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Cell Oct 2023Gravity controls directional growth of plants, and the classical starch-statolith hypothesis proposed more than a century ago postulates that amyloplast sedimentation in...
Gravity controls directional growth of plants, and the classical starch-statolith hypothesis proposed more than a century ago postulates that amyloplast sedimentation in specialized cells initiates gravity sensing, but the molecular mechanism remains uncharacterized. The LAZY proteins are known as key regulators of gravitropism, and lazy mutants show striking gravitropic defects. Here, we report that gravistimulation by reorientation triggers mitogen-activated protein kinase (MAPK) signaling-mediated phosphorylation of Arabidopsis LAZY proteins basally polarized in root columella cells. Phosphorylation of LAZY increases its interaction with several translocons at the outer envelope membrane of chloroplasts (TOC) proteins on the surface of amyloplasts, facilitating enrichment of LAZY proteins on amyloplasts. Amyloplast sedimentation subsequently guides LAZY to relocate to the new lower side of the plasma membrane in columella cells, where LAZY induces asymmetrical auxin distribution and root differential growth. Together, this study provides a molecular interpretation for the starch-statolith hypothesis: the organelle-movement-triggered molecular polarity formation.
Topics: Arabidopsis; Arabidopsis Proteins; Gravity Sensing; Plant Roots; Plastids; Starch; Membrane Proteins
PubMed: 37741279
DOI: 10.1016/j.cell.2023.09.014 -
International Journal of Molecular... Feb 2021Eleven published articles (4 reviews, 7 research papers) are collected in the Special Issue entitled "Organelle Genetics in Plants." This selection of papers covers a...
Eleven published articles (4 reviews, 7 research papers) are collected in the Special Issue entitled "Organelle Genetics in Plants." This selection of papers covers a wide range of topics related to chloroplasts and plant mitochondria research: (i) organellar gene expression (OGE) and, more specifically, chloroplast RNA editing in soybean, mitochondria RNA editing, and intron splicing in soybean during nodulation, as well as the study of the roles of transcriptional and posttranscriptional regulation of OGE in plant adaptation to environmental stress; (ii) analysis of the nuclear integrants of mitochondrial DNA (NUMTs) or plastid DNA (NUPTs); (iii) sequencing and characterization of mitochondrial and chloroplast genomes; (iv) recent advances in plastid genome engineering. Here we summarize the main findings of these works, which represent the latest research on the genetics, genomics, and biotechnology of chloroplasts and mitochondria.
Topics: Crops, Agricultural; Genome, Mitochondrial; Plants; Plastids; RNA Editing
PubMed: 33672640
DOI: 10.3390/ijms22042104 -
Protoplasma Jan 2024
Topics: Plastids
PubMed: 38102506
DOI: 10.1007/s00709-023-01913-y -
Trends in Plant Science Oct 2019Protein amino (N) termini are major determinants of protein stability in the cytosol of eukaryotes and prokaryotes, conceptualized in the N-end rule pathway, lately... (Review)
Review
Protein amino (N) termini are major determinants of protein stability in the cytosol of eukaryotes and prokaryotes, conceptualized in the N-end rule pathway, lately referred to as N-degron pathways. Here we argue for the existence of N-degron pathways in plastids of apicomplexa, algae, and plants. The prokaryotic N-degron pathway depends on a caseinolytic protease (CLP) S recognin (adaptor) for the recognition and delivery of N-degron-bearing substrates to CLP chaperone-protease systems. Diversified CLP systems are found in chloroplasts and nonphotosynthetic plastids, including CLPS homologs that specifically interact with a subset of N-terminal residues and stromal proteins. Chloroplast N-terminome data show enrichment of classic stabilizing residues [Ala (A), Ser (S), Val (V), Thr (T)] and avoidance of charged and large hydrophobic residues. We outline experimental test strategies for plastid N-degron pathways.
Topics: Chloroplasts; Endopeptidase Clp; Plastids
PubMed: 31300194
DOI: 10.1016/j.tplants.2019.06.013 -
Current Opinion in Plant Biology Apr 2022The plastid (chloroplast) genome of seed plants represents an attractive target of metabolic pathway engineering by genetic transformation. Although the plastid genome... (Review)
Review
The plastid (chloroplast) genome of seed plants represents an attractive target of metabolic pathway engineering by genetic transformation. Although the plastid genome is relatively small, it can accommodate large amounts of foreign DNA that precisely integrates via homologous recombination, and is largely excluded from pollen transmission due to the maternal mode of plastid inheritance. Since the engineering of metabolic pathways often requires the expression of multiple transgenes, the possibility to conveniently stack transgenes in synthetic operons makes the transplastomic technology particularly appealing in the area of metabolic engineering. Absence of epigenetic gene silencing mechanisms from plastids and the possibility to achieve high transgene expression levels further add to the attractiveness of plastid genome transformation. This review focuses on engineering principles and available tools for the transplastomic expression of enzymes and pathways, and highlights selected recent applications in metabolic engineering.
