chlorophyll and nitrogen content, respectively. Chloroplasts with 48 - 300 μg chlorophyll were successfully isolated from stressed cells containing 10 mg chlorophyll. These stressed chloroplasts appeared intact, as monitored by ultrastructure observation and a novel quality control method involving the fatty acid biomarkers. This approach can provide sufficient quantities of intact stressed chloroplasts for subcellular biochemical studies in microalgae.
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Affiliation(s)
- Miao Yang
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
- University of Chinese Academy of SciencesBeijing, China
- School of Life Sciences and Biotechnology, Dalian University of TechnologyDalian, China
| | - Jun-Peng Jiang
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
- University of Chinese Academy of SciencesBeijing, China
| | - Xi Xie
- Liaoning Ocean and Fisheries Science Research InstituteDalian, China
| | - Ya-Dong Chu
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Yan Fan
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
- University of Chinese Academy of SciencesBeijing, China
| | - Xu-Peng Cao
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Song Xue
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Zhan-You Chi
- School of Life Sciences and Biotechnology, Dalian University of TechnologyDalian, China
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313
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Lu S, Li C, Zhang Y, Zheng Z, Liu D. Functional Disruption of a Chloroplast Pseudouridine Synthase Desensitizes Arabidopsis Plants to Phosphate Starvation. FRONTIERS IN PLANT SCIENCE 2017; 8:1421. [PMID: 28861101 PMCID: PMC5559850 DOI: 10.3389/fpls.2017.01421] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 07/31/2017] [Indexed: 05/29/2023]
Abstract
Phosphate (Pi) deficiency is a common nutritional stress of plants in both agricultural and natural ecosystems. Plants respond to Pi starvation in the environment by triggering a suite of biochemical, physiological, and developmental changes that increase survival and growth. The key factors that determine plant sensitivity to Pi starvation, however, are unclear. In this research, we identified an Arabidopsis mutant, dps1, with greatly reduced sensitivity to Pi starvation. The dps1 phenotypes are caused by a mutation in the previously characterized SVR1 (SUPPRESSION OF VARIAGATION 1) gene, which encodes a chloroplast-localized pseudouridine synthase. The mutation of SVR1 results in defects in chloroplast rRNA biogenesis, which subsequently reduces chloroplast translation. Another mutant, rps5, which contains a mutation in the chloroplast ribosomal protein RPS5 and has reduced chloroplast translation, also displayed decreased sensitivity to Pi starvation. Furthermore, wild type plants treated with lincomycin, a chemical inhibitor of chloroplast translation, showed similar growth phenotypes and Pi starvation responses as dps1 and rps5. These results suggest that impaired chloroplast translation desensitizes plants to Pi starvation. Combined with previously published results showing that enhanced leaf photosynthesis augments plant responses to Pi starvation, we propose that the decrease in responses to Pi starvation in dps1, rps5, and lincomycin-treated plants is due to their reduced demand for Pi input from the environment.
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Affiliation(s)
| | | | | | | | - Dong Liu
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua UniversityBeijing, China
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314
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Liu Y, Zhang W, Zhang K, You Q, Yan H, Jiao Y, Jiang J, Xu W, Su Z. Genome-wide mapping of DNase I hypersensitive sites reveals chromatin accessibility changes in Arabidopsis euchromatin and heterochromatin regions under extended darkness. Sci Rep 2017. [PMID: 28642500 PMCID: PMC5481438 DOI: 10.1038/s41598-017-04524-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Light, as the energy source in photosynthesis, is essential for plant growth and development. Extended darkness causes dramatic gene expression changes. In this study, we applied DNase-seq (DNase I hypersensitive site sequencing) to study changes of chromatin accessibility in euchromatic and heterochromatic regions under extended darkness in Arabidopsis. We generated 27 Gb DNase-seq and 67.6 Gb RNA-seq data to investigate chromatin accessibility changes and global gene expression under extended darkness and control condition in Arabidopsis. We found that ~40% DHSs (DNaseI hypersensitive sites) were diminished under darkness. In non-TE regions, the majority of DHS-changed genes were DHS-diminished under darkness. A total of 519 down-regulated genes were associated with diminished DHSs under darkness, mainly involved in photosynthesis process and retrograde signaling, and were regulated by chloroplast maintenance master regulators such as GLK1. In TE regions, approximately half of the DHS-changed TEs were DHS-increased under darkness and were primarily associated with the LTR/Gypsy retrotransposons in the heterochromatin flanking the centromeres. In contrast, DHS-diminished TEs under darkness were enriched in Copia, LINE, and MuDR dispersed across chromosomes. Together, our results indicated that extended darkness resulted in more increased chromatin compaction in euchromatin and decompaction in heterochromatin, thus further leading to gene expression changes in Arabidopsis.
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Affiliation(s)
- Yue Liu
- College of Biological Sciences, China Agricultural University, State key Laboratory of Plant Physiology and Biochemistry, Beijing, China
| | - Wenli Zhang
- Nanjing Agricultural University, State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, Nanjing, China
| | - Kang Zhang
- College of Biological Sciences, China Agricultural University, State key Laboratory of Plant Physiology and Biochemistry, Beijing, China
| | - Qi You
- College of Biological Sciences, China Agricultural University, State key Laboratory of Plant Physiology and Biochemistry, Beijing, China
| | - Hengyu Yan
- College of Biological Sciences, China Agricultural University, State key Laboratory of Plant Physiology and Biochemistry, Beijing, China
| | - Yuannian Jiao
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, China
| | - Jiming Jiang
- University of Wisconsin-Madison, Department of Horticulture, Madison, WI, USA
| | - Wenying Xu
- College of Biological Sciences, China Agricultural University, State key Laboratory of Plant Physiology and Biochemistry, Beijing, China
| | - Zhen Su
- College of Biological Sciences, China Agricultural University, State key Laboratory of Plant Physiology and Biochemistry, Beijing, China.
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315
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Bose J, Munns R, Shabala S, Gilliham M, Pogson B, Tyerman SD. Chloroplast function and ion regulation in plants growing on saline soils: lessons from halophytes. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3129-3143. [PMID: 28472512 DOI: 10.1093/jxb/erx142] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Salt stress impacts multiple aspects of plant metabolism and physiology. For instance it inhibits photosynthesis through stomatal limitation, causes excessive accumulation of sodium and chloride in chloroplasts, and disturbs chloroplast potassium homeostasis. Most research on salt stress has focused primarily on cytosolic ion homeostasis with few studies of how salt stress affects chloroplast ion homeostasis. This review asks the question whether membrane-transport processes and ionic relations are differentially regulated between glycophyte and halophyte chloroplasts and whether this contributes to the superior salt tolerance of halophytes. The available literature indicates that halophytes can overcome stomatal limitation by switching to CO2 concentrating mechanisms and increasing the number of chloroplasts per cell under saline conditions. Furthermore, salt entry into the chloroplast stroma may be critical for grana formation and photosystem II activity in halophytes but not in glycophytes. Salt also inhibits some stromal enzymes (e.g. fructose-1,6-bisphosphatase) to a lesser extent in halophyte species. Halophytes accumulate more chloride in chloroplasts than glycophytes and appear to use sodium in functional roles. We propose the molecular identities of candidate transporters that move sodium, chloride and potassium across chloroplast membranes and discuss how their operation may regulate photochemistry and photosystem I and II activity in chloroplasts.
