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Doyle JJ. Defining coalescent genes: Theory meets practice in organelle phylogenomics. Syst Biol 2021; 71:476-489. [PMID: 34191012 DOI: 10.1093/sysbio/syab053] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
The species tree paradigm that dominates current molecular systematic practice infers species trees from collections of sequences under assumptions of the multispecies coalescent (MSC), i.e., that there is free recombination between the sequences and no (or very low) recombination within them. These coalescent genes (c-genes) are thus defined in an historical rather than molecular sense, and can in theory be as large as an entire genome or as small as a single nucleotide. A debate about how to define c-genes centers on the contention that nuclear gene sequences used in many coalescent analyses undergo too much recombination, such that their introns comprise multiple c-genes, violating a key assumption of the MSC. Recently a similar argument has been made for the genes of plastid (e.g., chloroplast) and mitochondrial genomes, which for the last 30 or more years have been considered to represent a single c-gene for the purposes of phylogeny reconstruction because they are non-recombining in a historical sense. Consequently, it has been suggested that these genomes should be analyzed using coalescent methods that treat their genes-over 70 protein-coding genes in the case of most plastid genomes (plastomes)-as independent estimates of species phylogeny, in contrast to the usual practice of concatenation, which is appropriate for generating gene trees. However, although recombination certainly occurs in the plastome, as has been recognized since the 1970's, it is unlikely to be phylogenetically relevant. This is because such historically effective recombination can only occur when plastomes with incongruent histories are brought together in the same plastid. However, plastids sort rapidly into different cell lineages and rarely fuse. Thus, because of plastid biology, the plastome is a more canonical c-gene than is the average multi-intron mammalian nuclear gene. The plastome should thus continue to be treated as a single estimate of the underlying species phylogeny, as should the mitochondrial genome. The implications of this long-held insight of molecular systematics for studies in the phylogenomic era are explored.
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Affiliation(s)
- Jeff J Doyle
- Plant Biology Section, Plant Breeding & Genetics Section, and L. H. Bailey Hortorium, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853 USA
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2
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Hertle AP, Haberl B, Bock R. Horizontal genome transfer by cell-to-cell travel of whole organelles. SCIENCE ADVANCES 2021; 7:7/1/eabd8215. [PMID: 33523859 PMCID: PMC7775762 DOI: 10.1126/sciadv.abd8215] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/04/2020] [Indexed: 05/10/2023]
Abstract
Recent work has revealed that both plants and animals transfer genomes between cells. In plants, horizontal transfer of entire plastid, mitochondrial, or nuclear genomes between species generates new combinations of nuclear and organellar genomes, or produces novel species that are allopolyploid. The mechanisms of genome transfer between cells are unknown. Here, we used grafting to identify the mechanisms involved in plastid genome transfer from plant to plant. We show that during proliferation of wound-induced callus, plastids dedifferentiate into small, highly motile, amoeboid organelles. Simultaneously, new intercellular connections emerge by localized cell wall disintegration, forming connective pores through which amoeboid plastids move into neighboring cells. Our work uncovers a pathway of organelle movement from cell to cell and provides a mechanistic framework for horizontal genome transfer.
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Affiliation(s)
- Alexander P Hertle
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Benedikt Haberl
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
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3
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Johnston IG. Tension and Resolution: Dynamic, Evolving Populations of Organelle Genomes within Plant Cells. MOLECULAR PLANT 2019; 12:764-783. [PMID: 30445187 DOI: 10.1016/j.molp.2018.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/25/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Mitochondria and plastids form dynamic, evolving populations physically embedded in the fluctuating environment of the plant cell. Their evolutionary heritage has shaped how the cell controls the genetic structure and the physical behavior of its organelle populations. While the specific genes involved in these processes are gradually being revealed, the governing principles underlying this controlled behavior remain poorly understood. As the genetic and physical dynamics of these organelles are central to bioenergetic performance and plant physiology, this challenges both fundamental biology and strategies to engineer better-performing plants. This article reviews current knowledge of the physical and genetic behavior of mitochondria and chloroplasts in plant cells. An overarching hypothesis is proposed whereby organelles face a tension between genetic robustness and individual control and responsiveness, and different species resolve this tension in different ways. As plants are immobile and thus subject to fluctuating environments, their organelles are proposed to favor individual responsiveness, sacrificing genetic robustness. Several notable features of plant organelles, including large genomes, mtDNA recombination, fragmented organelles, and plastid/mitochondrial differences may potentially be explained by this hypothesis. Finally, the ways that quantitative and systems biology can help shed light on the plethora of open questions in this field are highlighted.
