-
Current Biology : CB Jan 2009A comprehensive understanding of the origin and spread of plastids remains an important yet elusive goal in the field of eukaryotic evolution. Combined with the... (Review)
Review
A comprehensive understanding of the origin and spread of plastids remains an important yet elusive goal in the field of eukaryotic evolution. Combined with the discovery of new photosynthetic and non-photosynthetic protist lineages, the results of recent taxonomically broad phylogenomic studies suggest that a re-shuffling of higher-level eukaryote systematics is in order. Consequently, new models of plastid evolution involving ancient secondary and tertiary endosymbioses are needed to explain the full spectrum of photosynthetic eukaryotes.
Topics: Animals; Biological Evolution; Cyanobacteria; Eukaryotic Cells; Gene Transfer, Horizontal; Photosynthesis; Phylogeny; Plastids; Symbiosis
PubMed: 19174147
DOI: 10.1016/j.cub.2008.11.067 -
Plant Physiology Mar 2019Building on recombinant DNA technology, leaps in synthesis, assembly, and analysis of DNA have revolutionized genetics and molecular biology over the past two decades... (Review)
Review
Building on recombinant DNA technology, leaps in synthesis, assembly, and analysis of DNA have revolutionized genetics and molecular biology over the past two decades (Kosuri and Church, 2014). These technological advances have accelerated the emergence of synthetic biology as a new discipline (Cameron et al., 2014). Synthetic biology is characterized by efforts targeted at the modification of existing and the design of novel biological systems based on principles adopted from information technology and engineering (Andrianantoandro et al., 2006; Khalil and Collins, 2010). As in more traditional engineering disciplines such as mechanical, electrical and civil engineering, synthetic biologists utilize abstraction, decoupling and standardization to make the design of biological systems more efficient and scalable. To facilitate the management of complexity, synthetic biology relies on an abstraction hierarchy composed of multiple levels (Endy, 2005): DNA as genetic material, "parts" as elements of DNA encoding basic biological functions (e.g. promoter, ribosome-binding site, terminator sequence), "devices" as any combination of parts implementing a human-defined function, and "systems" as any combination of devices fulfilling a predefined purpose. Parts are designated to perform predictable and modular functions in the context of higher-level devices or systems, which are successively refined through a cycle of designing, building, and testing.
Topics: Genetic Engineering; Genome, Chloroplast; Plastids; Synthetic Biology
PubMed: 30181342
DOI: 10.1104/pp.18.00767 -
Molecular Ecology Resources Aug 2023Although plastid genome (plastome) structure is highly conserved across most seed plants, investigations during the past two decades have revealed several disparately...
Although plastid genome (plastome) structure is highly conserved across most seed plants, investigations during the past two decades have revealed several disparately related lineages that experienced substantial rearrangements. Most plastomes contain a large inverted repeat and two single-copy regions, and a few dispersed repeats; however, the plastomes of some taxa harbour long repeat sequences (>300 bp). These long repeats make it challenging to assemble complete plastomes using short-read data, leading to misassemblies and consensus sequences with spurious rearrangements. Single-molecule, long-read sequencing has the potential to overcome these challenges, yet there is no consensus on the most effective method for accurately assembling plastomes using long-read data. We generated a pipeline, plastid Genome Assembly Using Long-read data (ptGAUL), to address the problem of plastome assembly using long-read data from Oxford Nanopore Technologies (ONT) or Pacific Biosciences platforms. We demonstrated the efficacy of the ptGAUL pipeline using 16 published long-read data sets. We showed that ptGAUL quickly produces accurate and unbiased assemblies using only ~50× coverage of plastome data. Additionally, we deployed ptGAUL to assemble four new Juncus (Juncaceae) plastomes using ONT long reads. Our results revealed many long repeats and rearrangements in Juncus plastomes compared with basal lineages of Poales. The ptGAUL pipeline is available on GitHub: https://github.com/Bean061/ptgaul.
Topics: Genome, Plastid; Repetitive Sequences, Nucleic Acid; Gene Rearrangement; Plastids; High-Throughput Nucleotide Sequencing; Sequence Analysis, DNA
PubMed: 36939021
DOI: 10.1111/1755-0998.13787 -
The EMBO Journal Nov 2020The initial greening of angiosperms involves light activation of photoreceptors that trigger photomorphogenesis, followed by the development of chloroplasts. In these...