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Affiliation(s)
- Jayakumar Bose
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
| | - Rana Munns
- Australian Research Council Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Sergey Shabala
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
| | - Barry Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Stephen D Tyerman
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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316
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Ganusova EE, Rice JH, Carlew TS, Patel A, Perrodin-Njoku E, Hewezi T, Burch-Smith TM. Altered Expression of a Chloroplast Protein Affects the Outcome of Virus and Nematode Infection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:478-488. [PMID: 28323529 DOI: 10.1094/mpmi-02-17-0031-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The chloroplast-resident RNA helicase ISE2 (INCREASED SIZE EXCLUSION LIMIT2) can modulate the formation and distribution of plasmodesmata and intercellular trafficking. We have determined that ISE2 expression is induced by viral infection. Therefore, the responses of Nicotiana benthamiana plants with varying levels of ISE2 expression to infection by Tobacco mosaic virus and Turnip mosaic virus were examined. Surprisingly, increased or decreased ISE2 expression led to faster viral systemic spread and, in some cases, enhanced systemic necrosis. The contributions of RNA silencing and hormone-mediated immune responses to the increased viral susceptibility of these plants were assessed. In addition, Arabidopsis thaliana plants with increased ISE2 expression were found to be more susceptible to infection by the beet cyst nematode Heterodera schachtii. Our analyses provide intriguing insights into unexpected functional roles of a chloroplast protein in mediating plant-pathogen interactions. The possible roles of plasmodesmata in determining the outcomes of these interactions are also discussed.
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Affiliation(s)
- Elena E Ganusova
- 1 Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, U.S.A
| | - J Hollis Rice
- 2 Department of Plant Sciences, University of Tennessee; and
| | - Timothy S Carlew
- 1 Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, U.S.A
| | - Akshita Patel
- 1 Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, U.S.A
| | - Emmanuel Perrodin-Njoku
- 3 National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, NY 14623, U.S.A
| | - Tarek Hewezi
- 2 Department of Plant Sciences, University of Tennessee; and
| | - Tessa M Burch-Smith
- 1 Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, U.S.A
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317
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Shi K, Gu J, Guo H, Zhao L, Xie Y, Xiong H, Li J, Zhao S, Song X, Liu L. Transcriptome and proteomic analyses reveal multiple differences associated with chloroplast development in the spaceflight-induced wheat albino mutant mta. PLoS One 2017; 12:e0177992. [PMID: 28542341 PMCID: PMC5443577 DOI: 10.1371/journal.pone.0177992] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/05/2017] [Indexed: 01/10/2023] Open
Abstract
Chloroplast development is an integral part of plant survival and growth, and occurs in parallel with chlorophyll biosynthesis. However, little is known about the mechanisms underlying chloroplast development in hexaploid wheat. Here, we obtained a spaceflight-induced wheat albino mutant mta. Chloroplast ultra-structural observation showed that chloroplasts of mta exhibit abnormal morphology and distribution compared to wild type. Photosynthetic pigments content was also significantly decreased in mta. Transcriptome and chloroplast proteome profiling of mta and wild type were done to identify differentially expressed genes (DEGs) and proteins (DEPs), respectively. In total 4,588 DEGs including 1,980 up- and 2,608 down-regulated, and 48 chloroplast DEPs including 15 up- and 33 down-regulated were identified in mta. Classification of DEGs revealed that most were involved in chloroplast development, chlorophyll biosynthesis, or photosynthesis. Besides, transcription factors such as PIF3, GLK and MYB which might participate in those pathways were also identified. The correlation analysis between DEGs and DEPs revealed that the transcript-to-protein in abundance was functioned into photosynthesis and chloroplast relevant groups. Real time qPCR analysis validated that the expression level of genes encoding photosynthetic proteins was significantly decreased in mta. Together, our results suggest that the molecular mechanism for albino leaf color formation in mta is a thoroughly regulated and complicated process. The combined analysis of transcriptome and proteome afford comprehensive information for further research on chloroplast development mechanism in wheat. And spaceflight provides a potential means for mutagenesis in crop breeding.
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Affiliation(s)
- Kui Shi
- School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiayu Gu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huijun Guo
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Linshu Zhao
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yongdun Xie
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hongchun Xiong
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junhui Li
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shirong Zhao
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiyun Song
- School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong, China
- * E-mail: (LL); (XS)
| | - Luxiang Liu
- School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (LL); (XS)
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318
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Convergence of mitochondrial and chloroplastic ANAC017/PAP-dependent retrograde signalling pathways and suppression of programmed cell death. Cell Death Differ 2017; 24:955-960. [PMID: 28498364 DOI: 10.1038/cdd.2017.68] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 03/04/2017] [Accepted: 04/03/2017] [Indexed: 12/23/2022] Open
Abstract
The energy-converting organelles mitochondria and chloroplasts are tightly embedded in cellular metabolism and stress response. To appropriately control organelle function, extensive regulatory mechanisms are at play that involve two-way exchange between the nucleus and mitochondria/chloroplasts. In recent years, our understanding of how mitochondria and chloroplasts provide 'retrograde' feedback to the nucleus, resulting in targeted transcriptional changes, has greatly increased. Nevertheless, mitochondrial and chloroplast retrograde signalling have largely been studied independently, and only few points of interaction have been found or proposed. Through reassessment of recent publications, this perspective proposes that two of the most well-studied retrograde signalling pathways in plants, those mediated by ANAC017 and those mediated by phosphoadenosine phosphate (PAP), are most likely convergent and can direct overlapping genes. Furthermore, at least part of this common retrograde response appears targeted towards suppression of programmed cell death (PCD) triggered by organellar defects. The identified target genes are discussed in light of their roles in PCD suppression and amplifying the signalling cascade via positive-feedback loops. Finally, a mechanism is proposed that may explain why the convergence of PAP/ANAC017-dependent signalling appears capable of suppressing some types of PCD lesions, but not others, based on the subcellular location of the initial PCD-inducing dysfunction.
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319
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Li Z, Yuan S, Jia H, Gao F, Zhou M, Yuan N, Wu P, Hu Q, Sun D, Luo H. Ectopic expression of a cyanobacterial flavodoxin in creeping bentgrass impacts plant development and confers broad abiotic stress tolerance. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:433-446. [PMID: 27638479 PMCID: PMC5362689 DOI: 10.1111/pbi.12638] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/10/2016] [Accepted: 09/13/2016] [Indexed: 05/18/2023]
Abstract
Flavodoxin (Fld) plays a pivotal role in photosynthetic microorganisms as an alternative electron carrier flavoprotein under adverse environmental conditions. Cyanobacterial Fld has been demonstrated to be able to substitute ferredoxin of higher plants in most electron transfer processes under stressful conditions. We have explored the potential of Fld for use in improving plant stress response in creeping bentgrass (Agrostis stolonifera L.). Overexpression of Fld altered plant growth and development. Most significantly, transgenic plants exhibited drastically enhanced performance under oxidative, drought and heat stress as well as nitrogen (N) starvation, which was associated with higher water retention and cell membrane integrity than wild-type controls, modified expression of heat-shock protein genes, production of more reduced thioredoxin, elevated N accumulation and total chlorophyll content as well as up-regulated expression of nitrite reductase and N transporter genes. Further analysis revealed that the expression of other stress-related genes was also impacted in Fld-expressing transgenics. Our data establish a key role of Fld in modulating plant growth and development and plant response to multiple sources of adverse environmental conditions in crop species. This demonstrates the feasibility of manipulating Fld in crop species for genetic engineering of plant stress tolerance.
