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Journal of Experimental Botany Feb 2012Lipid droplets called plastoglobules (PGs) exist in most plant tissues and plastid types. In chloroplasts, the polar lipid monolayer surrounding these low-density... (Review)
Review
Lipid droplets called plastoglobules (PGs) exist in most plant tissues and plastid types. In chloroplasts, the polar lipid monolayer surrounding these low-density lipoprotein particles is continuous with the outer lipid leaflet of the thylakoid membrane. Often small clusters of two or three PGs, only one of them directly connected to thylakoids, are present. Structural proteins (known as plastid-lipid associated proteins/fibrillins or plastoglobulins) together with lipid metabolic enzymes coat the PGs. The hydrophobic core of PGs contains a range of neutral lipids including the prenylquinones [tocopherols (vitamin E), phylloquinone (vitamin K(1)), and plastoquinone (PQ-9)]. In this review the function of PGs and their associated enzymes in prenylquinone metabolism will be discussed.
Topics: Chloroplasts; Lipid Metabolism; Lipids; Lipoproteins; Plant Proteins; Plants; Plastids; Quinones; Signal Transduction; Vitamin E; Vitamin K 1
PubMed: 22371323
DOI: 10.1093/jxb/ers016 -
Methods in Molecular Biology (Clifton,... 2018Chloroplasts are essential organelles that are responsible for photosynthesis in a wide range of organisms that have colonized all biotopes on Earth such as plants and... (Review)
Review
Chloroplasts are essential organelles that are responsible for photosynthesis in a wide range of organisms that have colonized all biotopes on Earth such as plants and unicellular algae. Interestingly, a secondary endosymbiotic event of a red algal ancestor gave rise to a group of organisms that have adopted an obligate parasitic lifestyle named Apicomplexa parasites. Apicomplexa parasites are some of the most widespread and poorly controlled pathogens in the world. These infectious agents are responsible for major human diseases such as toxoplasmosis, caused by Toxoplasma gondii, and malaria caused by Plasmodium spp. Most of these parasites harbor this relict plastid named the apicoplast, which is essential for parasite survival. The apicoplast has lost photosynthetic capacities but are metabolically similar to plant and algal chloroplasts. The apicoplast is considered a novel and important drug target against Apicomplexa parasites. This chapter focuses on the apicoplast of apicomplexa parasites, its maintenance, and its metabolic pathways.
Topics: Antiparasitic Agents; Apicoplasts; Drug Development; Energy Metabolism; Genome; Malaria; Metabolic Networks and Pathways; Photosynthesis; Plastids; Protein Transport; Symbiosis
PubMed: 29987713
DOI: 10.1007/978-1-4939-8654-5_3 -
Biochimica Et Biophysica Acta Sep 2015Plastids, such as chloroplasts, are widely distributed endosymbiotic organelles in plants and algae. Apart from their well-known functions in photosynthesis, they have... (Review)
Review
Plastids, such as chloroplasts, are widely distributed endosymbiotic organelles in plants and algae. Apart from their well-known functions in photosynthesis, they have roles in processes as diverse as signal sensing, fruit ripening, and seed development. As most plastid proteins are produced in the cytosol, plastids have developed dedicated translocon machineries for protein import, comprising the TOC (translocon at the outer envelope membrane of chloroplasts) and TIC (translocon at the inner envelope membrane of chloroplasts) complexes. Multiple lines of evidence reveal that protein import via the TOC complex is actively regulated, based on the specific interplay between distinct receptor isoforms and diverse client proteins. In this review, we summarize recent advances in our understanding of protein import regulation, particularly in relation to control by the ubiquitin-proteasome system (UPS), and how such regulation changes plastid development. The diversity of plastid import receptors (and of corresponding preprotein substrates) has a determining role in plastid differentiation and interconversion. The controllable turnover of TOC components by the UPS influences the developmental fate of plastids, which is fundamentally linked to plant development. Understanding the mechanisms by which plastid protein import is controlled is critical to the development of breakthrough approaches to increase the yield, quality and stress tolerance of important crop plants, which are highly dependent on plastid development. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
Topics: Chloroplast Proteins; Plastids; Proteasome Endopeptidase Complex; Protein Transport; Ubiquitin; Ubiquitination
PubMed: 25762164
DOI: 10.1016/j.bbabio.2015.02.017 -
Biochimica Et Biophysica Acta Feb 2013The presence of genes encoding organellar proteins in both the nucleus and the organelle necessitates tight coordination of expression by the different genomes, and this... (Review)
Review
The presence of genes encoding organellar proteins in both the nucleus and the organelle necessitates tight coordination of expression by the different genomes, and this has led to the evolution of sophisticated intracellular signaling networks. Organelle-to-nucleus signaling, or retrograde control, coordinates the expression of nuclear genes encoding organellar proteins with the metabolic and developmental state of the organelle. Complex networks of retrograde signals orchestrate major changes in nuclear gene expression and coordinate cellular activities and assist the cell during plant development and stress responses. It has become clear that, even though the chloroplast depends on the nucleus for its function, plastid signals play important roles in an array of different cellular processes vital to the plant. Hence, the chloroplast exerts significant control over the running of the cell. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids.