The initial greening of angiosperms involves light activation of photoreceptors that trigger photomorphogenesis, followed by the development of chloroplasts. In these semi-autonomous organelles, construction of the photosynthetic apparatus depends on the coordination of nuclear and plastid gene expression. Here, we show that the expression of PAP8, an essential subunit of the plastid-encoded RNA polymerase (PEP) in Arabidopsis thaliana, is under the control of a regulatory element recognized by the photomorphogenic factor HY5. PAP8 protein is localized and active in both plastids and the nucleus, and particularly required for the formation of late photobodies. In the pap8 albino mutant, phytochrome-mediated signalling is altered, degradation of the chloroplast development repressors PIF1/PIF3 is disrupted, HY5 is not stabilized, and the expression of the photomorphogenesis regulator GLK1 is impaired. PAP8 translocates into plastids via its targeting pre-sequence, interacts with the PEP and eventually reaches the nucleus, where it can interact with another PEP subunit pTAC12/HMR/PAP5. Since PAP8 is required for the phytochrome B-mediated signalling cascade and the reshaping of the PEP activity, it may coordinate nuclear gene expression with PEP-driven chloroplastic gene expression during chloroplast biogenesis.
Topics: Acid Phosphatase; Arabidopsis; Arabidopsis Proteins; Cell Nucleus; Chloroplasts; DNA-Directed RNA Polymerases; Gene Expression Regulation, Plant; Light; Morphogenesis; Organelle Biogenesis; Phytochrome; Plants, Genetically Modified; Plastids; Signal Transduction; Transcription Factors; Transcription, Genetic
PubMed: 33001465
DOI: 10.15252/embj.2020104941 -
Protoplasma Oct 2012Plastid genetic engineering has come of age, becoming today an attractive alternative approach for the expression of foreign genes, as it offers several advantages over... (Review)
Review
Plastid genetic engineering has come of age, becoming today an attractive alternative approach for the expression of foreign genes, as it offers several advantages over nuclear transformants. Significant progress has been made in plastid genetic engineering in tobacco and other Solanaceae plants, through the use of improved regeneration procedures and transformation vectors with efficient promoters and untranslated regions. Many genes encoding for industrially important proteins and vaccines, as well as genes conferring important agronomic traits, have been stably integrated and expressed in the plastid genome. Despite these advances, it remains a challenge to achieve marked levels of plastid transgene expression in non-green tissues. In this review, we summarize the basic requirements of plastid genetic engineering and discuss the current status, limitations, and the potential of plastid transformation for expanding future studies relating to Solanaceae plants.
Topics: Genetic Engineering; Genetic Vectors; Plastids; Solanaceae
PubMed: 22395455
DOI: 10.1007/s00709-012-0391-9 -
Current Biology : CB Jun 2015The number and nature of endosymbioses involving red algal endosymbionts are debated. Gene phylogenies have become the most popular tool to untangle this issue, but they... (Review)
Review
The number and nature of endosymbioses involving red algal endosymbionts are debated. Gene phylogenies have become the most popular tool to untangle this issue, but they deliver conflicting results. As gene and lineage sampling has increased, so have both the number of conflicting trees and the number of suggestions in the literature for multiple tertiary, and even quaternary, symbioses that might reconcile the tree conflicts. Independent lines of evidence that can address the issue are needed. Here we summarize the mechanism and machinery of protein import into complex red plastids. The process involves protein translocation machinery, known as SELMA, that arose once in evolution, that facilitates protein import across the second outermost of the four plastid membranes, and that is always targeted specifically to that membrane, regardless of where it is encoded today. It is widely accepted that the unity of protein import across the two membranes of primary plastids is strong evidence for their single cyanobacterial origin. Similarly, the unity of SELMA-dependent protein import across the second outermost plastid membrane constitutes strong evidence for the existence of a single red secondary endosymbiotic event at the common origin of all red complex plastids. We furthermore propose that the two outer membranes of red complex plastids are derived from host endoplasmic reticulum in the initial red secondary endosymbiotic event.