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Affiliation(s)
- Zhigang Li
- College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanHubeiChina
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Shuangrong Yuan
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Haiyan Jia
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- The Applied Plant Genomics Laboratory of Crop Genomics and Bioinformatics Centreand National Key Laboratory of Crop Genetics and Germplasm EnhancementNanjing Agricultural UniversityNanjingJiangsuChina
| | - Fangyuan Gao
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- Crop Research InstituteSichuan Academy of Agricultural SciencesChengduSichuanChina
| | - Man Zhou
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Ning Yuan
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Peipei Wu
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Qian Hu
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Dongfa Sun
- College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanHubeiChina
| | - Hong Luo
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
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320
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ATHB17 enhances stress tolerance by coordinating photosynthesis associated nuclear gene and ATSIG5 expression in response to abiotic stress. Sci Rep 2017; 7:45492. [PMID: 28358040 PMCID: PMC5371990 DOI: 10.1038/srep45492] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 02/28/2017] [Indexed: 11/08/2022] Open
Abstract
Photosynthesis is sensitive to environmental stress and must be efficiently modulated in response to abiotic stress. However, the underlying mechanisms are not well understood. Here we report that ARABIDOPSIS THALIANA HOMEOBOX 17 (ATHB17), an Arabidopsis HD-Zip transcription factor, regulated the expression of a number of photosynthesis associated nuclear genes (PhANGs) involved in the light reaction and ATSIG5 in response to abiotic stress. ATHB17 was responsive to ABA and multiple stress treatments. ATHB17-overexpressing plants displayed enhanced stress tolerance, whereas its knockout mutant was more sensitive compared to the wild type. Through RNA-seq and quantitative real-time reverse transcription PCR (qRT-PCR) analysis, we found that ATHB17 did not affect the expression of many known stress-responsive marker genes. Interestingly, we found that ATHB17 down-regulated many PhANGs and could directly modulate the expression of several PhANGs by binding to their promoters. Moreover, we identified ATSIG5, encoding a plastid sigma factor, as one of the target genes of ATHB17. Loss of ATSIG5 reduced salt tolerance while overexpression of ATSIG5 enhanced salt tolerance, similar to that of ATHB17. ATHB17 can positively modulate the expression of many plastid encoded genes (PEGs) through regulation of ATSIG5. Taken together, our results suggest that ATHB17 may play an important role in protecting plants by adjusting expression of PhANGs and PEGs in response to abiotic stresses.
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321
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Pornsiriwong W, Estavillo GM, Chan KX, Tee EE, Ganguly D, Crisp PA, Phua SY, Zhao C, Qiu J, Park J, Yong MT, Nisar N, Yadav AK, Schwessinger B, Rathjen J, Cazzonelli CI, Wilson PB, Gilliham M, Chen ZH, Pogson BJ. A chloroplast retrograde signal, 3'-phosphoadenosine 5'-phosphate, acts as a secondary messenger in abscisic acid signaling in stomatal closure and germination. eLife 2017; 6. [PMID: 28323614 PMCID: PMC5406205 DOI: 10.7554/elife.23361] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/16/2017] [Indexed: 02/06/2023] Open
Abstract
Organelle-nuclear retrograde signaling regulates gene expression, but its roles in specialized cells and integration with hormonal signaling remain enigmatic. Here we show that the SAL1-PAP (3'-phosphoadenosine 5'- phosphate) retrograde pathway interacts with abscisic acid (ABA) signaling to regulate stomatal closure and seed germination in Arabidopsis. Genetically or exogenously manipulating PAP bypasses the canonical signaling components ABA Insensitive 1 (ABI1) and Open Stomata 1 (OST1); priming an alternative pathway that restores ABA-responsive gene expression, ROS bursts, ion channel function, stomatal closure and drought tolerance in ost1-2. PAP also inhibits wild type and abi1-1 seed germination by enhancing ABA sensitivity. PAP-XRN signaling interacts with ABA, ROS and Ca2+; up-regulating multiple ABA signaling components, including lowly-expressed Calcium Dependent Protein Kinases (CDPKs) capable of activating the anion channel SLAC1. Thus, PAP exhibits many secondary messenger attributes and exemplifies how retrograde signals can have broader roles in hormone signaling, allowing chloroplasts to fine-tune physiological responses.
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Affiliation(s)
- Wannarat Pornsiriwong
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia.,Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Gonzalo M Estavillo
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia.,CSIRO Agriculture and Food, Acton, Australia
| | - Kai Xun Chan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Estee E Tee
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Diep Ganguly
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Peter A Crisp
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Su Yin Phua
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Chenchen Zhao
- School of Science and Health, Western Sydney University, Richmond, Australia
| | - Jiaen Qiu
- ARC Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Australia.,Waite Research Institute, University of Adelaide, Glen Osmond, Australia
| | - Jiyoung Park
- Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, San Diego, United States
| | - Miing Tiem Yong
- School of Science and Health, Western Sydney University, Richmond, Australia
| | - Nazia Nisar
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Arun Kumar Yadav
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | | | - John Rathjen
- Research School of Biology, The Australian National University, Acton, Australia
| | - Christopher I Cazzonelli
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia.,Hawkesbury Institute for the Environment, Western Sydney University, Richmond, Australia
| | - Philippa B Wilson
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
| | - Matthew Gilliham
- ARC Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Australia
| | - Zhong-Hua Chen
- School of Science and Health, Western Sydney University, Richmond, Australia.,College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Barry J Pogson
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia
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322
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Geigenberger P, Thormählen I, Daloso DM, Fernie AR. The Unprecedented Versatility of the Plant Thioredoxin System. TRENDS IN PLANT SCIENCE 2017; 22:249-262. [PMID: 28139457 DOI: 10.1016/j.tplants.2016.12.008] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/25/2016] [Accepted: 12/14/2016] [Indexed: 05/18/2023]
Abstract
Thioredoxins are ubiquitous enzymes catalyzing reversible disulfide-bond formation to regulate structure and function of many proteins in diverse organisms. In recent years, reverse genetics and biochemical approaches were used to resolve the functions, specificities, and interactions of the different thioredoxin isoforms and reduction systems in planta and revealed the most versatile thioredoxin system of all organisms. Here we review the emerging roles of the thioredoxin system, namely the integration of thylakoid energy transduction, metabolism, gene expression, growth, and development under fluctuating environmental conditions. We argue that these new developments help us to understand why plants organize such a divergent composition of thiol redox networks and provide insights into the regulatory hierarchy that operates between them.
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Affiliation(s)
- Peter Geigenberger
- Ludwig-Maximilians-Universität (LMU) München, Department Biology I, 82152 Planegg-Martinsried, Germany.
| | - Ina Thormählen
- Ludwig-Maximilians-Universität (LMU) München, Department Biology I, 82152 Planegg-Martinsried, Germany
| | - Danilo M Daloso
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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323
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Shao MR, Kumar Kenchanmane Raju S, Laurie JD, Sanchez R, Mackenzie SA. Stress-responsive pathways and small RNA changes distinguish variable developmental phenotypes caused by MSH1 loss. BMC PLANT BIOLOGY 2017; 17:47. [PMID: 28219335 PMCID: PMC5319189 DOI: 10.1186/s12870-017-0996-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 02/08/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Proper regulation of nuclear-encoded, organelle-targeted genes is crucial for plastid and mitochondrial function. Among these genes, MutS Homolog 1 (MSH1) is notable for generating an assortment of mutant phenotypes with varying degrees of penetrance and pleiotropy. Stronger phenotypes have been connected to stress tolerance and epigenetic changes, and in Arabidopsis T-DNA mutants, two generations of homozygosity with the msh1 insertion are required before severe phenotypes begin to emerge. These observations prompted us to examine how msh1 mutants contrast according to generation and phenotype by profiling their respective transcriptomes and small RNA populations. RESULTS Using RNA-seq, we analyze pathways that are associated with MSH1 loss, including abiotic stresses such as cold response, pathogen defense and immune response, salicylic acid, MAPK signaling, and circadian rhythm. Subtle redox and environment-responsive changes also begin in the first generation, in the absence of strong phenotypes. Using small RNA-seq we further identify miRNA changes, and uncover siRNA trends that indicate modifications at the chromatin organization level. In all cases, the magnitude of changes among protein-coding genes, transposable elements, and small RNAs increases according to generation and phenotypic severity. CONCLUSION Loss of MSH1 is sufficient to cause large-scale regulatory changes in pathways that have been individually linked to one another, but rarely described all together within a single mutant background. This study enforces the recognition of organelles as critical integrators of both internal and external cues, and highlights the relationship between organelle and nuclear regulation in fundamental aspects of plant development and stress signaling. Our findings also encourage further investigation into potential connections between organelle state and genome regulation vis-á-vis small RNA feedback.