Topics: Cell Communication; Cell Nucleus; Plant Cells; Plant Proteins; Plastids; Protein Transport; Signal Transduction
PubMed: 22749883
DOI: 10.1016/j.bbamcr.2012.06.020 -
Journal of Phycology Apr 2021The purpose of this study was to establish a plastid transformation system for expressing recombinant proteins in Nannochloropsis gaditana. On the basis of the sequenced...
The purpose of this study was to establish a plastid transformation system for expressing recombinant proteins in Nannochloropsis gaditana. On the basis of the sequenced plastid genome, the homologous flanking region, 16S-trnI/trnA-23S, and the endogenous regulatory fragments containing the psbA promoter, rbcL promoter, rbcL terminator, and psbA terminator were amplified from N. gaditana as elements of a plastid transformation vector. Then, the herbicide-resistant gene (bar) was used as a selectable marker, regulated by the psbA promoter and rbcL terminator. Finally, two codon-optimized antimicrobial peptide-coding genes linked by endogenous ribosome binding site (RBS) in a polycistron were inserted into the constructed vector under the regulation of the rbcL promoter and psbA terminator. After microparticle bombardment, the positive clones were detected using polymerase chain reaction (PCR), and Southern and Western blotting were used to assess the co-expression of the two antimicrobial peptides from the plastid. Nannochloropsis gaditana showed the potential to express recombinant proteins for biotechnological applications, for example, for the development of oral vaccines in aquaculture.
Topics: Peptides; Plants; Plastids; Recombinant Proteins; Stramenopiles
PubMed: 33174215
DOI: 10.1111/jpy.13099 -
Methods in Molecular Biology (Clifton,... 2022As immobile organisms, green plants must be frequently challenged by a broad range of environmental stresses. During these constantly adverse conditions, reactive oxygen...
As immobile organisms, green plants must be frequently challenged by a broad range of environmental stresses. During these constantly adverse conditions, reactive oxygen species (ROS) levels can rise extremely in plants, leading to cellular dysfunction and cell death presumably due to irreversible protein overoxidation. Once considered merely as deleterious molecules, cells seek to remove them as efficiently as possible. To enhance ROS scavenging capacity, genes encoding antioxidative enzymes can be directly expressed from the genome of plastid (chloroplast), a major compartment for ROS production in photosynthetic organisms. Thus, overexpression of antioxidant enzymes by plastid engineering may provide an alternative to enhance plant's tolerance to stressful conditions specifically related with chloroplast-derived ROS. Here, we describe basic procedures for expressing glutathione reductase, a vital component of ascorbate-glutathione pathway, in tobacco via plastid transformation technology.
Topics: Antioxidants; Chloroplasts; Plants, Genetically Modified; Plastids; Reactive Oxygen Species
PubMed: 35657508
DOI: 10.1007/978-1-0716-2469-2_1 -
Proceedings of the National Academy of... Apr 2019The division of life into producers and consumers is blurred by evolution. For example, eukaryotic phototrophs can lose the capacity to photosynthesize, although they...
The division of life into producers and consumers is blurred by evolution. For example, eukaryotic phototrophs can lose the capacity to photosynthesize, although they may retain vestigial plastids that perform other essential cellular functions. Chrysophyte algae have undergone a particularly large number of photosynthesis losses. Here, we present a plastid genome sequence from a nonphotosynthetic chrysophyte, "" sp. NIES-1846, and show that it has retained a nearly identical set of plastid-encoded functions as apicomplexan parasites. Our transcriptomic analysis of 12 different photosynthetic and nonphotosynthetic chrysophyte lineages reveals remarkable convergence in the functions of these nonphotosynthetic plastids, along with informative lineage-specific retentions and losses. At one extreme, retains many photosynthesis-associated proteins, although it appears to have lost the reductive pentose phosphate pathway and most plastid amino acid metabolism pathways. At the other extreme, lacks plastid-targeted proteins associated with gene expression and all metabolic pathways that require plastid-encoded partners, indicating a complete loss of plastid DNA in this genus. Intriguingly, some of the nucleus-encoded proteins that once functioned in the expression of the plastid genome have been retained. These proteins were likely to have been dual targeted to the plastid and mitochondria of the chrysophyte ancestor, and are uniquely targeted to the mitochondria in Our comparative analyses provide insights into the process of functional reduction in nonphotosynthetic plastids.
