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The New Phytologist Jun 2021Plants are able to adjust phenotype in response to changes in the environment. This system depends on an internal capacity to sense environmental conditions and to... (Review)
Review
Plants are able to adjust phenotype in response to changes in the environment. This system depends on an internal capacity to sense environmental conditions and to process this information to plant response. Recent studies have pointed to mitochondria and plastids as important environmental sensors, capable of perceiving stressful conditions and triggering gene expression, epigenomic, metabolic and phytohormone changes in the plant. These processes involve integrated gene networks that ultimately modulate the energy balance between growth and plant defense. This review attempts to link several unusual recent findings into a comprehensive hypothesis for the regulation of plant phenotypic plasticity.
Topics: Gene Expression Regulation, Plant; Mitochondria; Phenotype; Plants; Plastids
PubMed: 33704791
DOI: 10.1111/nph.17333 -
ELife Apr 2015The enzyme that catalyses the last step in the synthesis of ascorbate has been repeatedly lost and replaced during the evolution of the different kingdoms of eukaryotes.
The enzyme that catalyses the last step in the synthesis of ascorbate has been repeatedly lost and replaced during the evolution of the different kingdoms of eukaryotes.
Topics: Animals; Ascorbic Acid; Biological Evolution; Biosynthetic Pathways; Eukaryota; Photosynthesis; Plastids
PubMed: 25872909
DOI: 10.7554/eLife.07527 -
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 -
Journal of Plant Research Sep 2018Chloroplasts (plastids) and mitochondria evolved from endosymbiotic bacteria. These organelles perform vital functions in photosynthetic eukaryotes, such as harvesting... (Review)
Review
Chloroplasts (plastids) and mitochondria evolved from endosymbiotic bacteria. These organelles perform vital functions in photosynthetic eukaryotes, such as harvesting and converting energy for use in biological processes. Consistent with their evolutionary origins, plastids and mitochondria proliferate by the binary fission of pre-existing organelles. Here, I review the structures and functions of the supramolecular machineries driving plastid and mitochondrial division, which were discovered and first studied in the primitive red alga Cyanidioschyzon merolae. In the past decade, intact division machineries have been isolated from plastids and mitochondria and examined to investigate their underlying structure and molecular mechanisms. A series of studies has elucidated how these division machineries assemble and transform during the fission of these organelles, and which of the component proteins generate the motive force for their contraction. Plastid- and mitochondrial-division machineries have important similarities in their structures and mechanisms despite sharing no component proteins, implying that these division machineries evolved in parallel. The establishment of these division machineries might have enabled the host eukaryotic ancestor to permanently retain these endosymbiotic organelles by regulating their binary fission and the equal distribution of resources to daughter cells. These findings provide key insights into the establishment of endosymbiotic organelles and have opened new avenues of research into their evolution and mechanisms of proliferation.
Topics: Cell Division; Chloroplasts; Mitochondria; Organelles; Plastids; Rhodophyta; Symbiosis
PubMed: 29948488
DOI: 10.1007/s10265-018-1050-9 -
Journal of Experimental Botany Nov 2022Plant seeds do not contain differentiated chloroplasts. Upon germination, the seedlings thus need to gain photoautotrophy before storage energies are depleted. This... (Review)
Review
Plant seeds do not contain differentiated chloroplasts. Upon germination, the seedlings thus need to gain photoautotrophy before storage energies are depleted. This requires the coordinated expression of photosynthesis genes encoded in nuclear and plastid genomes. Chloroplast biogenesis needs to be additionally coordinated with the light regulation network that controls seedling development. This coordination is achieved by nucleus to plastid signals called anterograde and plastid to nucleus signals termed retrograde. Retrograde signals sent from plastids during initial chloroplast biogenesis are also called biogenic signals. They have been recognized as highly important for proper chloroplast biogenesis and for seedling development. The molecular nature, transport, targets, and signalling function of biogenic signals are, however, under debate. Several studies disproved the involvement of a number of key components that were at the base of initial models of retrograde signalling. New models now propose major roles for a functional feedback between plastid and cytosolic protein homeostasis in signalling plastid dysfunction as well as the action of dually localized nucleo-plastidic proteins that coordinate chloroplast biogenesis with light-dependent control of seedling development. This review provides a survey of the developments in this research field, summarizes the unsolved questions, highlights several recent advances, and discusses potential new working modes.