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Affiliation(s)
- Iain G Johnston
- School of Biosciences, University of Birmingham, Birmingham, UK; Birmingham Institute for Forest Research, University of Birmingham, Birmingham, UK.
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4
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Delfosse K, Wozny MR, Barton KA, Mathur N, Griffiths N, Mathur J. Plastid Envelope-Localized Proteins Exhibit a Stochastic Spatiotemporal Relationship to Stromules. FRONTIERS IN PLANT SCIENCE 2018; 9:754. [PMID: 29915611 PMCID: PMC5995270 DOI: 10.3389/fpls.2018.00754] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/16/2018] [Indexed: 05/13/2023]
Abstract
UNLABELLED Plastids in the viridiplantae sporadically form thin tubules called stromules that increase the interactive surface between the plastid and the surrounding cytoplasm. Several recent publications that report observations of certain proteins localizing to the extensions have then used the observations to suggest stromule-specific functions. The mechanisms by which specific localizations on these transient and sporadically formed extensions might occur remain unclear. Previous studies have yet to address the spatiotemporal relationship between a particular protein localization pattern and its distribution on an extended stromules and/or the plastid body. Here, we have used discrete protein patches found in several transgenic plants as fiducial markers to investigate this relationship. While we consider the inner plastid envelope-membrane localized protein patches of the GLUCOSE 6-PHOSPHATE/PHOSPHATE TRANSLOCATOR1 and the TRIOSE-PHOSPHATE/ PHOSPHATE TRANSLOCATOR 1 as artifacts of fluorescent fusion protein over-expression, stromule formation is not compromised in the respective stable transgenic lines that maintain normal growth and development. Our analysis of chloroplasts in the transgenic lines in the Arabidopsis Columbia background, and in the arc6 mutant, under stromule-inducing conditions shows that the possibility of finding a particular protein-enriched domain on an extended stromule or on a region of the main plastid body is stochastic. Our observations provide insights on the behavior of chloroplasts, the relationship between stromules and the plastid-body and strongly challenge claims of stromule-specific functions based solely upon protein localization to plastid extensions. ONE SENTENCE SUMMARY Observations of the spatiotemporal relationship between plastid envelope localized fluorescent protein fusions of two sugar-phosphate transporters and stromules suggest a stochastic rather than specific localization pattern that questions the idea of independent functions for stromules.
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Mazzoni-Putman SM, Stepanova AN. A Plant Biologist's Toolbox to Study Translation. FRONTIERS IN PLANT SCIENCE 2018; 9:873. [PMID: 30013583 PMCID: PMC6036148 DOI: 10.3389/fpls.2018.00873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/04/2018] [Indexed: 05/03/2023]
Abstract
Across a broad range of species and biological questions, more and more studies are incorporating translation data to better assess how gene regulation occurs at the level of protein synthesis. The inclusion of translation data improves upon, and has been shown to be more accurate than, transcriptional studies alone. However, there are many different techniques available to measure translation and it can be difficult, especially for young or aspiring scientists, to determine which methods are best applied in specific situations. We have assembled this review in order to enhance the understanding and promote the utilization of translational methods in plant biology. We cover a broad range of methods to measure changes in global translation (e.g., radiolabeling, polysome profiling, or puromycylation), translation of single genes (e.g., fluorescent reporter constructs, toeprinting, or ribosome density mapping), sequencing-based methods to uncover the entire translatome (e.g., Ribo-seq or translating ribosome affinity purification), and mass spectrometry-based methods to identify changes in the proteome (e.g., stable isotope labeling by amino acids in cell culture or bioorthogonal noncanonical amino acid tagging). The benefits and limitations of each method are discussed with a particular note of how applications from other model systems might be extended for use in plants. In order to make this burgeoning field more accessible to students and newer scientists, our review includes an extensive glossary to define key terms.