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Affiliation(s)
- Mon-Ray Shao
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE USA
| | | | - John D. Laurie
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE USA
- Sainsbury Laboratory, University of Cambridge, Cambridge, UK
| | - Robersy Sanchez
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE USA
| | - Sally A. Mackenzie
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE USA
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324
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Tamburino R, Vitale M, Ruggiero A, Sassi M, Sannino L, Arena S, Costa A, Batelli G, Zambrano N, Scaloni A, Grillo S, Scotti N. Chloroplast proteome response to drought stress and recovery in tomato (Solanum lycopersicum L.). BMC PLANT BIOLOGY 2017; 17:40. [PMID: 28183294 PMCID: PMC5301458 DOI: 10.1186/s12870-017-0971-0] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 01/04/2017] [Indexed: 05/18/2023]
Abstract
BACKGROUND Drought is a major constraint for plant growth and crop productivity that is receiving an increased attention due to global climate changes. Chloroplasts act as environmental sensors, however, only partial information is available on stress-induced mechanisms within plastids. Here, we investigated the chloroplast response to a severe drought treatment and a subsequent recovery cycle in tomato through physiological, metabolite and proteomic analyses. RESULTS Under stress conditions, tomato plants showed stunted growth, and elevated levels of proline, abscisic acid (ABA) and late embryogenesis abundant gene transcript. Proteomics revealed that water deficit deeply affects chloroplast protein repertoire (31 differentially represented components), mainly involving energy-related functional species. Following the rewatering cycle, physiological parameters and metabolite levels indicated a recovery of tomato plant functions, while proteomics revealed a still ongoing adjustment of the chloroplast protein repertoire, which was even wider than during the drought phase (54 components differentially represented). Changes in gene expression of candidate genes and accumulation of ABA suggested the activation under stress of a specific chloroplast-to-nucleus (retrograde) signaling pathway and interconnection with the ABA-dependent network. CONCLUSIONS Our results give an original overview on the role of chloroplast as enviromental sensor by both coordinating the expression of nuclear-encoded plastid-localised proteins and mediating plant stress response. Although our data suggest the activation of a specific retrograde signaling pathway and interconnection with ABA signaling network in tomato, the involvement and fine regulation of such pathway need to be further investigated through the development and characterization of ad hoc designed plant mutants.
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Affiliation(s)
- Rachele Tamburino
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy
| | - Monica Vitale
- Institute for the Animal Production System in the Mediterranean Environment, National Research Council of Italy (CNR-ISPAAM), via Argine 1085, 80147, Napoli, Italy
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Pansini, 80100, Napoli, Italy
| | - Alessandra Ruggiero
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy
| | - Mauro Sassi
- Institute for the Animal Production System in the Mediterranean Environment, National Research Council of Italy (CNR-ISPAAM), via Argine 1085, 80147, Napoli, Italy
| | - Lorenza Sannino
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy
| | - Simona Arena
- Institute for the Animal Production System in the Mediterranean Environment, National Research Council of Italy (CNR-ISPAAM), via Argine 1085, 80147, Napoli, Italy
| | - Antonello Costa
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy
| | - Giorgia Batelli
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy
| | - Nicola Zambrano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Pansini, 80100, Napoli, Italy
- Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate S.c. a R.l, via Pansini, 80100, Napoli, Italy
| | - Andrea Scaloni
- Institute for the Animal Production System in the Mediterranean Environment, National Research Council of Italy (CNR-ISPAAM), via Argine 1085, 80147, Napoli, Italy
| | - Stefania Grillo
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy
| | - Nunzia Scotti
- Institute of Biosciences and BioResources, National Research Council of Italy (CNR-IBBR), via Università 133, 80055, Portici, NA, Italy.
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325
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Kucharewicz W, Distelfeld A, Bilger W, Müller M, Munné-Bosch S, Hensel G, Krupinska K. Acceleration of leaf senescence is slowed down in transgenic barley plants deficient in the DNA/RNA-binding protein WHIRLY1. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:983-996. [PMID: 28338757 PMCID: PMC5441857 DOI: 10.1093/jxb/erw501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
WHIRLY1 in barley was isolated as a potential regulator of the senescence-associated gene HvS40. In order to investigate whether the plastid-nucleus-located DNA/RNA-binding protein WHIRLY1 plays a role in regulation of leaf senescence, primary foliage leaves from transgenic barley plants with an RNAi-mediated knockdown of the WHIRLY1 gene were characterized by typical senescence parameters, namely pigment contents, function and composition of the photosynthetic apparatus, as well as expression of selected genes known to be either down- or up-regulated during leaf senescence. When the plants were grown at low light intensity, senescence progression was similar between wild-type and RNAi-W1 plants. Likewise, dark-induced senescence of detached leaves was not affected by reduction of WHIRLY1. When plants were grown at high light intensity, however, senescence was induced prematurely in wild-type plants but was delayed in RNAi-W1 plants. This result suggests that WHIRLY1 plays a role in light sensing and/or stress communication between chloroplasts and the nucleus.
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Affiliation(s)
| | - Assaf Distelfeld
- Department of Molecular Biology and Ecology of Plants, University of Tel Aviv, Tel Aviv, Israel
| | - Wolfgang Bilger
- Institute of Botany, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Maren Müller
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain
| | - Sergi Munné-Bosch
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain
| | - Götz Hensel
- Plant Reproductive Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Seeland/OT Gatersleben, Germany
| | - Karin Krupinska
- Institute of Botany, Christian-Albrechts-University of Kiel, Kiel, Germany
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326
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Page MT, McCormac AC, Smith AG, Terry MJ. Singlet oxygen initiates a plastid signal controlling photosynthetic gene expression. THE NEW PHYTOLOGIST 2017; 213:1168-1180. [PMID: 27735068 PMCID: PMC5244666 DOI: 10.1111/nph.14223] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/19/2016] [Indexed: 05/20/2023]
Abstract
Retrograde signals from the plastid regulate photosynthesis-associated nuclear genes and are essential to successful chloroplast biogenesis. One model is that a positive haem-related signal promotes photosynthetic gene expression in a pathway that is abolished by the herbicide norflurazon. Far-red light (FR) pretreatment and transfer to white light also results in plastid damage and loss of photosynthetic gene expression. Here, we investigated whether norflurazon and FR pretreatment affect the same retrograde signal. We used transcriptome analysis and real-time reverse transcription-polymerase chain reaction (RT-PCR) to analyse the effects of these treatments on nuclear gene expression in various Arabidopsis (Arabidopsis thaliana) retrograde signalling mutants. Results showed that the two treatments inhibited largely different nuclear gene sets, suggesting that they affected different retrograde signals. Moreover, FR pretreatment resulted in singlet oxygen (1 O2 ) production and a rapid inhibition of photosynthetic gene expression. This inhibition was partially blocked in the executer1executer2 mutant, which is impaired in 1 O2 signalling. Our data support a new model in which a 1 O2 retrograde signal, generated by chlorophyll precursors, inhibits expression of key photosynthetic and chlorophyll synthesis genes to prevent photo-oxidative damage during de-etiolation. Such a signal would provide a counterbalance to the positive haem-related signal to fine tune regulation of chloroplast biogenesis.
