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Biochimica Et Biophysica Acta. Gene... Mar 2021The extensive processing and protein-assisted stabilization of transcripts have been taken as evidence for a viewpoint that the control of gene expression had shifted... (Review)
Review
The extensive processing and protein-assisted stabilization of transcripts have been taken as evidence for a viewpoint that the control of gene expression had shifted entirely in evolution from transcriptional in the bacterial endosymbiont to posttranscriptional in the plastid. This suggestion is however at odds with many observations on plastid gene transcription. Chloroplasts of flowering plants and mosses contain two or more RNA polymerases with distinct promoter preference and division of labor for the coordinated synthesis of plastid RNAs. Plant and algal plastids further possess multiple nonredundant sigma factors that function as transcription initiation factors. The controlled accumulation of plastid sigma factors and modification of their activity by sigma-binding proteins and phosphorylation constitute additional transcriptional regulatory strategies. Plant and algal plastids also contain dedicated one- or two-component transcriptional regulators. Transcription initiation thus continues to form a critical control point at which varied developmental and environmental signals intersect with plastid gene expression.
Topics: DNA-Directed RNA Polymerases; Gene Expression Regulation, Plant; Plant Proteins; Plastids; Transcription Initiation, Genetic
PubMed: 33561560
DOI: 10.1016/j.bbagrm.2021.194689 -
Journal of Experimental Botany Nov 2016Plastid transformation has emerged as an alternative platform to generate transgenic plants. Attractive features of this technology include specific integration of... (Review)
Review
Plastid transformation has emerged as an alternative platform to generate transgenic plants. Attractive features of this technology include specific integration of transgenes-either individually or as operons-into the plastid genome through homologous recombination, the potential for high-level protein expression, and transgene containment because of the maternal inheritance of plastids. Several issues associated with nuclear transformation such as gene silencing, variable gene expression due to the Mendelian laws of inheritance, and epigenetic regulation have not been observed in the plastid genome. Plastid transformation has been successfully used for the production of therapeutics, vaccines, antigens, and commercial enzymes, and for engineering various agronomic traits including resistance to biotic and abiotic stresses. However, these demonstrations have usually focused on model systems such as tobacco, and the technology per se has not yet reached the market. Technical factors limiting this technology include the lack of efficient protocols for the transformation of cereals, poor transgene expression in non-green plastids, a limited number of selection markers, and the lengthy procedures required to recover fully segregated plants. This article discusses the technology of transforming the plastid genome, the positive and negative features compared with nuclear transformation, and the current challenges that need to be addressed for successful commercialization.
Topics: Genetic Engineering; Plants, Genetically Modified; Plastids; Transformation, Genetic
PubMed: 27697788
DOI: 10.1093/jxb/erw360 -
Plant Biology (Stuttgart, Germany) Sep 2021Reactive oxygen species (ROS) generation within a cell is a natural process of specific subcellular components involved in redox reactions. Within a plant cell,... (Review)
Review
Reactive oxygen species (ROS) generation within a cell is a natural process of specific subcellular components involved in redox reactions. Within a plant cell, chloroplasts are one of the major sources of ROS generation. Plastid-generated ROS molecules include singlet oxygen ( O ), superoxide radical (O ), hydroxyl radical (OH ) and hydrogen peroxide (H O ), which are produced mainly during photochemical reactions of photosynthesis and chlorophyll biosynthetic process. Under normal growth and developmental, generated ROS molecules act as a secondary messenger controlling several metabolic reactions; however, perturbed environmental conditions lead to multi-fold amplification of cellular ROS that eventually kill the target cell. To maintain homeostasis between production and scavenging of ROS, the cell has instituted several enzymatic and non-enzymatic antioxidant machineries to maintain ROS at a physiological level. Among chloroplastic ROS molecules, excess generation of singlet oxygen ( O ) is highly deleterious to the cell metabolic functions and survival. Interestingly, within cellular antioxidant machinery, enzymes involved in detoxification of O are lacking. Recent studies suggest that under optimal concentrations, O acts as a signalling molecule and drives the cell to either the acclimation pathway or regulated cell death (RCD). Stress-induced RCD is a survival mechanism for the whole plant, while the involvement of chloroplasts and chloroplast-localized molecules that execute RCD are not well understood. In this review, we advocate for participation of chloroplasts-generated O in signalling and RCD in plants.
Topics: Chloroplasts; Plastids; Reactive Oxygen Species; Regulated Cell Death; Singlet Oxygen
PubMed: 33768665
DOI: 10.1111/plb.13260 -
Photosynthesis Research Dec 2018The plastid proteome changes according to developmental stages. Accruing evidence shows that, in addition to transcriptional and translational controls, preprotein... (Review)
Review
The plastid proteome changes according to developmental stages. Accruing evidence shows that, in addition to transcriptional and translational controls, preprotein import into plastids is also part of the process regulating plastid proteomes. Different preproteins have distinct preferences for plastids of different tissues. Preproteins are also divided into at least three age-selective groups based on their import preference for chloroplasts of different ages. Both tissue and age selectivity are determined by the transit peptide of each preprotein, and a transit-peptide motif for older-chloroplast preference has been identified. Future challenges lie in identifying other motifs for tissue and age selectivity, as well as in identifying the receptor components that decipher these motifs. Developmental regulation also suggests that caution should be exercised when comparing protein import data generated with plastids isolated from different tissues or with chloroplasts isolated from plants of different ages.