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6
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Hirakawa T, Matsunaga S. Chromatin Tagging Systems Contribute to Live Imaging Analyses for Chromatin Dynamics. CYTOLOGIA 2016. [DOI: 10.1508/cytologia.81.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Takeshi Hirakawa
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science
| | - Sachihiro Matsunaga
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science
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7
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Borucki W, Bederska M, Sujkowska-Rybkowska M. Visualisation of plastid outgrowths in potato (Solanum tuberosum L.) tubers by carboxyfluorescein diacetate staining. PLANT CELL REPORTS 2015; 34:853-860. [PMID: 25627254 PMCID: PMC4405334 DOI: 10.1007/s00299-015-1748-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/12/2015] [Accepted: 01/17/2015] [Indexed: 05/29/2023]
Abstract
We describe two types of plastid outgrowths visualised in potato tubers after carboxyfluorescein diacetate staining. Probable esterase activity of the outgrowths has been demonstrated for the first time ever. Plastid outgrowths were observed in the phelloderm and storage parenchyma cells of red potato (S. tuberosum L. cv. Rosalinde) tubers after administration of carboxyfluorescein diacetate stain. Endogenous esterases cleaved off acetic groups to release membrane-unpermeable green fluorescing carboxyfluorescein which accumulated differentially in particular cell compartments. The intensive green fluorescence of carboxyfluorescein exhibited highly branched stromules (stroma-filled plastid tubular projections of the plastid envelope) and allowed distinguishing them within cytoplasmic strands of the phelloderm cells. Stromules (1) were directed towards the nucleus or (2) penetrated the whole cells through the cytoplasmic bands of highly vacuolated phelloderm cells. Those directed towards the nucleus were flattened and adhered to the nuclear envelope. Stromule-like interconnections between two parts of the same plastids (isthmuses) were also observed. We also documented the formation of another type of the stroma-filled plastid outgrowths, referred to here as protrusions, which differed from previously defined stromules in both morphology and esterase activity. Unlike stromules, the protrusions were found to be associated with developmental processes leading to starch accumulation in the storage parenchyma cells. These results strongly suggest that stromules and protrusions exhibit esterase activity. This has been demonstrated for the first time. Morphological and biochemical features as well as possible functions of stromules and protrusions are discussed below.
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Affiliation(s)
- Wojciech Borucki
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776, Warsaw, Poland,
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8
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Delfosse K, Wozny MR, Jaipargas EA, Barton KA, Anderson C, Mathur J. Fluorescent Protein Aided Insights on Plastids and their Extensions: A Critical Appraisal. FRONTIERS IN PLANT SCIENCE 2015; 6:1253. [PMID: 26834765 PMCID: PMC4719081 DOI: 10.3389/fpls.2015.01253] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 12/21/2015] [Indexed: 05/20/2023]
Abstract
Multi-colored fluorescent proteins targeted to plastids have provided new insights on the dynamic behavior of these organelles and their interactions with other cytoplasmic components and compartments. Sub-plastidic components such as thylakoids, stroma, the inner and outer membranes of the plastid envelope, nucleoids, plastoglobuli, and starch grains have been efficiently highlighted in living plant cells. In addition, stroma filled membrane extensions called stromules have drawn attention to the dynamic nature of the plastid and its interactions with the rest of the cell. Use of dual and triple fluorescent protein combinations has begun to reveal plastid interactions with mitochondria, the nucleus, the endoplasmic reticulum and F-actin and suggests integral roles of plastids in retrograde signaling, cell to cell communication as well as plant-pathogen interactions. While the rapid advances and insights achieved through fluorescent protein based research on plastids are commendable it is necessary to endorse meaningful observations but subject others to closer scrutiny. Here, in order to develop a better and more comprehensive understanding of plastids and their extensions we provide a critical appraisal of recent information that has been acquired using targeted fluorescent protein probes.