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Affiliation(s)
- Mike T. Page
- Biological SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
| | - Alex C. McCormac
- Biological SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
| | - Alison G. Smith
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Matthew J. Terry
- Biological SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
- Institute for Life SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
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327
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Li RQ, Jiang M, Liu YH, Zheng YC, Huang JZ, Wu JM, Shu QY. The xantha Marker Trait Is Associated with Altered Tetrapyrrole Biosynthesis and Deregulated Transcription of PhANGs in Rice. FRONTIERS IN PLANT SCIENCE 2017; 8:901. [PMID: 28620402 PMCID: PMC5449477 DOI: 10.3389/fpls.2017.00901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/15/2017] [Indexed: 05/08/2023]
Abstract
The xantha marker trait, which is controlled by a down-regulating epi-mutation of OsGUN4, has been applied to the production of hybrid rice. However, the molecular basis for the ability of xantha mutants to attain high photosynthetic capacity even with decreased chlorophyll contents has not been characterized. In the present study, we observed that the total chlorophyll content of the xantha mutant was only 27.2% of that of the wild-type (WT) plants. However, the xantha mutant still accumulated 59.9% of the WT δ-aminolevulinic acid content, 72.8% of the WT Mg-protoporphyrin IX content, and 63.0% of the WT protochlorophyllide a content. Additionally, the protoporphyrin IX and heme contents in the mutant increased to 155.0 and 160.0%, respectively, of the WT levels. A search for homologs resulted in the identification of 124 rice genes involved in tetrapyrrole biosynthesis and photosynthesis. With the exception of OsGUN4, OsHO-1, and OsHO-2, the expression levels of the genes involved in tetrapyrrole biosynthesis were significantly higher in the xantha mutant than in the WT plants, as were all 72 photosynthesis-associated nuclear genes. In contrast, there were no differences between the xantha mutant and WT plants regarding the expression of all 22 photosynthesis-associated chloroplast genes. Furthermore, the abundance of 1O2 and the expression levels of 1O2-related genes were lower in the xantha mutant than in the WT plants, indicating 1O2-mediated retrograde signaling was repressed in the mutant plants. These results suggested that the abundance of protoporphyrin IX used for chlorophyll synthesis decreased in the mutant, which ultimately decreased the amount of chlorophyll in the xantha mutant. Additionally, the up-regulated expression of photosynthesis-associated nuclear genes enabled the mutant to attain a high photosynthetic capacity. Our findings confirm that OsGUN4 plays an important role in tetrapyrrole biosynthesis and photosynthesis in rice. GUN4, chlorophyll synthesis pathways, and photosynthetic activities are highly conserved in plants and hence, novel traits (e.g., xantha marker trait) may be generated in other cereal crops by modifying the GUN4 gene.
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Affiliation(s)
- Rui-Qing Li
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang UniversityHangzhou, China
- Hubei Collaborative Innovation Center for Grain IndustryJingzhou, China
- Department of Chemistry, Zhejiang UniversityHangzhou, China
| | - Meng Jiang
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang UniversityHangzhou, China
| | - Yan-Hua Liu
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang UniversityHangzhou, China
| | - Yun-Chao Zheng
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang UniversityHangzhou, China
- Institute of Nuclear Agricultural Sciences, Zhejiang UniversityHangzhou, China
| | - Jian-Zhong Huang
- Institute of Nuclear Agricultural Sciences, Zhejiang UniversityHangzhou, China
| | - Jian-Min Wu
- Department of Chemistry, Zhejiang UniversityHangzhou, China
| | - Qing-Yao Shu
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang UniversityHangzhou, China
- Hubei Collaborative Innovation Center for Grain IndustryJingzhou, China
- *Correspondence: Qing-Yao Shu,
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328
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Hirosawa Y, Ito-Inaba Y, Inaba T. Ubiquitin-Proteasome-Dependent Regulation of Bidirectional Communication between Plastids and the Nucleus. FRONTIERS IN PLANT SCIENCE 2017; 8:310. [PMID: 28360917 PMCID: PMC5350108 DOI: 10.3389/fpls.2017.00310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/20/2017] [Indexed: 05/08/2023]
Abstract
Plastids are DNA-containing organelles and can have unique differentiation states depending on age, tissue, and environment. Plastid biogenesis is optimized by bidirectional communication between plastids and the nucleus. Import of nuclear-encoded proteins into plastids serves as anterograde signals and vice versa, plastids themselves send retrograde signals to the nucleus, thereby controlling de novo synthesis of nuclear-encoded plastid proteins. Recently, it has become increasingly evident that the ubiquitin-proteasome system regulates both the import of anterograde plastid proteins and retrograde signaling from plastids to the nucleus. Targets of ubiquitin-proteasome regulation include unimported chloroplast precursor proteins in the cytosol, protein translocation machinery at the chloroplast surface, and transcription factors in the nucleus. This review will focus on the mechanism through which the ubiquitin-proteasome system optimizes plastid biogenesis and plant development through the regulation of nuclear-plastid interactions.
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Affiliation(s)
- Yoshihiro Hirosawa
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of MiyazakiMiyazaki, Japan
| | - Yasuko Ito-Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of MiyazakiMiyazaki, Japan
- Organization for Promotion of Tenure Track, University of MiyazakiMiyazaki, Japan
| | - Takehito Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of MiyazakiMiyazaki, Japan
- *Correspondence: Takehito Inaba,
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329
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Pierella Karlusich JJ, Zurbriggen MD, Shahinnia F, Sonnewald S, Sonnewald U, Hosseini SA, Hajirezaei MR, Carrillo N. Chloroplast Redox Status Modulates Genome-Wide Plant Responses during the Non-host Interaction of Tobacco with the Hemibiotrophic Bacterium Xanthomonas campestris pv. vesicatoria. FRONTIERS IN PLANT SCIENCE 2017; 8:1158. [PMID: 28725231 PMCID: PMC5495832 DOI: 10.3389/fpls.2017.01158] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/16/2017] [Indexed: 05/05/2023]
Abstract
Non-host resistance is the most ample and durable form of plant resistance against pathogen infection. It includes induction of defense-associated genes, massive metabolic reprogramming, and in many instances, a form of localized cell death (LCD) at the site of infection, purportedly designed to limit the spread of biotrophic and hemibiotrophic microorganisms. Reactive oxygen species (ROS) have been proposed to act as signals for LCD orchestration. They are produced in various cellular compartments including chloroplasts, mitochondria and apoplast. We have previously reported that down-regulation of ROS build-up in chloroplasts by expression of a plastid-targeted flavodoxin (Fld) suppressed LCD in tobacco leaves inoculated with the non-host bacterium Xanthomonas campestris pv. vesicatoria (Xcv), while other defensive responses were unaffected, suggesting that chloroplast ROS and/or redox status play a major role in the progress of LCD. To better understand these effects, we compare here the transcriptomic alterations caused by Xcv inoculation on leaves of Fld-expressing tobacco plants and their wild-type siblings. About 29% of leaf-expressed genes were affected by Xcv and/or Fld. Surprisingly, 5.8% of them (1,111 genes) were regulated by Fld in the absence of infection, presumably representing pathways responsive to chloroplast ROS production and/or redox status during normal growth conditions. While the majority (∼75%) of pathogen-responsive genes were not affected by Fld, many Xcv responses were exacerbated, attenuated, or regulated in opposite direction by expression of this protein. Particularly interesting was a group of 384 genes displaying Xcv responses that were already triggered by Fld in the absence of infection, suggesting that the transgenic plants had a larger and more diversified suite of constitutive defenses against the attacking microorganism compared to the wild type. Fld modulated many genes involved in pathogenesis, signal transduction, transcriptional regulation and hormone-based pathways. Remarkable interactions with proteasomal protein degradation were observed. The results provide the first genome-wide, comprehensive picture illustrating the relevance of chloroplast redox status in biotic stress responses.