Topics: Chloroplast Proteins; Organ Specificity; Plant Development; Plastids; Protein Sorting Signals; Protein Transport
PubMed: 29943361
DOI: 10.1007/s11120-018-0546-4 -
PLoS Pathogens Jun 2019
Review
Topics: Apicomplexa; Intracellular Membranes; Plastids
PubMed: 31194842
DOI: 10.1371/journal.ppat.1007661 -
Biomolecules Nov 2021Plastids are membrane-bound organelles that bestow phototrophic abilities to eukaryotes [...].
Plastids are membrane-bound organelles that bestow phototrophic abilities to eukaryotes [...].
Topics: Biological Evolution; Dinoflagellida; Phylogeny; Plastids; Symbiosis
PubMed: 34827692
DOI: 10.3390/biom11111694 -
Methods in Molecular Biology (Clifton,... 2021The plastid genome (plastome ) has proved a valuable source of data for evaluating evolutionary relationships among angiosperms. Through basic and applied approaches,...
The plastid genome (plastome ) has proved a valuable source of data for evaluating evolutionary relationships among angiosperms. Through basic and applied approaches, plastid transformation technology offers the potential to understand and improve plant productivity, providing food, fiber, energy, and medicines to meet the needs of a burgeoning global population. The growing genomic resources available to both phylogenetic and biotechnological investigations is allowing novel insights and expanding the scope of plastome research to encompass new species. In this chapter, we present an overview of some of the seminal and contemporary research that has contributed to our current understanding of plastome evolution and attempt to highlight the relationship between evolutionary mechanisms and the tools of plastid genetic engineering.
Topics: Evolution, Molecular; Genes, Plant; Genetic Engineering; Genetic Variation; Genome, Plastid; Magnoliopsida; Phylogeny; Plastids
PubMed: 34028761
DOI: 10.1007/978-1-0716-1472-3_1 -
Methods in Molecular Biology (Clifton,... 2018A substantial portion of eukaryote diversity consists of algae with complex plastids, i.e., plastids originating from eukaryote-to-eukaryote endosymbioses. These... (Review)
Review
A substantial portion of eukaryote diversity consists of algae with complex plastids, i.e., plastids originating from eukaryote-to-eukaryote endosymbioses. These plastids are characteristic by a deviating number of envelope membranes (higher than two), and sometimes a remnant nucleus of the endosymbiont alga, termed the nucleomorph, is present. Complex plastid-bearing algae are therefore much like living matryoshka dolls, eukaryotes within eukaryotes. In comparison, primary plastids of Archaeplastida (plants, green algae, red algae, and glaucophytes) arose upon a single endosymbiosis event with a cyanobacterium and are surrounded by two membranes. Complex plastids were acquired several times by unrelated groups nested within eukaryotic heterotrophs, suggesting complex plastids are somewhat easier to obtain than primary plastids. This is consistent with the existence of higher-order and serial endosymbioses, i.e., engulfment of complex plastid-bearing algae by (tertiary) eukaryotic hosts and functional plastid replacements, respectively. Plastid endosymbiosis is typical by a massive transfer of genetic material from the endosymbiont to the host nucleus and metabolic rearrangements related to the trophic switch to phototrophy; this is necessary to establish metabolic integration of the plastid and control over its division. Although photosynthesis is the main advantage of plastid acquisition, algae that lost photosynthesis often maintain complex plastids, suggesting their roles beyond photosynthesis. This chapter summarizes basic knowledge on acquisition and functions of complex plastid.
Topics: Biological Evolution; Eukaryota; Photosynthesis; Plastids; Symbiosis
PubMed: 29987712
DOI: 10.1007/978-1-4939-8654-5_2 -
Current Opinion in Plant Biology Apr 2018Plastids represent the only subcellular compartment where aromatic amino acid precursors for lignin can be synthesized during secondary growth in vascular plants.... (Review)
Review
Plastids represent the only subcellular compartment where aromatic amino acid precursors for lignin can be synthesized during secondary growth in vascular plants. Despite this, aside from a general shared understanding that plastid-localized metabolism occurs during secondary growth, virtually no research has been performed on understanding their biology. Of particular importance will be insight into their ontogeny, morphology and ultrastructure, and (given the complex cytonuclear communication required) their nuclear-encoded and organellar-encoded regulation. Updating and integrating this knowledge will contribute to our fundamental understanding of a ubiquitous developmental process in vascular plants, and a major terrestrial carbon sink, as well as carbon-related plant biotechnology. Given available evidence, we propose a new name for a distinct plastid derivative-the 'xyloplast', is required.
Topics: Gene Expression Regulation, Plant; Lignin; Plant Proteins; Plants; Plastids
PubMed: 29459221
DOI: 10.1016/j.pbi.2018.01.011 -
Biochemistry. Biokhimiia Jun 2017This review presents current views on the plastid genomes of higher plants and summarizes data on the size, structural organization, gene content, and other features of... (Review)
Review
This review presents current views on the plastid genomes of higher plants and summarizes data on the size, structural organization, gene content, and other features of plastid DNAs. Special emphasis is placed on the properties of organization of land plant plastid genomes (nucleoids) that distinguish them from bacterial genomes. The prospects of genetic engineering of chloroplast genomes are discussed.
Topics: DNA, Plant; Genetic Engineering; Genome, Plastid; Plastids
PubMed: 28601077
DOI: 10.1134/S0006297917060049