Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.459
Filtrar
1.
Plant Cell Rep ; 43(5): 135, 2024 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-38704787

RESUMO

KEY MESSAGE: The disruption of the SWL1 gene leads to a significant down regulation of chloroplast and secondary metabolites gene expression in Arabidopsis thaliana. And finally results in a dysfunction of chloroplast and plant growth. Although the development of the chloroplast has been a consistent focus of research, the corresponding regulatory mechanisms remain unidentified. In this study, the CRISPR/Cas9 system was used to mutate the SWL1 gene, resulting in albino cotyledons and variegated true leaf phenotype. Confocal microscopy and western blot of chloroplast protein fractions revealed that SWL1 localized in the chloroplast stroma. Electron microscopy indicated chloroplasts in the cotyledons of swl1 lack well-defined grana and internal membrane structures, and similar structures have been detected in the albino region of variegated true leaves. Transcriptome analysis revealed that down regulation of chloroplast and nuclear gene expression related to chloroplast, including light harvesting complexes, porphyrin, chlorophyll metabolism and carbon metabolism in the swl1 compared to wild-type plant. In addition, proteomic analysis combined with western blot analysis, showed that a significant decrease in chloroplast proteins of swl1. Furthermore, the expression of genes associated with secondary metabolites and growth hormones was also reduced, which may be attributed to SWL1 associated with absorption and fixation of inorganic carbon during chloroplast development. Together, the above findings provide valuable information to elucidate the exact function of SWL1 in chloroplast biogenesis and development.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Cloroplastos , Regulação da Expressão Gênica de Plantas , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/ultraestrutura , Cotilédone/genética , Cotilédone/metabolismo , Cotilédone/crescimento & desenvolvimento , Proteômica , Proteínas de Cloroplastos/metabolismo , Proteínas de Cloroplastos/genética , Biogênese de Organelas , Clorofila/metabolismo , Sistemas CRISPR-Cas
2.
Sci Rep ; 14(1): 11587, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38773239

RESUMO

Peptide deformylase can catalyse the removal of formyl groups from the N-terminal formyl methionine of the primary polypeptide chain. The peptide deformylase genes of a few herbaceous plants have been studied to some extent, but the peptide deformylase genes of woody plants have not been studied. In this study, we isolated EuPDF1B from Eucommia ulmoides Oliv. The full-length sequence of EuPDF1B is 1176 bp long with a poly-A tail and contains an open reading frame of 831 bp that encodes a protein of 276 amino acids. EuPDF1B was localized to the chloroplast. qRT‒PCR analysis revealed that this gene was expressed in almost all tissues tested but mainly in mature leaves. Moreover, the expression of EuPDF1B was enhanced by ABA, MeJA and GA and inhibited by shading treatment. The expression pattern of EuPDF1B was further confirmed in EuPDF1Bp: GUS transgenic tobacco plants. Among all the transgenic tobacco plants, EuPDF1Bp-3 showed the highest GUS histochemical staining and activity in different tissues. This difference may be related to the presence of enhancer elements in the region from - 891 bp to - 236 bp of the EuPDF1B promoter. In addition, the expression of the chloroplast gene psbA and the net photosynthetic rate, fresh weight and height of tobacco plants overexpressing EuPDF1B were greater than those of the wild-type tobacco plants, suggesting that EuPDF1B may promote the growth of transgenic tobacco plants. This is the first time that PDF and its promoter have been cloned from woody plants, laying a foundation for further analysis of the function of PDF and the regulation of its expression.