Topics: Models, Biological; Phylogeny; Plastids; Protein Transport; Symbiosis
PubMed: 26079086
DOI: 10.1016/j.cub.2015.04.033 -
Biochimica Et Biophysica Acta Sep 2015The development of a repressible chloroplast gene expression system in Chlamydomonas reinhardtii has opened the door for studying the role of essential chloroplast... (Review)
Review
The development of a repressible chloroplast gene expression system in Chlamydomonas reinhardtii has opened the door for studying the role of essential chloroplast genes. This approach has been used to analyze three chloroplast genes of this sort coding for the α subunit of RNA polymerase (rpoA), a ribosomal protein (rps12) and the catalytic subunit of the ATP-dependent ClpP protease (clpP1). Depletion of the three corresponding proteins leads to growth arrest and cell death. Shutdown of chloroplast transcription and translation increases the abundance of a set of plastid transcripts that includes mainly those involved in transcription, translation and proteolysis and reveals multiple regulatory feedback loops in the chloroplast gene circuitry. Depletion of ClpP profoundly affects plastid protein homeostasis and elicits an autophagy-like response with extensive cytoplasmic vacuolization of cells. It also triggers changes in chloroplast and nuclear gene expression resulting in increased abundance of chaperones, proteases, ubiquitin-related proteins and proteins involved in lipid trafficking and thylakoid biogenesis. These features are hallmarks of an unfolded protein response in the chloroplast and raise new questions on plastid protein homeostasis and plastid signaling. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
Topics: Autophagy; Chloroplast Proteins; Gene Expression Regulation, Plant; Genes, Chloroplast; Lipid Metabolism; Plastids; Quality Control; Signal Transduction
PubMed: 25486627
DOI: 10.1016/j.bbabio.2014.11.011 -
Protoplasma Jul 2020
Topics: Evolution, Molecular; Humans; Plastids
PubMed: 32572583
DOI: 10.1007/s00709-020-01526-9 -
Current Opinion in Plant Biology Dec 2008Chloroplasts contain several thousand different proteins, of which more than 95% are encoded on nuclear genes, synthesized in the cytosol as precursor proteins, and... (Review)
Review
Chloroplasts contain several thousand different proteins, of which more than 95% are encoded on nuclear genes, synthesized in the cytosol as precursor proteins, and imported into the organelle. The major pathways for import and routing have been described; a general import apparatus in the chloroplast envelope and several ancestral translocases in the thylakoid membranes. In this update we focus on some interesting and emerging areas: the Tat translocase, which operates in parallel with the Sec system but transports folded proteins; different routes to the envelope membranes, which promises an understanding of the ways the Tic apparatus sorts transmembrane domains (TMDs) and may also uncover developmental relationships between envelope and thylakoids; and novel routes for proteins into chloroplasts including delivery from the secretory system.
Topics: Cell Compartmentation; Intracellular Membranes; Plant Proteins; Plastids; Protein Transport; Thylakoids
PubMed: 18990609
DOI: 10.1016/j.pbi.2008.10.008 -
Plant Signaling & Behavior Nov 2017Isoprenoids comprise the largest class of natural compounds and are found in all kinds of organisms. In plants, they participate in both primary and specialized...
Isoprenoids comprise the largest class of natural compounds and are found in all kinds of organisms. In plants, they participate in both primary and specialized metabolism, playing essential roles in nearly all aspects of growth and development. The enormous diversity of this family of compounds is extensively exploited for biotechnological and biomedical applications as biomaterials, biofuels or drugs. Despite their variety of structures, all isoprenoids derive from the common C precursor isopentenyl diphosphate (IPP). Plants synthesize IPP through two different metabolic pathways, the mevalonic acid (MVA) and the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathways that operate in the cytosol-RE and plastids, respectively. MEP-derived isoprenoids include important compounds for chloroplast function and as such, knock-out mutant plants affected in different steps of this pathway display important alterations in plastid structure. These alterations often lead to albino phenotypes and lethality at seedling stage. MVA knock-out mutant plants show, on the contrary, lethal phenotypes already exhibited at the gametophyte or embryo developmental stage. However, the recent characterization of conditional knock-down mutant plants of farnesyl diphosphate synthase (FPS), a central enzyme in cytosolic and mitochondrial isoprenoid biosynthesis, revealed an unexpected role of this pathway in chloroplast development and plastidial isoprenoid metabolism in post-embryonic stages. Upon FPS silencing, chloroplast structure is severely altered, together with a strong reduction in the levels of MEP pathway-derived major end products. This phenotype is associated to misregulation of genes involved in stress responses predominantly belonging to JA and Fe homeostasis pathways. Transcriptomic experiments and analysis of recent literature indicate that sterols are the cause of the observed alterations through an as yet undiscovered mechanism.
Topics: Arabidopsis; Chloroplasts; Hemiterpenes; Mevalonic Acid; Organophosphorus Compounds; Phytosterols; Plastids
PubMed: 28990832
DOI: 10.1080/15592324.2017.1387708