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Affiliation(s)
- Juan J. Pierella Karlusich
- Instituto de Biología Molecular y Celular de Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de RosarioRosario, Argentina
| | - Matias D. Zurbriggen
- Instituto de Biología Molecular y Celular de Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de RosarioRosario, Argentina
| | - Fahimeh Shahinnia
- Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
| | - Sophia Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-NurembergErlangen, Germany
| | - Uwe Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-NurembergErlangen, Germany
| | - Seyed A. Hosseini
- Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant ResearchGatersleben, Germany
- *Correspondence: Mohammad-Reza Hajirezaei, Néstor Carrillo,
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de RosarioRosario, Argentina
- *Correspondence: Mohammad-Reza Hajirezaei, Néstor Carrillo,
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330
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Erickson JL, Kantek M, Schattat MH. Plastid-Nucleus Distance Alters the Behavior of Stromules. FRONTIERS IN PLANT SCIENCE 2017; 8:1135. [PMID: 28729870 PMCID: PMC5498514 DOI: 10.3389/fpls.2017.01135] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/13/2017] [Indexed: 05/20/2023]
Abstract
Plastids send "retrograde" signals to the nucleus to deliver information regarding their physiological status. One open question concerning this signal transfer is how the signal bridges the cytoplasm. Based on individual reports of plastid derived tubular membrane extensions connecting to nuclei, these so-called stromules have been suggested to function as communication routes between plastids and nuclei in response to biotic stress. However, based on the data currently available it is unclear whether interactions between stromules and nuclei are truly intentional or observed as a result of an inflated stromule frequency throughout the cell, and are thus a random event. The source of this uncertainty stems from missing information regarding the relative distribution of all plastids and stromules within a given cell. A comprehensive analysis of the upper epidermis of Arabidopsis thaliana rosette leaves was performed via a combination of still images and time-lapse movies of stromule formation in the context of the whole cell. This analysis could definitively confirm that stromule formation is not evenly distributed. Stromules are significantly more frequent within 8 μm of the nucleus, and approximately 90% of said stromules formed facing the nucleus. Time-lapse movies revealed that this enrichment of stromules is achieved via a 10-fold higher frequency of stromule initiation events within this 8 μm zone compared to the cell periphery. Following the movement of plastids and nuclei it became evident that movement and formation of stromules is correlated to nucleus movement. Observations suggest that stromules "connecting" to the nucleus are not necessarily the result of plastids sensing the nucleus and reaching out toward it, but are rather pulled out of the surface of nucleus associated plastids during opposing movement of these two organelles. This finding does not exclude the possibility that stromules could be transferring signals to the nucleus. However, this work provides support for an alternative hypothesis to explain stromule-nuclear interactions, suggesting that the main purpose of nucleus associated stromules may be to ensure a certain number of plastids maintain contact with the constantly moving nucleus.
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331
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Susila H, Jin S, Ahn JH. Light Intensity and Floral Transition: Chloroplast Says "Time to Flower!". MOLECULAR PLANT 2016; 9:1551-1553. [PMID: 27793786 DOI: 10.1016/j.molp.2016.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 10/06/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Hendry Susila
- Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 02841, South Korea
| | - Suhyun Jin
- Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 02841, South Korea
| | - Ji Hoon Ahn
- Creative Research Initiatives, Department of Life Sciences, Korea University, Seoul 02841, South Korea.
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332
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Li L, Kubiszewski-Jakubiak S, Radomiljac J, Wang Y, Law SR, Keech O, Narsai R, Berkowitz O, Duncan O, Murcha MW, Whelan J. Characterization of a novel β-barrel protein (AtOM47) from the mitochondrial outer membrane of Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:6061-6075. [PMID: 27811077 PMCID: PMC5100019 DOI: 10.1093/jxb/erw366] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In plant cells, mitochondria are major providers of energy and building blocks for growth and development as well as abiotic and biotic stress responses. They are encircled by two lipid membranes containing proteins that control mitochondrial function through the import of macromolecules and metabolites. Characterization of a novel β-barrel protein, OUTER MEMBRANE PROTEIN 47 (OM47), unique to the green lineage and related to the voltage-dependent anion channel (VDAC) protein family, showed that OM47 can complement a VDAC mutant in yeast. Mutation of OM47 in Arabidopsis thaliana by T-DNA insertion had no effect on the import of proteins, such as the β-barrel proteins translocase of the outer membrane 40 (TOM40) or sorting and assembly machinery 50 (SAM50), into mitochondria. Molecular and physiological analyses revealed a delay in chlorophyll breakdown, higher levels of starch, and a delay in the induction of senescence marker genes in the mutant lines. While there was a reduction of >90% in OM47 protein in mitochondria isolated from 3-week-old om47 mutants, in mitochondria isolated from 8-week-old plants OM47 levels were similar to that of the wild type. This recovery was achieved by an up-regulation of OM47 transcript abundance in the mutants. Combined, these results highlight a role in leaf senescence for this plant-specific β-barrel protein, probably mediating the recovery and recycling of chloroplast breakdown products by transporting metabolic intermediates into and out of mitochondria.
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Affiliation(s)
- Lu Li
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Szymon Kubiszewski-Jakubiak
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009 Australia
| | - Jordan Radomiljac
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Yan Wang
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Simon R Law
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, S-90187 Umeå, Sweden
| | - Olivier Keech
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, S-90187 Umeå, Sweden
| | - Reena Narsai
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Oliver Berkowitz
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Owen Duncan
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009 Australia
| | - Monika W Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009 Australia
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
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333
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Van Aken O, Ford E, Lister R, Huang S, Millar AH. Retrograde signalling caused by heritable mitochondrial dysfunction is partially mediated by ANAC017 and improves plant performance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:542-558. [PMID: 27425258 DOI: 10.1111/tpj.13276] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Mitochondria are crucial for plant viability and are able to communicate information on their functional status to the cellular nucleus via retrograde signalling, thereby affecting gene expression. It is currently unclear if retrograde signalling in response to constitutive mitochondrial biogenesis defects is mediated by the same pathways as those triggered during acute mitochondrial dysfunction. Furthermore, it is unknown if retrograde signalling can effectively improve plant performance when mitochondrial function is constitutively impaired. Here we show that retrograde signalling in mutants defective in mitochondrial proteins RNA polymerase rpotmp or prohibitin atphb3 can be suppressed by knocking out the transcription factor ANAC017. Genome-wide RNA-seq expression analysis revealed that ANAC017 is almost solely responsible for the most dramatic transcriptional changes common to rpotmp and atphb3 mutants, regulating classical marker genes such as alternative oxidase 1a (AOX1a) and also previously-uncharacterised DUF295 genes that appear to be new retrograde markers. In contrast, ANAC017 does not regulate intra-mitochondrial gene expression or transcriptional changes unique to either rpotmp or atphb3 genotype, suggesting the existence of currently unknown signalling cascades. The data show that ANAC017 function extends beyond common retrograde transcriptional responses and affects downstream protein abundance and enzyme activity of alternative oxidase, as well as steady-state energy metabolism in atphb3 plants. Furthermore, detailed growth analysis revealed that ANAC017-dependent retrograde signalling provides benefits for growth and productivity in plants with mitochondrial defects. In conclusion, ANAC017 plays a key role in both biogenic and operational mitochondrial retrograde signalling, and improves plant performance when mitochondrial function is constitutively impaired.
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Affiliation(s)
- Olivier Van Aken
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Ethan Ford
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Ryan Lister
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Shaobai Huang
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - A Harvey Millar
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
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334
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Burgess SJ, Granero-Moya I, Grangé-Guermente MJ, Boursnell C, Terry MJ, Hibberd JM. Ancestral light and chloroplast regulation form the foundations for C 4 gene expression. NATURE PLANTS 2016; 2:16161. [PMID: 27748771 DOI: 10.1038/nplants.2016.161] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
C4 photosynthesis acts as a carbon concentrating mechanism that leads to large increases in photosynthetic efficiency. The C4 pathway is found in more than 60 plant lineages1 but the molecular enablers of this evolution are poorly understood. In particular, it is unclear how non-photosynthetic proteins in the ancestral C3 system have repeatedly become strongly expressed and integrated into photosynthesis gene regulatory networks in C4 leaves. Here, we provide clear evidence that in C3 leaves, genes encoding key enzymes of the C4 pathway are already co-regulated with photosynthesis genes and are controlled by both light and chloroplast-to-nucleus signalling. In C4 leaves this regulation becomes increasingly dependent on the chloroplast. We propose that regulation of C4 cycle genes by light and the chloroplast in the ancestral C3 state has facilitated the repeated evolution of the complex and convergent C4 trait.
