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Frontiers in Plant Science 2023Abiotic stress has a significant impact on plant growth and development. It causes changes in the subcellular organelles, which, due to their stress sensitivity, can be... (Review)
Review
Abiotic stress has a significant impact on plant growth and development. It causes changes in the subcellular organelles, which, due to their stress sensitivity, can be affected. Cellular components involved in the abiotic stress response include dehydrins, widely distributed proteins forming a class II of late embryogenesis abundant protein family with characteristic properties including the presence of evolutionarily conserved sequence motifs (including lysine-rich K-segment, N-terminal Y-segment, and often phosphorylated S motif) and high hydrophilicity and disordered structure in the unbound state. Selected dehydrins and few poorly characterized dehydrin-like proteins participate in cellular stress acclimation and are also shown to interact with organelles. Through their functioning in stabilizing biological membranes and binding reactive oxygen species, dehydrins and dehydrin-like proteins contribute to the protection of fragile organellar structures under adverse conditions. Our review characterizes the participation of plant dehydrins and dehydrin-like proteins (including some organellar proteins) in plant acclimation to diverse abiotic stress conditions and summarizes recent updates on their structure (the identification of dehydrin less conserved motifs), classification (new proposed subclasses), tissue- and developmentally specific accumulation, and key cellular activities (including organellar protection under stress acclimation). Recent findings on the subcellular localization (with emphasis on the mitochondria and plastids) and prospective applications of dehydrins and dehydrin-like proteins in functional studies to alleviate the harmful stress consequences by means of plant genetic engineering and a genome editing strategy are also discussed.
PubMed: 37484455
DOI: 10.3389/fpls.2023.1213188 -
Advanced Science (Weinheim,... Sep 2023Crops must efficiently allocate their limited energy resources to survival, growth and reproduction, including balancing growth and defense. Thus, investigating the...
Crops must efficiently allocate their limited energy resources to survival, growth and reproduction, including balancing growth and defense. Thus, investigating the underlying molecular mechanism of crop under stress is crucial for breeding. Chloroplasts immunity is an important facet involving in plant resistance and growth, however, whether and how crop immunity modulated by chloroplast is influenced by epigenetic regulation remains unclear. Here, the cotton lysine 2-hydroxyisobutyrylation (Khib) and succinylation (Ksuc) modifications are firstly identified and characterized, and discover that the chloroplast proteins are hit most. Both modifications are strongly associated with plant resistance to Verticillium dahliae, reflected by Khib specifically modulating PR and salicylic acid (SA) signal pathway and the identified GhHDA15 and GhSRT1 negatively regulating Verticillium wilt (VW) resistance via removing Khib and Ksuc. Further investigation uncovers that photosystem repair protein GhPSB27 situates in the core hub of both Khib- and Ksuc-modified proteins network. The acylated GhPSB27 regulated by GhHDA15 and GhSRT1 can raise the D1 protein content, further enhancing plant biomass- and seed-yield and disease resistance via increasing photosynthesis and by-products of chloroplast-derived reactive oxygen species (cROS). Therefore, this study reveals a mechanism balancing high disease resistance and high yield through epigenetic regulation of chloroplast protein, providing a novel strategy to crop improvements.
Topics: Humans; Disease Resistance; Lysine; Epigenesis, Genetic; Plant Proteins; Photosynthesis; Chloroplasts
PubMed: 37492013
DOI: 10.1002/advs.202301803 -
Plant Physiology Aug 2023In thylakoid membranes, photosystem II (PSII) monomers from the stromal lamellae contain the subunits PsbS and Psb27 (PSIIm-S/27), while PSII monomers (PSIIm) from...
In thylakoid membranes, photosystem II (PSII) monomers from the stromal lamellae contain the subunits PsbS and Psb27 (PSIIm-S/27), while PSII monomers (PSIIm) from granal regions lack these subunits. Here, we have isolated and characterized these 2 types of PSII complexes in tobacco (Nicotiana tabacum). PSIIm-S/27 showed enhanced fluorescence, the near absence of oxygen evolution, and limited and slow electron transfer from QA to QB compared to the near-normal activities in the granal PSIIm. However, when bicarbonate was added to PSIIm-S/27, water splitting and QA to QB electron transfer rates were comparable to those in granal PSIIm. The findings suggest that the binding of PsbS and/or Psb27 inhibits forward electron transfer and lowers the binding affinity for bicarbonate. This can be rationalized in terms of the recently discovered photoprotection role played by bicarbonate binding via the redox tuning of the QA/QA•- couple, which controls the charge recombination route, and this limits chlorophyll triplet-mediated 1O2 formation. These findings suggest that PSIIm-S/27 is an intermediate in the assembly of PSII in which PsbS and/or Psb27 restrict PSII activity while in transit using a bicarbonate-mediated switch and protective mechanism.