Assuntos
Amidoidrolases , Clonagem Molecular , Eucommiaceae , Regulação da Expressão Gênica de Plantas , Nicotiana , Plantas Geneticamente Modificadas , Eucommiaceae/genética , Eucommiaceae/metabolismo , Plantas Geneticamente Modificadas/genética , Amidoidrolases/genética , Amidoidrolases/metabolismo , Nicotiana/genética , Cloroplastos/genética , Cloroplastos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Filogenia , Sequência de Aminoácidos , Ciclopentanos/farmacologia , Ciclopentanos/metabolismo , Oxilipinas/farmacologia , Oxilipinas/metabolismo
3.
Plant Cell Rep ; 43(6): 141, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38743349

RESUMO

KEY MESSAGE: A GLK homologue was identified and functionally characterized in Catharanthus roseus. Silencing CrGLK with VIGS or the chloroplast retrograde signaling inducer lincomycin increased terpenoid indole alkaloid biosynthesis. Catharanthus roseus is the sole source of the chemotherapeutic terpenoid indole alkaloids (TIAs) vinblastine and vincristine. TIA pathway genes, particularly genes in the vindoline pathway, are expressed at higher levels in immature versus mature leaves, but the molecular mechanisms responsible for this developmental regulation are unknown. We investigated the role of GOLDEN2-LIKE (GLK) transcription factors in contributing to this ontogenetic regulation since GLKs are active in seedlings upon light exposure and in the leaf's early development, but their activity is repressed as leaves age and senesce. We identified a GLK homologue in C. roseus and functionally characterized its role in regulating TIA biosynthesis, with a focus on the vindoline pathway, by transiently reducing its expression through two separate methods: virus-induced gene silencing (VIGS) and application of chloroplast retrograde signaling inducers, norflurazon and lincomycin. Reducing CrGLK levels with each method reduced chlorophyll accumulation and the expression of the light harvesting complex subunit (LHCB2.2), confirming its functional homology with GLKs in other plant species. In contrast, reducing CrGLK via VIGS or lincomycin increased TIA accumulation and TIA pathway gene expression, suggesting that CrGLK may repress TIA biosynthesis. However, norflurazon had no effect on TIA gene expression, indicating that reducing CrGLK alone is not sufficient to induce TIA biosynthesis. Future work is needed to clarify the specific molecular mechanisms leading to increased TIA biosynthesis with CrGLK silencing. This is the first identification and characterization of GLK in C. roseus and the first investigation of how chloroplast retrograde signaling might regulate TIA biosynthesis.


Assuntos
Catharanthus , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Proteínas de Plantas , Alcaloides de Triptamina e Secologanina , Fatores de Transcrição , Catharanthus/genética , Catharanthus/metabolismo , Alcaloides de Triptamina e Secologanina/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Folhas de Planta/metabolismo , Folhas de Planta/genética , Cloroplastos/metabolismo
4.
BMC Plant Biol ; 24(1): 422, 2024 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-38760671

RESUMO

BACKGROUND: Salinity is one major abiotic stress affecting photosynthesis, plant growth, and development, resulting in low-input crops. Although photosynthesis underlies the substantial productivity and biomass storage of crop yield, the response of the sunflower photosynthetic machinery to salinity imposition and how H2S mitigates the salinity-induced photosynthetic injury remains largely unclear. Seed priming with 0.5 mM NaHS, as a donor of H2S, was adopted to analyze this issue under NaCl stress. Primed and nonprime seeds were established in nonsaline soil irrigated with tape water for 14 d, and then the seedlings were exposed to 150 mM NaCl for 7 d under controlled growth conditions. RESULTS: Salinity stress significantly harmed plant growth, photosynthetic parameters, the structural integrity of chloroplasts, and mesophyll cells. H2S priming improved the growth parameters, relative water content, stomatal density and aperture, photosynthetic pigments, photochemical efficiency of PSII, photosynthetic performance, soluble sugar as well as soluble protein contents while reducing proline and ABA under salinity. H2S also boosted the transcriptional level of ribulose 1,5-bisphosphate carboxylase small subunit gene (HaRBCS). Further, the transmission electron microscope showed that under H2S priming and salinity stress, mesophyll cells maintained their cell membrane integrity and integrated chloroplasts with well-developed thylakoid membranes. CONCLUSION: The results underscore the importance of H2S priming in maintaining photochemical efficiency, Rubisco activity, and preserving the chloroplast structure which participates in salinity stress adaptation, and possibly sunflower productivity under salinity imposition. This underpins retaining and minimizing the injury to the photosynthetic machinery to be a crucial trait in response of sunflower to salinity stress.