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9
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Bobik K, Burch-Smith TM. Chloroplast signaling within, between and beyond cells. FRONTIERS IN PLANT SCIENCE 2015; 6:781. [PMID: 26500659 PMCID: PMC4593955 DOI: 10.3389/fpls.2015.00781] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
The most conspicuous function of plastids is the oxygenic photosynthesis of chloroplasts, yet plastids are super-factories that produce a plethora of compounds that are indispensable for proper plant physiology and development. Given their origins as free-living prokaryotes, it is not surprising that plastids possess their own genomes whose expression is essential to plastid function. This semi-autonomous character of plastids requires the existence of sophisticated regulatory mechanisms that provide reliable communication between them and other cellular compartments. Such intracellular signaling is necessary for coordinating whole-cell responses to constantly varying environmental cues and cellular metabolic needs. This is achieved by plastids acting as receivers and transmitters of specific signals that coordinate expression of the nuclear and plastid genomes according to particular needs. In this review we will consider the so-called retrograde signaling occurring between plastids and nuclei, and between plastids and other organelles. Another important role of the plastid we will discuss is the involvement of plastid signaling in biotic and abiotic stress that, in addition to influencing retrograde signaling, has direct effects on several cellular compartments including the cell wall. We will also review recent evidence pointing to an intriguing function of chloroplasts in regulating intercellular symplasmic transport. Finally, we consider an intriguing yet less widely known aspect of plant biology, chloroplast signaling from the perspective of the entire plant. Thus, accumulating evidence highlights that chloroplasts, with their complex signaling pathways, provide a mechanism for exquisite regulation of plant development, metabolism and responses to the environment. As chloroplast processes are targeted for engineering for improved productivity the effect of such modifications on chloroplast signaling will have to be carefully considered in order to avoid unintended consequences on plant growth and development.
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Affiliation(s)
| | - Tessa M. Burch-Smith
- *Correspondence: Tessa M. Burch-Smith, Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, 1414 Cumberland Avenue, M407 Walters Life Science, Knoxville, TN 37932, USA,
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10
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Schattat MH, Barton KA, Mathur J. The myth of interconnected plastids and related phenomena. PROTOPLASMA 2015; 252:359-71. [PMID: 24965372 DOI: 10.1007/s00709-014-0666-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/12/2014] [Indexed: 05/08/2023]
Abstract
Studies spread over nearly two and a half centuries have identified the primary plastid in autotrophic algae and plants as a pleomorphic, multifunctional organelle comprising of a double-membrane envelope enclosing an organization of internal membranes submerged in a watery stroma. All plastid units have been observed extending and retracting thin stroma-filled tubules named stromules sporadically. Observations on living plant cells often convey the impression that stromules connect two or more independent plastids with each other. When photo-bleaching techniques were used to suggest that macromolecules such as the green fluorescent protein could flow between already interconnected plastids, for many people this impression changed to conviction. However, it was noticed only recently that the concept of protein flow between plastids rests solely on the words "interconnected plastids" for which details have never been provided. We have critically reviewed botanical literature dating back to the 1880s for understanding this term and the phenomena that have become associated with it. We find that while meticulously detailed ontogenic studies spanning nearly 150 years have established the plastid as a singular unit organelle, there is no experimental support for the idea that interconnected plastids exist under normal conditions of growth and development. In this review, while we consider several possibilities that might allow a single elongated plastid to be misinterpreted as two or more interconnected plastids, our final conclusion is that the concept of direct protein flow between plastids is based on an unfounded assumption.
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Affiliation(s)
- Martin H Schattat
- Martin-Luther-Universität Halle-Wittenberg Pflanzenphysiologie, Weinbergweg 10, 06120, Halle (Saale), Germany,
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11
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Lindner AC, Lang D, Seifert M, Podlešáková K, Novák O, Strnad M, Reski R, von Schwartzenberg K. Isopentenyltransferase-1 (IPT1) knockout in Physcomitrella together with phylogenetic analyses of IPTs provide insights into evolution of plant cytokinin biosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2533-43. [PMID: 24692654 PMCID: PMC4036517 DOI: 10.1093/jxb/eru142] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The moss Physcomitrella patens is part of an early divergent clade of land plants utilizing the plant hormone cytokinin for growth control. The rate-limiting step of cytokinin biosynthesis is mediated by isopentenyltransferases (IPTs), found in land plants either as adenylate-IPTs or as tRNA-IPTs. Although a dominant part of cytokinins in flowering plants are synthesized by adenylate-IPTs, the Physcomitrella genome only encodes homologues of tRNA-IPTs. This study therefore looked into the question of whether cytokinins in moss derive from tRNA exclusively. Targeted gene knockout of ipt1 (d|ipt1) along with localization studies revealed that the chloroplast-bound IPT1 was almost exclusively responsible for the A37 prenylation of tRNA in Physcomitrella. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based cytokinin profiling demonstrated that the total amount of all free cytokinins in tissue was almost unaffected. However, the knockout plants showed increased levels of the N (6) -isopentenyladenine (iP)- and trans-zeatin (tZ)-type cytokinins, considered to provide active forms, while cis-zeatin (cZ)-type cytokinins were reduced. The data provide evidence for an additional and unexpected tRNA-independent cytokinin biosynthetic pathway in moss. Comprehensive phylogenetic analysis indicates a diversification of tRNA-IPT-like genes in bryophytes probably related to additional functions.