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Affiliation(s)
- Steven J Burgess
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Ignasi Granero-Moya
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | | | - Chris Boursnell
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Matthew J Terry
- Biological Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Julian M Hibberd
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
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335
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Woodson JD. Chloroplast quality control - balancing energy production and stress. THE NEW PHYTOLOGIST 2016; 212:36-41. [PMID: 27533783 DOI: 10.1111/nph.14134] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/13/2016] [Indexed: 05/07/2023]
Abstract
Contents 36 I. 36 II. 37 III. 37 IV. 38 V. 39 VI. 40 VII. 40 40 References 40 SUMMARY: All organisms require the ability to sense their surroundings and adapt. Such capabilities allow them to thrive in a wide range of habitats. This is especially true for plants, which are sessile and have to be genetically equipped to withstand every change in their environment. Plants and other eukaryotes use their energy-producing organelles (i.e. mitochondria and chloroplasts) as such sensors. In response to a changing cellular or external environment, these organelles can emit 'retrograde' signals that alter gene expression and/or cell physiology. This signaling is important in plants, fungi, and animals and impacts diverse cellular functions including photosynthesis, energy production/storage, stress responses, growth, cell death, ageing, and tumor progression. Originally, chloroplast retrograde signals in plants were known to lead to the reprogramming of nuclear transcription. New research, however, has pointed to additional posttranslational mechanisms that lead to chloroplast regulation and turnover in response to stress. Such mechanisms involve singlet oxygen, ubiquitination, the 26S proteasome, and cellular degradation machinery.
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Affiliation(s)
- Jesse D Woodson
- Plant Biology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA
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Wilson ME, Mixdorf M, Berg RH, Haswell ES. Plastid osmotic stress influences cell differentiation at the plant shoot apex. Development 2016; 143:3382-93. [PMID: 27510974 DOI: 10.1242/dev.136234] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 08/02/2016] [Indexed: 01/05/2023]
Abstract
The balance between proliferation and differentiation in the plant shoot apical meristem is controlled by regulatory loops involving the phytohormone cytokinin and stem cell identity genes. Concurrently, cellular differentiation in the developing shoot is coordinated with the environmental and developmental status of plastids within those cells. Here, we employ an Arabidopsis thaliana mutant exhibiting constitutive plastid osmotic stress to investigate the molecular and genetic pathways connecting plastid osmotic stress with cell differentiation at the shoot apex. msl2 msl3 mutants exhibit dramatically enlarged and deformed plastids in the shoot apical meristem, and develop a mass of callus tissue at the shoot apex. Callus production in this mutant requires the cytokinin receptor AHK2 and is characterized by increased cytokinin levels, downregulation of cytokinin signaling inhibitors ARR7 and ARR15, and induction of the stem cell identity gene WUSCHEL Furthermore, plastid stress-induced apical callus production requires elevated plastidic reactive oxygen species, ABA biosynthesis, the retrograde signaling protein GUN1, and ABI4. These results are consistent with a model wherein the cytokinin/WUS pathway and retrograde signaling control cell differentiation at the shoot apex.
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Affiliation(s)
- Margaret E Wilson
- Department of Biology, Mailbox 1137, One Brookings Drive, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - Matthew Mixdorf
- Department of Biology, Mailbox 1137, One Brookings Drive, Washington University in Saint Louis, Saint Louis, MO 63130 USA
| | - R Howard Berg
- Integrated Microscopy Facility, Donald Danforth Plant Science Center, 975 North Warson Rd., Saint Louis, MO 63132 USA
| | - Elizabeth S Haswell
- Department of Biology, Mailbox 1137, One Brookings Drive, Washington University in Saint Louis, Saint Louis, MO 63130 USA
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Sensing and signaling of oxidative stress in chloroplasts by inactivation of the SAL1 phosphoadenosine phosphatase. Proc Natl Acad Sci U S A 2016; 113:E4567-76. [PMID: 27432987 PMCID: PMC4978270 DOI: 10.1073/pnas.1604936113] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Intracellular signaling during oxidative stress is complex, with organelle-to-nucleus retrograde communication pathways ill-defined or incomplete. Here we identify the 3'-phosphoadenosine 5'-phosphate (PAP) phosphatase SAL1 as a previously unidentified and conserved oxidative stress sensor in plant chloroplasts. Arabidopsis thaliana SAL1 (AtSAL1) senses changes in photosynthetic redox poise, hydrogen peroxide, and superoxide concentrations in chloroplasts via redox regulatory mechanisms. AtSAL1 phosphatase activity is suppressed by dimerization, intramolecular disulfide formation, and glutathionylation, allowing accumulation of its substrate, PAP, a chloroplast stress retrograde signal that regulates expression of plastid redox associated nuclear genes (PRANGs). This redox regulation of SAL1 for activation of chloroplast signaling is conserved in the plant kingdom, and the plant protein has evolved enhanced redox sensitivity compared with its yeast ortholog. Our results indicate that in addition to sulfur metabolism, SAL1 orthologs have evolved secondary functions in oxidative stress sensing in the plant kingdom.
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Grieco M, Jain A, Ebersberger I, Teige M. An evolutionary view on thylakoid protein phosphorylation uncovers novel phosphorylation hotspots with potential functional implications. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3883-96. [PMID: 27117338 DOI: 10.1093/jxb/erw164] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The regulation of photosynthetic light reactions by reversible protein phosphorylation is well established today, but functional studies have so far mostly been restricted to processes affecting light-harvesting complex II and the core proteins of photosystem II. Virtually no functional data are available on regulatory effects at the other photosynthetic complexes despite the identification of multiple phosphorylation sites. Therefore we summarize the available data from 50 published phospho-proteomics studies covering the main complexes involved in photosynthetic light reactions in the 'green lineage' (i.e. green algae and land plants) as well as its cyanobacterial counterparts. In addition, we performed an extensive orthologue search for the major photosynthetic thylakoid proteins in 41 sequenced genomes and generated sequence alignments to survey the phylogenetic distribution of phosphorylation sites and their evolutionary conservation from green algae to higher plants. We observed a number of uncharacterized phosphorylation hotspots at photosystem I and the ATP synthase with potential functional relevance as well as an unexpected divergence of phosphosites. Although technical limitations might account for a number of those differences, we think that many of these phosphosites have important functions. This is particularly important for mono- and dicot plants, where these sites might be involved in regulatory processes such as stress acclimation.
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Affiliation(s)
- Michele Grieco
- Department of Ecogenomics and Systems Biology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria
| | - Arpit Jain
- Department for Applied Bioinformatics, Institute for Cell Biology and Neuroscience, Goethe University, Max-von-Laue Str. 13, D-60438 Frankfurt, Germany
| | - Ingo Ebersberger
- Department for Applied Bioinformatics, Institute for Cell Biology and Neuroscience, Goethe University, Max-von-Laue Str. 13, D-60438 Frankfurt, Germany Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberg Anlage 25, D-60325 Frankfurt, Germany
| | - Markus Teige
- Department of Ecogenomics and Systems Biology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria
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Kmiecik P, Leonardelli M, Teige M. Novel connections in plant organellar signalling link different stress responses and signalling pathways. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3793-807. [PMID: 27053718 DOI: 10.1093/jxb/erw136] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To coordinate growth, development and responses to environmental stimuli, plant cells need to communicate the metabolic state between different sub-compartments of the cell. This requires signalling pathways, including protein kinases, secondary messengers such as Ca(2+) ions or reactive oxygen species (ROS) as well as metabolites and plant hormones. The signalling networks involved have been intensively studied over recent decades and have been elaborated more or less in detail. However, it has become evident that these signalling networks are also tightly interconnected and often merge at common targets such as a distinct group of transcription factors, most prominently ABI4, which are amenable to regulation by phosphorylation, potentially also in a Ca(2+)- or ROS-dependent fashion. Moreover, the signalling pathways connect several organelles or subcellular compartments, not only in functional but also in physical terms, linking for example chloroplasts to the nucleus or peroxisomes to chloroplasts thereby enabling physical routes for signalling by metabolite exchange or even protein translocation. Here we briefly discuss these novel findings and try to connect them in order to point out the remaining questions and emerging developments in plant organellar signalling.