Assuntos
Helianthus , Sulfeto de Hidrogênio , Osmorregulação , Fotossíntese , Estresse Salino , Plântula , Helianthus/fisiologia , Helianthus/efeitos dos fármacos , Helianthus/crescimento & desenvolvimento , Helianthus/metabolismo , Fotossíntese/efeitos dos fármacos , Plântula/fisiologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sulfeto de Hidrogênio/metabolismo , Cloroplastos/metabolismo , Salinidade
5.
Plant Signal Behav ; 19(1): 2347783, 2024 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38699898

RESUMO

As sessile organisms, plants have evolved complex signaling mechanisms to sense stress and acclimate. This includes the use of reactive oxygen species (ROS) generated during dysfunctional photosynthesis to initiate signaling. One such ROS, singlet oxygen (1O2), can trigger retrograde signaling, chloroplast degradation, and programmed cell death. However, the signaling mechanisms are largely unknown. Several proteins (e.g. PUB4, OXI1, EX1) are proposed to play signaling roles across three Arabidopsis thaliana mutants that conditionally accumulate chloroplast 1O2 (fluorescent in blue light (flu), chlorina 1 (ch1), and plastid ferrochelatase 2 (fc2)). We previously demonstrated that these mutants reveal at least two chloroplast 1O2 signaling pathways (represented by flu and fc2/ch1). Here, we test if the 1O2-accumulating lesion mimic mutant, accelerated cell death 2 (acd2), also utilizes these pathways. The pub4-6 allele delayed lesion formation in acd2 and restored photosynthetic efficiency and biomass. Conversely, an oxi1 mutation had no measurable effect on these phenotypes. acd2 mutants were not sensitive to excess light (EL) stress, yet pub4-6 and oxi1 both conferred EL tolerance within the acd2 background, suggesting that EL-induced 1O2 signaling pathways are independent from spontaneous lesion formation. Thus, 1O2 signaling in acd2 may represent a third (partially overlapping) pathway to control cellular degradation.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Cloroplastos , Mutação , Transdução de Sinais , Oxigênio Singlete , Arabidopsis/genética , Arabidopsis/metabolismo , Oxigênio Singlete/metabolismo , Cloroplastos/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Transdução de Sinais/genética , Mutação/genética , Fotossíntese/genética
6.
Physiol Plant ; 176(2): e14273, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38566156

RESUMO

Sacoglossa sea slugs have garnered attention due to their ability to retain intracellular functional chloroplasts from algae, while degrading other algal cell components. While protective mechanisms that limit oxidative damage under excessive light are well documented in plants and algae, the photoprotective strategies employed by these photosynthetic sea slugs remain unresolved. Species within the genus Elysia are known to retain chloroplasts from various algal sources, but the extent to which the metabolic processes from the donor algae can be sustained by the sea slugs is unclear. By comparing responses to high-light conditions through kinetic analyses, molecular techniques, and biochemical assays, this study shows significant differences between two photosynthetic Elysia species with chloroplasts derived from the green alga Acetabularia acetabulum. Notably, Elysia timida displayed remarkable tolerance to high-light stress and sophisticated photoprotective mechanisms such as an active xanthophyll cycle, efficient D1 protein recycling, accumulation of heat-shock proteins and α-tocopherol. In contrast, Elysia crispata exhibited absence or limitations in these photoprotective strategies. Our findings emphasize the intricate relationship between the host animal and the stolen chloroplasts, highlighting different capacities to protect the photosynthetic organelle from oxidative damage.


Assuntos
Acetabularia , Gastrópodes , Animais , Plastídeos/metabolismo , Cloroplastos/metabolismo , Fotossíntese , Gastrópodes/metabolismo
7.
Science ; 384(6692): 217-222, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38603509

RESUMO

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or "nitroplast."