Topics: Photosystem II Protein Complex; Bicarbonates; Thylakoids; Electron Transport; Oxidation-Reduction
PubMed: 37202365
DOI: 10.1093/plphys/kiad275 -
Cell Reports Oct 2023Clathrin-mediated vesicular formation and trafficking are responsible for molecular cargo transport and signal transduction among organelles. Our previous study shows...
Clathrin-mediated vesicular formation and trafficking are responsible for molecular cargo transport and signal transduction among organelles. Our previous study shows that CHLOROPLAST VESICULATION (CV)-containing vesicles (CVVs) are generated from chloroplasts for chloroplast degradation under abiotic stress. Here, we show that CV interacts with the clathrin heavy chain (CHC) and induces vesicle budding toward the cytosol from the chloroplast inner envelope membrane. In the defective mutants of CHC2 and the dynamin-encoding DRP1A, CVV budding and releasing from chloroplast are impeded. The mutations of CHC2 inhibit CV-induced chloroplast degradation and hypersensitivity to water stress. Moreover, CV-CHC2 interaction is impaired by the oxidized GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPC). GAPC1 overexpression suppresses CV-mediated chloroplast degradation and hypersensitivity to water stress, while CV silencing alleviates the hypersensitivity of the gapc1gapc2 plant to water stress. Together, our work identifies a pathway of clathrin-assisted CVV budding outward from chloroplast, which is involved in chloroplast degradation and stress response.
Topics: Humans; Arabidopsis Proteins; Arabidopsis; Dehydration; Chloroplasts; Clathrin; Endocytosis
PubMed: 37792531
DOI: 10.1016/j.celrep.2023.113208 -
Plant Physiology and Biochemistry : PPB Jun 2024In land plants plastid type differentiation occurs concomitantly with cellular differentiation and the transition from one type to another is under developmental and...
In land plants plastid type differentiation occurs concomitantly with cellular differentiation and the transition from one type to another is under developmental and environmental control. Plastid dynamism is based on a bilateral communication between plastids and nucleus through anterograde and retrograde signaling. Signaling occurs through the interaction with specific phytohormones (abscisic acid, strigolactones, jasmonates, gibberellins, brassinosteroids, ethylene, salicylic acid, cytokinin and auxin). The review is focused on the modulation of plastid capabilities at both transcriptional and post-translational levels at the crossroad between development and stress, with a particular attention to the chloroplast, because the most studied plastid type. The role of plastid-encoded and nuclear-encoded proteins for plastid development and stress responses, and the changes of plastid fate through the activity of stromules and plastoglobules, are discussed. Examples of plastid dynamism in response to soil stress agents (salinity, lead, cadmium, arsenic, and chromium) are described. Albinism and root greening are described based on the modulation activities of auxin and cytokinin. The physiological and functional responses of the sensory epidermal and vascular plastids to abiotic and biotic stresses along with their specific roles in stress sensing are described together with their potential modulation of retrograde signaling pathways. Future research perspectives include an in-depth study of sensory plastids to explore their potential for establishing a transgenerational memory to stress. Suggestions about anterograde and retrograde pathways acting at interspecific level and on the lipids of plastoglobules as a novel class of plastid morphogenic agents are provided.
PubMed: 38861821
DOI: 10.1016/j.plaphy.2024.108813 -
Molecular Cell Mar 2024Chloroplasts contain a dedicated genome that encodes subunits of the photosynthesis machinery. Transcription of photosynthesis genes is predominantly carried out by a...
Chloroplasts contain a dedicated genome that encodes subunits of the photosynthesis machinery. Transcription of photosynthesis genes is predominantly carried out by a plastid-encoded RNA polymerase (PEP), a nearly 1 MDa complex composed of core subunits with homology to eubacterial RNA polymerases (RNAPs) and at least 12 additional chloroplast-specific PEP-associated proteins (PAPs). However, the architecture of this complex and the functions of the PAPs remain unknown. Here, we report the cryo-EM structure of a 19-subunit PEP complex from Sinapis alba (white mustard). The structure reveals that the PEP core resembles prokaryotic and nuclear RNAPs but contains chloroplast-specific features that mediate interactions with the PAPs. The PAPs are unrelated to known transcription factors and arrange around the core in a unique fashion. Their structures suggest potential functions during transcription in the chemical environment of chloroplasts. These results reveal structural insights into chloroplast transcription and provide a framework for understanding photosynthesis gene expression.