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Affiliation(s)
- Przemyslaw Kmiecik
- Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Manuela Leonardelli
- Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Markus Teige
- Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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Bruggeman Q, Mazubert C, Prunier F, Lugan R, Chan KX, Phua SY, Pogson BJ, Krieger-Liszkay A, Delarue M, Benhamed M, Bergounioux C, Raynaud C. Chloroplast Activity and 3'phosphadenosine 5'phosphate Signaling Regulate Programmed Cell Death in Arabidopsis. PLANT PHYSIOLOGY 2016; 170:1745-56. [PMID: 26747283 PMCID: PMC4775142 DOI: 10.1104/pp.15.01872] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/05/2016] [Indexed: 05/21/2023]
Abstract
Programmed cell death (PCD) is a crucial process both for plant development and responses to biotic and abiotic stress. There is accumulating evidence that chloroplasts may play a central role during plant PCD as for mitochondria in animal cells, but it is still unclear whether they participate in PCD onset, execution, or both. To tackle this question, we have analyzed the contribution of chloroplast function to the cell death phenotype of the myoinositol phosphate synthase1 (mips1) mutant that forms spontaneous lesions in a light-dependent manner. We show that photosynthetically active chloroplasts are required for PCD to occur in mips1, but this process is independent of the redox state of the chloroplast. Systematic genetic analyses with retrograde signaling mutants reveal that 3'-phosphoadenosine 5'-phosphate, a chloroplast retrograde signal that modulates nuclear gene expression in response to stress, can inhibit cell death and compromises plant innate immunity via inhibition of the RNA-processing 5'-3' exoribonucleases. Our results provide evidence for the role of chloroplast-derived signal and RNA metabolism in the control of cell death and biotic stress response.
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Affiliation(s)
- Quentin Bruggeman
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Christelle Mazubert
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Florence Prunier
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Raphaël Lugan
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Kai Xun Chan
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Su Yin Phua
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Barry James Pogson
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Anja Krieger-Liszkay
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Marianne Delarue
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Moussa Benhamed
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Catherine Bergounioux
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
| | - Cécile Raynaud
- Institute of Plant Sciences Paris-Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, Bâtiment 630, 91405 Orsay, France (Q.B., C.M., F.P., M.D., M.B., C.B., C.R.);Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France (R.L.);Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia (K.X.C., S.Y.P., B.J.P.);Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique et aux Energies Alternatives Saclay, Centre National de la Recherche Scientifique, Université Paris-Sud, F-91191 Gif-sur-Yvette cedex, France (A.K.-L.); and Division of Biological and Environmental Sciences and Engineering and Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia (M.B.)
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Larkin RM. Tetrapyrrole Signaling in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:1586. [PMID: 27807442 PMCID: PMC5069423 DOI: 10.3389/fpls.2016.01586] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 10/07/2016] [Indexed: 05/03/2023]
Abstract
Tetrapyrroles make critical contributions to a number of important processes in diverse organisms. In plants, tetrapyrroles are essential for light signaling, the detoxification of reactive oxygen species, the assimilation of nitrate and sulfate, respiration, photosynthesis, and programed cell death. The misregulation of tetrapyrrole metabolism can produce toxic reactive oxygen species. Thus, it is not surprising that tetrapyrrole metabolism is strictly regulated and that tetrapyrrole metabolism affects signaling mechanisms that regulate gene expression. In plants and algae, tetrapyrroles are synthesized in plastids and were some of the first plastid signals demonstrated to regulate nuclear gene expression. In plants, the mechanism of tetrapyrrole-dependent plastid-to-nucleus signaling remains poorly understood. Additionally, some of experiments that tested ideas for possible signaling mechanisms appeared to produce conflicting data. In some instances, these conflicts are potentially explained by different experimental conditions. Although the biological function of tetrapyrrole signaling is poorly understood, there is compelling evidence that this signaling is significant. Specifically, this signaling appears to affect the accumulation of starch and may promote abiotic stress tolerance. Tetrapyrrole-dependent plastid-to-nucleus signaling interacts with a distinct plastid-to-nucleus signaling mechanism that depends on GENOMES UNCUOPLED1 (GUN1). GUN1 contributes to a variety of processes, such as chloroplast biogenesis, the circadian rhythm, abiotic stress tolerance, and development. Thus, the contribution of tetrapyrrole signaling to plant function is potentially broader than we currently appreciate. In this review, I discuss these aspects of tetrapyrrole signaling.
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Ibata H, Nagatani A, Mochizuki N. CHLH/GUN5 Function in Tetrapyrrole Metabolism Is Correlated with Plastid Signaling but not ABA Responses in Guard Cells. FRONTIERS IN PLANT SCIENCE 2016; 7:1650. [PMID: 27872634 PMCID: PMC5098175 DOI: 10.3389/fpls.2016.01650] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/20/2016] [Indexed: 05/20/2023]
Abstract
Expression of Photosynthesis-Associated Nuclear Genes (PhANGs) is controlled by environmental stimuli and plastid-derived signals ("plastid signals") transmitting the developmental and functional status of plastids to the nucleus. Arabidopsis genomes uncoupled (gun) mutants exhibit defects in plastid signaling, leading to ectopic expression of PhANGs in the absence of chloroplast development. GUN5 encodes the plastid-localized Mg-chelatase enzyme subunit (CHLH), and recent studies suggest that CHLH is a multifunctional protein involved in tetrapyrrole biosynthesis, plastid signaling and ABA responses in guard cells. To understand the basis of CHLH multifunctionality, we investigated 15 gun5 missense mutant alleles and transgenic lines expressing a series of truncated CHLH proteins in a severe gun5 allele (cch) background (tCHLHs, 10 different versions). Here, we show that Mg-chelatase function and plastid signaling are generally correlated; in contrast, based on the analysis of the gun5 missense mutant alleles, ABA-regulated stomatal control is distinct from these two other functions. We found that none of the tCHLHs could restore plastid-signaling or Mg-chelatase functions. Additionally, we found that both the C-terminal half and N-terminal half of CHLH function in ABA-induced stomatal movement.
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Colombo M, Tadini L, Peracchio C, Ferrari R, Pesaresi P. GUN1, a Jack-Of-All-Trades in Chloroplast Protein Homeostasis and Signaling. FRONTIERS IN PLANT SCIENCE 2016; 7:1427. [PMID: 27713755 PMCID: PMC5032792 DOI: 10.3389/fpls.2016.01427] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/07/2016] [Indexed: 05/04/2023]
Abstract
The GENOMES UNCOUPLED 1 (GUN1) gene has been reported to encode a chloroplast-localized pentatricopeptide-repeat protein, which acts to integrate multiple indicators of plastid developmental stage and altered plastid function, as part of chloroplast-to-nucleus retrograde communication. However, the molecular mechanisms underlying signal integration by GUN1 have remained elusive, up until the recent identification of a set of GUN1-interacting proteins, by co-immunoprecipitation and mass-spectrometric analyses, as well as protein-protein interaction assays. Here, we review the molecular functions of the different GUN1 partners and propose a major role for GUN1 as coordinator of chloroplast translation, protein import, and protein degradation. This regulatory role is implemented through proteins that, in most cases, are part of multimeric protein complexes and whose precise functions vary depending on their association states. Within this framework, GUN1 may act as a platform to promote specific functions by bringing the interacting enzymes into close proximity with their substrates, or may inhibit processes by sequestering particular pools of specific interactors. Furthermore, the interactions of GUN1 with enzymes of the tetrapyrrole biosynthesis (TPB) pathway support the involvement of tetrapyrroles as signaling molecules in retrograde communication.
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Affiliation(s)
- Monica Colombo
- Centro Ricerca e Innovazione, Fondazione Edmund MachSan Michele all'Adige, Italy
| | - Luca Tadini
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
| | - Carlotta Peracchio
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
| | - Roberto Ferrari
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
| | - Paolo Pesaresi
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
- *Correspondence: Paolo Pesaresi
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