Assuntos
Cianobactérias , Haptófitas , Mitocôndrias , Fixação de Nitrogênio , Nitrogênio , Cianobactérias/genética , Cianobactérias/metabolismo , Haptófitas/microbiologia , Nitrogênio/metabolismo , Fixação de Nitrogênio/genética , Água do Mar/microbiologia , Simbiose , Mitocôndrias/metabolismo , Cloroplastos/metabolismo
8.
Plant Signal Behav ; 19(1): 2342744, 2024 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38630633

RESUMO

Chloroplast photorelocation is a vital organellar response that optimizes photosynthesis in plants amid fluctuating environmental conditions. Chloroplasts exhibit an accumulation response, in which they move toward weak light to enhance photoreception, and an avoidance response, in which they move away from strong light to avoid photodamage. Although chloroplast photorelocation has been extensively studied in model plants such as Arabidopsis thaliana, little is known about this process in the economically important crop strawberry. Here, we investigated chloroplast photorelocation in leaf mesophyll cells of wild strawberry (Fragaria vesca), a diploid relative of commercially cultivated octoploid strawberry (F. × ananassa). Microscopy observation revealed that the periclinal area of leaf mesophyll cells in F. vesca is considerably smaller than that of A. thaliana. Given this small cell size, we investigated chloroplast photorelocation in F. vesca by measuring light transmittance in leaves. Weak blue light induced the accumulation response, whereas strong blue light induced the avoidance response. Unexpectedly, strong red light also induced the accumulation response in F. vesca. These findings shed light on chloroplast photorelocation as an intracellular response, laying the foundation for enhancing photosynthesis and productivity in Fragaria.


Assuntos
Arabidopsis , Fragaria , Arabidopsis/fisiologia , Fotossíntese , Cloroplastos/metabolismo , Folhas de Planta
9.
Physiol Plant ; 176(2): e14289, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38606618

RESUMO

Albino plants display partial or complete loss of photosynthetic pigments and defective thylakoid membrane development, consequently impairing plastid function and development. These distinctive attributes render albino plants excellent models for investigating chloroplast biogenesis. Despite their potential, limited exploration has been conducted regarding the molecular alterations underlying these phenotypes, extending beyond photosynthetic metabolism. In this study, we present a novel de novo transcriptome assembly of an albino somaclonal variant of Agave angustifolia Haw., which spontaneously emerged during the micropropagation of green plantlets. Additionally, RT-qPCR analysis was employed to validate the expression of genes associated with chloroplast biogenesis, and plastome copy numbers were quantified. This research aims to gain insight into the molecular disruptions affecting chloroplast development and ascertain whether the expression of critical genes involved in plastid development and differentiation is compromised in albino tissues of A. angustifolia. Our transcriptomic findings suggest that albino Agave plastids exhibit high proliferation, activation of the protein import machinery, altered transcription directed by PEP and NEP, dysregulation of plastome expression genes, reduced expression of photosynthesis-associated nuclear genes, disruption in the tetrapyrrole and carotenoid biosynthesis pathway, alterations in the plastid ribosome, and an increased number of plastome copies, among other alterations.


Assuntos
Agave , Agave/genética , Cloroplastos/metabolismo , Fotossíntese/genética , Plastídeos/genética , Plastídeos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética
10.
Plant Sci ; 343: 112081, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38579979