Topics: Plastids; Chloroplasts; Genome, Plastid; Chloroplast Proteins; Photosynthesis
PubMed: 36002302
DOI: 10.1093/jxb/erac344 -
Protoplasma Jul 2020
Topics: Evolution, Molecular; Humans; Plastids
PubMed: 32572583
DOI: 10.1007/s00709-020-01526-9 -
International Journal of Molecular... Nov 2021The polypeptides encoded by the chloroplast genes and some nuclear genes form the thylakoid NADH dehydrogenase (Ndh) complex, homologous to the mitochondrial complex I.... (Review)
Review
The polypeptides encoded by the chloroplast genes and some nuclear genes form the thylakoid NADH dehydrogenase (Ndh) complex, homologous to the mitochondrial complex I. Except for Charophyceae (algae related to higher plants) and a few Prasinophyceae, all eukaryotic algae lack genes. Among vascular plants, the genes are absent in epiphytic and in some species scattered among different genera, families, and orders. The recent identification of many plants lacking plastid genes allows comparison on phylogenetic trees and functional investigations of the genes. The genes protect Angiosperms under various terrestrial stresses, maintaining efficient photosynthesis. On the edge of dispensability, genes provide a test for the natural selection of photosynthesis-related genes in evolution. Variable evolutionary environments place Angiosperms without genes at risk of extinction and, probably, most extant ones may have lost genes recently. Therefore, they are evolutionary endpoints in phylogenetic trees. The low number of sequenced plastid DNA and the long lifespan of some Gymnosperms lacking genes challenge models about the role of genes protecting against stress and promoting leaf senescence. Additional DNA sequencing in Gymnosperms and investigations into the molecular mechanisms of their response to stress will provide a unified model of the evolutionary and functional consequences of the lack of genes.
Topics: Charophyceae; Chloroplasts; Genes, Chloroplast; NADH Dehydrogenase; Photosynthesis; Plant Senescence; Plastids; Thylakoids
PubMed: 34830386
DOI: 10.3390/ijms222212505 -
Molecular Plant Jun 2019Mitochondria and plastids form dynamic, evolving populations physically embedded in the fluctuating environment of the plant cell. Their evolutionary heritage has shaped... (Review)
Review
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.
Topics: Cell Nucleus; Chloroplasts; Mitochondria; Organelles; Plant Cells; Plastids
PubMed: 30445187
DOI: 10.1016/j.molp.2018.11.002 -
Current Opinion in Plant Biology Oct 2021Chloroplasts and mitochondria evolved from free-living prokaryotic organisms that entered the eukaryotic cell through endosymbiosis. The gradual conversion from... (Review)
Review
Chloroplasts and mitochondria evolved from free-living prokaryotic organisms that entered the eukaryotic cell through endosymbiosis. The gradual conversion from endosymbiont to organelle during the course of evolution was accompanied by the development of a communication system between the host and the endosymbiont, referred to as retrograde signaling or organelle-to-nucleus signaling. In higher plants, plastid-to-nucleus signaling involves multiple signaling pathways necessary to coordinate plastid function and cellular responses to developmental and environmental stimuli. Phylogenetic reconstructions using sequence information from evolutionarily diverse photosynthetic eukaryotes have begun to provide information about how retrograde signaling pathways were adopted and modified in different lineages over time. A tight communication system was likely a major facilitator of plants conquest of the land because it would have enabled the algal ancestors of land plants to better allocate their cellular resources in response to high light and desiccation, the major stressor for streptophyte algae in a terrestrial habitat. In this review, we aim to give an evolutionary perspective on plastid-to-nucleus signaling.
Topics: Biological Evolution; Eukaryota; Photosynthesis; Phylogeny; Plastids; Symbiosis
PubMed: 34390927
DOI: 10.1016/j.pbi.2021.102093 -
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