Topics: RNA, Chloroplast; DNA-Directed RNA Polymerases; Chloroplasts; Plastids; Gene Expression Regulation, Plant; Transcription, Genetic
PubMed: 38428434
DOI: 10.1016/j.molcel.2024.02.003 -
The Plant Pathology Journal Apr 2024Land plants produce glucose (C6H12O6) through photosynthesis by utilizing carbon dioxide (CO2), water (H2O), and light energy. Glucose can be stored in various... (Review)
Review
Land plants produce glucose (C6H12O6) through photosynthesis by utilizing carbon dioxide (CO2), water (H2O), and light energy. Glucose can be stored in various polysaccharide forms for later use (e.g., sucrose in fruit, amylose in plastids), used to create cellulose, the primary structural component of cell walls, and immediately metabolized to generate cellular energy, adenosine triphosphate, through a series of respiratory pathways including glycolysis, the tricarboxylic acid cycle, and oxidative phosphorylation. Additionally, plants must metabolize glucose into amino acids, nucleotides, and various plant hormones, which are crucial for regulating many aspects of plant physiology. This review will summarize the biosynthesis of different plant hormones, such as auxin, salicylic acid, gibberellins, cytokinins, ethylene, and abscisic acid, in relation to glucose metabolism.
PubMed: 38606440
DOI: 10.5423/PPJ.RW.01.2024.0006 -
Plant Physiology Apr 2024The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is... (Review)
Review
The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is remarkable how many organisms use the reaction sequence described 70 yrs ago, which is now known as the Calvin-Benson cycle or variants such as the Calvin-Benson-Bassham cycle or Benson-Calvin cycle. However, once the carbon has entered the Calvin-Benson cycle and is converted to a 3-carbon sugar, it has many potential fates. This review will examine the last stages of photosynthetic metabolism in leaves. In land plants, this process mostly involves the production of sucrose provided by an endosymbiont (the chloroplast) to its host for use and transport to the rest of the plant. Photosynthetic metabolism also usually involves the synthesis of starch, which helps maintain respiration in the dark and enables the symbiont to supply sugars during both the day and night. Other end products made in the chloroplast are closely tied to photosynthetic CO2 assimilation. These include serine from photorespiration and various amino acids, fatty acids, isoprenoids, and shikimate pathway products. I also describe 2 pathways that can short circuit parts of the Calvin-Benson cycle. These final processes of photosynthetic metabolism play many important roles in plants.
Topics: Photosynthesis; Carbon; Chloroplasts; Plant Leaves; Plants
PubMed: 38163636
DOI: 10.1093/plphys/kiad601 -
Cell Dec 2023Photosynthesis is central to food production and the Earth's biogeochemistry, yet the molecular basis for its regulation remains poorly understood. Here, using...
Photosynthesis is central to food production and the Earth's biogeochemistry, yet the molecular basis for its regulation remains poorly understood. Here, using high-throughput genetics in the model eukaryotic alga Chlamydomonas reinhardtii, we identify with high confidence (false discovery rate [FDR] < 0.11) 70 poorly characterized genes required for photosynthesis. We then enable the functional characterization of these genes by providing a resource of proteomes of mutant strains, each lacking one of these genes. The data allow assignment of 34 genes to the biogenesis or regulation of one or more specific photosynthetic complexes. Further analysis uncovers biogenesis/regulatory roles for at least seven proteins, including five photosystem I mRNA maturation factors, the chloroplast translation factor MTF1, and the master regulator PMR1, which regulates chloroplast genes via nuclear-expressed factors. Our work provides a rich resource identifying regulatory and functional genes and placing them into pathways, thereby opening the door to a system-level understanding of photosynthesis.
Topics: Chlamydomonas reinhardtii; Chloroplasts; Photosynthesis; Gene Expression Regulation; Proteins; Mutation; Ribosomes; RNA, Messenger
PubMed: 38065083
DOI: 10.1016/j.cell.2023.11.007 -
Current Opinion in Plant Biology Aug 2023Among the eight forms of vitamin E, only tocopherols are essential compounds that are distributed throughout the entire plant kingdom, with α-tocopherol being the most... (Review)
Review
Among the eight forms of vitamin E, only tocopherols are essential compounds that are distributed throughout the entire plant kingdom, with α-tocopherol being the most predominant form in photosynthetic tissues. At the cellular level, α-tocopherol is of special relevance inside the chloroplast, where it eliminates singlet oxygen and modulates lipid peroxidation. This is of utmost relevance since tocopherols are the only antioxidants that counteract lipid peroxidation. Moreover, at the whole-plant level, α-tocopherol appears to modulate several physiological processes from germination to senescence. The antioxidant role of α-tocopherol at the cellular level can have profound effects at the whole-plant level, including the modulation of physiological processes that are apparently not related to redox processes and could be considered non-antioxidant functions. Here, we discuss whether non-antioxidant functions of α-tocopherol at the whole-plant level are mediated by its antioxidant role in chloroplasts and the regulation of redox processes at the cellular level.
Topics: Antioxidants; alpha-Tocopherol; Vitamin E; Tocopherols; Chloroplasts
PubMed: 37311290
DOI: 10.1016/j.pbi.2023.102400