RESUMO

Chlorophyll biosynthesis and breakdown, important cellular processes for photosynthesis, occur in the chloroplast. As a semi-autonomous organelle, chloroplast development is mainly regulated by nuclear-encoded chloroplast proteins and proteins encoded by itself. However, the knowledge of chloroplast development regulated by other organelles is limited. Here, we report that the nuclear-localized XAP5 CIRCADIAN TIMEKEEPER (XCT) is essential for chloroplast development in Arabidopsis. In this study, significantly decreased chlorophyll content phenotypes of cotyledons and subsequently emerging organs from shoot apical meristem were observed in xct-2. XCT is constitutively expressed in various tissues and localized in the nuclear with speckle patterns. RNA-seq analysis identified 207 differently spliced genes and 1511 differently expressed genes, in which chloroplast development-, chlorophyll metabolism- and photosynthesis-related genes were enriched. Further biochemical assays suggested that XCT was co-purified with the well-known splicing factors and transcription machinery, suggesting dual functions of XCT in gene transcription and splicing. Interestingly, we also found that the chlorophyll contents in xct-2 significantly decreased under high temperature and high light condition, indicating XCT integrates temperature and light signals to fine-tune the chlorophyll metabolism in Arabidopsis. Therefore, our results provide new insights into chloroplast development regulation by XCT, a nuclear-localized protein, at the transcriptional and post-transcriptional level.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Fotossíntese , Proteínas Nucleares/metabolismo , Clorofila/metabolismo , Regulação da Expressão Gênica de Plantas
11.
Bioresour Technol ; 401: 130757, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38688392

RESUMO

The photosynthetic autotrophic production of microalgae is limited by the effective supply of carbon and light energy, and the production efficiency is lower than the theoretical value. Represented by methanol, C1 compounds have been industrially produced by artificial photosynthesis with a solar energy efficiency over 10%, but the complexity of artificial products is weak. Here, based on a construction of chloroplast factory, green microalgae Chlamydomonas reinhardtii CC137c was modified for the bioconversion of formate for biomass production. By screening the optimal combination of chloroplast transport peptides, the cabII-1 cTP1 fusion formate dehydrogenase showed significant enhancement on the conversion of formate with a better performance in the maintenance of light reaction activity. This work provided a new way to obtain bioproducts from solar energy and CO2 with potentially higher-than-nature efficiency by the artificial-natural hybrid photosynthesis.


Assuntos
Chlamydomonas reinhardtii , Cloroplastos , Formiatos , Cloroplastos/metabolismo , Formiatos/metabolismo , Chlamydomonas reinhardtii/metabolismo , Fotossíntese , Formiato Desidrogenases/metabolismo , Biomassa
12.
Plant Physiol Biochem ; 210: 108650, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38653095

RESUMO

Plants have evolved the adaptive capacity to mitigate the negative effect of external adversities at chemical, molecular, cellular, and physiological levels. This capacity is conferred by triggering the coordinated action of internal regulatory factors, in which sugars play an essential role in the regulating chloroplast degradation and leaf senescence under various stresses. In this review, we summarize the recent findings on the senescent-associated changes in carbohydrate metabolism and its relation to chlorophyl degradation, oxidative damage, photosynthesis inhibition, programmed cell death (PCD), and sink-source relation as affected by abiotic stresses. The action of sugar signaling in regulating the initiation and progression of leaf senescence under abiotic stresses involves interactions with various plant hormones, reactive oxygen species (ROS) burst, and protein kinases. This discussion aims to elucidate the complex regulatory network and molecular mechanisms that underline sugar-induced leaf senescence in response to various abiotic stresses. The imperative role of sugar signaling in regulating plant stress responses potentially enables the production of crop plants with modified sugar metabolism. This, in turn, may facilitate the engineering of plants with improved stress responses, optimal life span and higher yield achievement.


Assuntos
Folhas de Planta , Senescência Vegetal , Transdução de Sinais , Estresse Fisiológico , Açúcares , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Açúcares/metabolismo , Metabolismo dos Carboidratos , Fotossíntese , Cloroplastos/metabolismo
13.
Chemosphere ; 358: 142125, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38670509