Topics: Chloroplasts; Genetic Engineering; Metabolic Engineering; Plants, Genetically Modified; Plastids; Transgenes
PubMed: 35183927
DOI: 10.1016/j.pbi.2022.102185 -
Science (New York, N.Y.) Sep 2023Organisms have evolved under gravitational force, and many sense the direction of gravity by means of statoliths in specialized cells. In flowering plants,...
Organisms have evolved under gravitational force, and many sense the direction of gravity by means of statoliths in specialized cells. In flowering plants, starch-accumulating plastids, known as amyloplasts, act as statoliths to facilitate downstream gravitropism. The gravity-sensing mechanism has long been considered a mechanosensing process by which amyloplasts transmit forces to intracellular structures, but the molecular mechanism underlying this has not been elucidated. We show here that LAZY1-LIKE (LZY) family proteins involved in statocyte gravity signaling associate with amyloplasts and the proximal plasma membrane. This results in polar localization according to the direction of gravity. We propose a gravity-sensing mechanism by which LZY translocation to the plasma membrane signals the direction of gravity by transmitting information on the position of amyloplasts.
Topics: Humans; Cell Membrane; Cell Polarity; Gravitation; Gravitropism; Gravity Sensing; Plastids; Protein Transport; Arabidopsis Proteins; Arabidopsis
PubMed: 37561884
DOI: 10.1126/science.adh9978 -
Plant & Cell Physiology May 2024
Topics: Mitochondria; Plastids; Plants
PubMed: 38590035
DOI: 10.1093/pcp/pcae036 -
The New Phytologist Sep 2021Endosymbiosis is a relationship between two organisms wherein one cell resides inside the other. This affiliation, when stable and beneficial for the 'host' cell, can... (Review)
Review
Endosymbiosis is a relationship between two organisms wherein one cell resides inside the other. This affiliation, when stable and beneficial for the 'host' cell, can result in massive genetic innovation with the foremost examples being the evolution of eukaryotic organelles, the mitochondria and plastids. Despite its critical evolutionary role, there is limited knowledge about how endosymbiosis is initially established and how host-endosymbiont biology is integrated. Here, we explore this issue, using as our model the rhizarian amoeba Paulinella, which represents an independent case of primary plastid origin that occurred c. 120 million yr ago. We propose the 'chassis and engine' model that provides a theoretical framework for understanding primary plastid endosymbiosis, potentially explaining why it is so rare.
Topics: Amoeba; Biological Evolution; Eukaryota; Phylogeny; Plastids; Symbiosis
PubMed: 34018613
DOI: 10.1111/nph.17478 -
Genome Biology and Evolution Jul 2020The origin of plastids (chloroplasts) by endosymbiosis stands as one of the most important events in the history of eukaryotic life. The genetic, biochemical, and cell... (Review)
Review
The origin of plastids (chloroplasts) by endosymbiosis stands as one of the most important events in the history of eukaryotic life. The genetic, biochemical, and cell biological integration of a cyanobacterial endosymbiont into a heterotrophic host eukaryote approximately a billion years ago paved the way for the evolution of diverse algal groups in a wide range of aquatic and, eventually, terrestrial environments. Plastids have on multiple occasions also moved horizontally from eukaryote to eukaryote by secondary and tertiary endosymbiotic events. The overall picture of extant photosynthetic diversity can best be described as "patchy": Plastid-bearing lineages are spread far and wide across the eukaryotic tree of life, nested within heterotrophic groups. The algae do not constitute a monophyletic entity, and understanding how, and how often, plastids have moved from branch to branch on the eukaryotic tree remains one of the most fundamental unsolved problems in the field of cell evolution. In this review, we provide an overview of recent advances in our understanding of the origin and spread of plastids from the perspective of comparative genomics. Recent years have seen significant improvements in genomic sampling from photosynthetic and nonphotosynthetic lineages, both of which have added important pieces to the puzzle of plastid evolution. Comparative genomics has also allowed us to better understand how endosymbionts become organelles.
Topics: Amoeba; Biological Evolution; Chromatophores; Diatoms; Genomics; Photosynthesis; Plastids; Symbiosis
PubMed: 32402068
DOI: 10.1093/gbe/evaa096 -
Current Opinion in Plant Biology Feb 2022Mechanical forces were arguably among the first stimuli to be perceived by cells, and they continue to shape the evolution of all organisms. Great strides have been made... (Review)
Review
Mechanical forces were arguably among the first stimuli to be perceived by cells, and they continue to shape the evolution of all organisms. Great strides have been made in recent years in the field of plant cell and molecular mechanobiology, in part owing to focused efforts on key model systems. Here, we propose to enrich such work through evolutionary mechanobiology, or 'evo-mechano', and describe three major themes that could drive research in this area. We use plastid evo-mechano as a case study, describing how plastids from different lineages perceive their mechanical environments, how their mechanical properties vary across lineages, and their distinct roles in graviperception. Finally, we argue that future research into the biomechanical properties and mechanobiological signaling mechanisms that have been elaborated by green species over the past 1.5 billion years will help us understand both the universal and the unique adaptations of plants to their physical environment.
Topics: Biophysics; Models, Biological; Plant Cells; Plants; Plastids
PubMed: 34628340
DOI: 10.1016/j.pbi.2021.102112