Topics: Chloroplast Proteins; Chrysophyta; Evolution, Molecular; Gene Expression Profiling; Gene Expression Regulation; Genome, Plastid; Plastids
PubMed: 30872488
DOI: 10.1073/pnas.1819976116 -
The Plant Journal : For Cell and... Aug 2023The modification of photosynthesis-related genes in plastid genomes may improve crop yields. Recently, we reported that a plastid-targeting base editor named ptpTALECD,...
The modification of photosynthesis-related genes in plastid genomes may improve crop yields. Recently, we reported that a plastid-targeting base editor named ptpTALECD, in which a cytidine deaminase DddA functions as the catalytic domain, can homoplasmically substitute a targeted C to T in plastid genomes of Arabidopsis thaliana. However, some target Cs were not substituted. In addition, although ptpTALECD could substitute Cs on the 3' side of T and A, it was unclear whether it could also substitute Cs on the 3' side of G and C. In this study, we identified the preferential positions of the substituted Cs in ptpTALECD-targeting sequences in the Arabidopsis plastid genome. We also found that ptpTALECD could substitute Cs on the 3' side of all four bases in plastid genomes of Arabidopsis. More recently, a base editor containing an improved version of DddA (DddA11) was reported to substitute Cs more efficiently, and to substitute Cs on the 3' side of more varieties of bases in human mitochondrial genomes than a base editor containing DddA. Here, we also show that ptpTALECD_v2, in which a modified version of DddA11 functions as the catalytic domain, more frequently substituted Cs than ptpTALECD in the Arabidopsis plastid genome. We also found that ptpTALECD_v2 tended to substitute Cs at more positions than ptpTALECD. Our results reveal that ptpTALECD can cause a greater variety of codon changes and amino acid substitutions than previously thought, and that ptpTALECD and ptpTALECD_v2 are useful tools for the targeted base editing of plastid genomes.
Topics: Humans; Arabidopsis; Arabidopsis Proteins; Mitochondria; Plastids; Genome, Plastid
PubMed: 37265080
DOI: 10.1111/tpj.16311 -
Journal of Microscopy May 2004Investigation of plastids via green fluorescent protein (GFP) has led to the rediscovery of tubular extensions of the plastid membrane, termed stromules, for... (Review)
Review
Investigation of plastids via green fluorescent protein (GFP) has led to the rediscovery of tubular extensions of the plastid membrane, termed stromules, for stroma-filled tubules. These unique structures are challenging our understanding of plastid structure and function. Stromules are highly dynamic, branching and elongating across the plant cell. Recent experiments indicate that cytoplasmic microtubules and microfilaments control the shape and motility of stromules. Whether stromule formation involves plastid-specific structural systems, such as the plastid division machinery, remains open to debate. Fluorescence photobleaching experiments have revealed that GFP can traffic between plastids joined by stromules. As a result, interest has grown in whether other macromolecules can also travel through these connections. Although the function of stromules is unknown, several aspects of their biology suggest they play a role in molecular exchange between plastids and other organelles.
Topics: Arabidopsis Proteins; Chloroplasts; Dynamins; Green Fluorescent Proteins; Intracellular Membranes; Luminescent Proteins; Macromolecular Substances; Membrane Proteins; Movement; Plant Proteins; Plants; Plastids; Recombinant Fusion Proteins
PubMed: 15102061
DOI: 10.1111/j.0022-2720.2004.01317.x -
International Review of Cell and... 2011Plastids are a diverse group of organelles found in plants and some parasites. Because genes encoding plastid proteins are divided between the nuclear and plastid... (Review)
Review
Plastids are a diverse group of organelles found in plants and some parasites. Because genes encoding plastid proteins are divided between the nuclear and plastid genomes, coordinated expression of genes in two separate genomes is indispensable for plastid function. To coordinate nuclear gene expression with the functional or metabolic state of plastids, plant cells have acquired a retrograde signaling pathway from plastid to nucleus, also known as the plastid signaling pathway. To date, several metabolic processes within plastids have been shown to affect the expression of nuclear genes. Recent progress in this field has also revealed that the plastid signaling pathway interacts and shares common components with other intracellular signaling pathways. This review summarizes our current knowledge on retrograde signaling from plastid to nucleus in plant cells and its role in plant growth and development.
Topics: Cell Nucleus; Plant Cells; Plant Development; Plants; Plastids; Signal Transduction
PubMed: 21875565
DOI: 10.1016/B978-0-12-386037-8.00002-8