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Affiliation(s)
- Ann-Cathrin Lindner
- University of Hamburg, Biocenter Klein Flottbek, Ohnhorststraße 18, D-22609 Hamburg, Germany
| | - Daniel Lang
- University of Freiburg, Faculty of Biology, Plant Biotechnology, Schaenzlestr. 1, D-79104 Freiburg, Germany
| | - Maike Seifert
- University of Hamburg, Biocenter Klein Flottbek, Ohnhorststraße 18, D-22609 Hamburg, Germany
| | - Kateřina Podlešáková
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic Palacký University, Department of Biochemistry, Šlechtitelů 11, 78371 Olomouc, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic
| | - Ralf Reski
- University of Freiburg, Faculty of Biology, Plant Biotechnology, Schaenzlestr. 1, D-79104 Freiburg, Germany FRIAS-Freiburg Institute for Advanced Studies, Freiburg, Germany BIOSS-Centre for Biological Signalling Studies, Freiburg, Germany
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12
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Jarvis P, López-Juez E. Biogenesis and homeostasis of chloroplasts and other plastids. Nat Rev Mol Cell Biol 2014; 14:787-802. [PMID: 24263360 DOI: 10.1038/nrm3702] [Citation(s) in RCA: 384] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chloroplasts are the organelles that define plants, and they are responsible for photosynthesis as well as numerous other functions. They are the ancestral members of a family of organelles known as plastids. Plastids are remarkably dynamic, existing in strikingly different forms that interconvert in response to developmental or environmental cues. The genetic system of this organelle and its coordination with the nucleocytosolic system, the import and routing of nucleus-encoded proteins, as well as organellar division all contribute to the biogenesis and homeostasis of plastids. They are controlled by the ubiquitin-proteasome system, which is part of a network of regulatory mechanisms that integrate plastid development into broader programmes of cellular and organismal development.
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Affiliation(s)
- Paul Jarvis
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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13
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Abstract
Plastid division is fundamental to the biology of plant cells. Division by binary fission entails the coordinated assembly and constriction of four concentric rings, two internal and two external to the organelle. The internal FtsZ ring and external dynamin-like ARC5/DRP5B ring are connected across the two envelopes by the membrane proteins ARC6, PARC6, PDV1, and PDV2. Assembly-stimulated GTPase activity drives constriction of the FtsZ and ARC5/DRP5B rings, which together with the plastid-dividing rings pull and squeeze the envelope membranes until the two daughter plastids are formed, with the final separation requiring additional proteins. The positioning of the division machinery is controlled by the chloroplast Min system, which confines FtsZ-ring formation to the plastid midpoint. The dynamic morphology of plastids, especially nongreen plastids, is also considered here, particularly in relation to the production of stromules and plastid-derived vesicles and their possible roles in cellular communication and plastid functionality.
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14
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Ishida H, Izumi M, Wada S, Makino A. Roles of autophagy in chloroplast recycling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:512-21. [PMID: 24269172 DOI: 10.1016/j.bbabio.2013.11.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/01/2013] [Accepted: 11/07/2013] [Indexed: 01/04/2023]
Abstract
Chloroplasts are the primary energy suppliers for plants, and much of the total leaf nitrogen is distributed to these organelles. During growth and reproduction, chloroplasts in turn represent a major source of nitrogen to be recovered from senescing leaves and used in newly-forming and storage organs. Chloroplast proteins also can be an alternative substrate for respiration under suboptimal conditions. Autophagy is a process of bulk degradation and nutrient sequestration that is conserved in all eukaryotes. Autophagy can selectively target chloroplasts as whole organelles and or as Rubisco-containing bodies that are enclosed by the envelope and specifically contain the stromal portion of the chloroplast. Although information is still limited, recent work indicates that chloroplast recycling via autophagy plays important roles not only in developmental processes but also in organelle quality control and adaptation to changing environments. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Hiroyuki Ishida
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
| | - Masanori Izumi
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shinya Wada
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | - Amane Makino
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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15
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Pyke KA. Divide and shape: an endosymbiont in action. PLANTA 2013; 237:381-7. [PMID: 22910876 DOI: 10.1007/s00425-012-1739-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/03/2012] [Indexed: 05/10/2023]
Abstract
The endosymbiotic evolution of the plastid within the host cell required development of a mechanism for efficient division of the plastid. Whilst a model for the mechanism of chloroplast division has been constructed, little is known of how other types of plastids divide, especially the proplastid, the progenitor of all plastid types in the cell. It has become clear that plastid shape is highly heterogeneous and dynamic, especially stromules. This article considers how such variation in morphology might be controlled and how such plastids might divide efficiently.
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Affiliation(s)
- Kevin A Pyke
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.
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16
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Schattat MH, Klösgen RB, Mathur J. New insights on stromules: stroma filled tubules extended by independent plastids. PLANT SIGNALING & BEHAVIOR 2012; 7:1132-7. [PMID: 22899053 PMCID: PMC3489645 DOI: 10.4161/psb.21342] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The recognition of stromules as sporadically extended stroma filled tubules from all kinds of plastids constitutes one of the major insights that resulted from the direct application of green fluorescent protein aided imaging of living plant cells. Observations of dynamic green fluorescent stromules strongly suggested that plastids frequently interact with each other while photo-bleaching of interconnected plastids indicated that proteins can move within the stroma filled tubules. These observations readily fit into the prevailing concept of the endosymbiogenic origins of plastids and provided stromules the status of conduits for inter-plastid communication and macromolecule transfer. However, experimental evidence obtained recently through the use of photoconvertible protein labeled stromules strongly supports plastid independence rather than their interconnectivity. Additional information on stress conditions inducing stromules and observations on their alignment with other organelles suggests that the major role of stromules is to increase the interactive surface of a plastid with the rest of the cytoplasm.
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Affiliation(s)
- Martin H. Schattat
- Laboratory of Plant Development and Interactions; Department of Molecular and Cellular Biology; University of Guelph; Guelph, ON Canada
- Institut für Biologie-Pflanzenphysiologie; Martin-Luther-Universität; Halle Wittenberg; Halle/Saale, Germany
- The Sainsbury Laboratory; Norwich Research Park; Norwich, UK
| | - Ralf Bernd Klösgen
- Institut für Biologie-Pflanzenphysiologie; Martin-Luther-Universität; Halle Wittenberg; Halle/Saale, Germany
| | - Jaideep Mathur
- Laboratory of Plant Development and Interactions; Department of Molecular and Cellular Biology; University of Guelph; Guelph, ON Canada
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Abstract
Our objective was to test whether or not plastids and mitochondria, the two DNA-containing organelles, move between cells in plants. As our experimental approach, we grafted two different species of tobacco, Nicotiana tabacum and Nicotiana sylvestris. Grafting triggers formation of new cell-to-cell contacts, creating an opportunity to detect cell-to-cell organelle movement between the genetically distinct plants. We initiated tissue culture from sliced graft junctions and selected for clonal lines in which gentamycin resistance encoded in the N. tabacum nucleus was combined with spectinomycin resistance encoded in N. sylvestris plastids. Here, we present evidence for cell-to-cell movement of the entire 161-kb plastid genome in these plants, most likely in intact plastids. We also found that the related mitochondria were absent, suggesting independent movement of the two DNA-containing organelles. Acquisition of plastids from neighboring cells provides a mechanism by which cells may be repopulated with functioning organelles. Our finding supports the universality of intercellular organelle trafficking and may enable development of future biotechnological applications.
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Affiliation(s)
- Gregory Thyssen
- Waksman Institute, Rutgers University, Piscataway, NJ 08854; and
| | - Zora Svab
- Waksman Institute, Rutgers University, Piscataway, NJ 08854; and
| | - Pal Maliga
- Waksman Institute, Rutgers University, Piscataway, NJ 08854; and
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901
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