RESUMO

Microcystin-LR (MC-LR) is a harmful cyanotoxin that inhibits 1 and 2A serine-threonine protein phosphatases. This study examines the influence of MC-LR on chloroplast division and the underlying mechanisms and consequences in Arabidopsis. MC-LR increased the frequency of dividing chloroplasts in hypocotyls in a time range of 1-96 h. At short-term exposures to MC-LR, small-sized chloroplasts (longitudinal diameters ≤6 µm) were more sensitive to these stimulatory effects, while both small and large chloroplasts showed stimulations at long-term exposure. After 48 h, the cyanotoxin increased the frequency of small-sized chloroplasts, indicating the stimulation of division. MC-LR inhibited protein phosphatases in whole hypocotyls and isolated chloroplasts, while it did not induce oxidative stress. We show for the first time that total cellular phosphatases play important roles in chloroplast division and that particular chloroplast phosphatases may be involved in these processes. Interestingly, MC-LR has a protective effect on cyanobacterial division during methyl-viologen (MV) treatments in Synechococcus PCC6301. MC-LR production has harmful effects on ecosystems and it may have an ancient cell division regulatory role in stressed cyanobacterial cells, the evolutionary ancestors of chloroplasts. We propose that cytoplasmic (eukaryotic) factors also contribute to the relevant effects of MC-LR in plants.


Assuntos
Arabidopsis , Cloroplastos , Toxinas Marinhas , Microcistinas , Fosfoproteínas Fosfatases , Microcistinas/toxicidade , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Arabidopsis/efeitos dos fármacos , Cianobactérias/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Synechococcus/efeitos dos fármacos
14.
Nat Commun ; 15(1): 3122, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600073

RESUMO

In chloroplasts, insertion of proteins with multiple transmembrane domains (TMDs) into thylakoid membranes usually occurs in a co-translational manner. Here, we have characterized a thylakoid protein designated FPB1 (Facilitator of PsbB biogenesis1) which together with a previously reported factor PAM68 (Photosynthesis Affected Mutant68) is involved in assisting the biogenesis of CP47, a subunit of the Photosystem II (PSII) core. Analysis by ribosome profiling reveals increased ribosome stalling when the last TMD segment of CP47 emerges from the ribosomal tunnel in fpb1 and pam68. FPB1 interacts with PAM68 and both proteins coimmunoprecipitate with SecY/E and Alb3 as well as with some ribosomal components. Thus, our data indicate that, in coordination with the SecY/E translocon and the Alb3 integrase, FPB1 synergistically cooperates with PAM68 to facilitate the co-translational integration of the last two CP47 TMDs and the large loop between them into thylakoids and the PSII core complex.


Assuntos
Complexo de Proteína do Fotossistema II , Tilacoides , Cloroplastos/metabolismo , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema II/metabolismo , Ribossomos/metabolismo , Tilacoides/metabolismo
15.
Ecotoxicol Environ Saf ; 276: 116307, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38593497

RESUMO

In recent decades, there has been increasing interest in elucidating the role of sulfur-containing compounds in plant metabolism, particularly emphasizing their function as signaling molecules. Among these, thiocyanate (SCN-), a compound imbued with sulfur and nitrogen, has emerged as a significant environmental contaminant frequently detected in irrigation water. This compound is known for its potential to adversely impact plant growth and agricultural yield. Although adopting exogenous SCN- as a nitrogen source in plant cells has been the subject of thorough investigation, the fate of sulfur resulting from the assimilation of exogenous SCN- has not been fully explored. There is burgeoning curiosity in probing the fate of SCN- within plant systems, especially considering the possible generation of the gaseous signaling molecule, hydrogen sulfide (H2S) during the metabolism of SCN-. Notably, the endogenous synthesis of H2S occurs predominantly within chloroplasts, the cytosol, and mitochondria. In contrast, the production of H2S following the assimilation of exogenous SCN- is explicitly confined to chloroplasts and mitochondria. This phenomenon indicates complex interplay and communication among various subcellular organelles, influencing signal transduction and other vital physiological processes. This review, augmented by a small-scale experimental study, endeavors to provide insights into the functional characteristics of H2S signaling in plants subjected to SCN--stress. Furthermore, a comparative analysis of the occurrence and trajectory of endogenous H2S and H2S derived from SCN--assimilation within plant organisms was performed, providing a focused lens for a comprehensive examination of the multifaceted roles of H2S in rice plants. By delving into these dimensions, our objective is to enhance the understanding of the regulatory mechanisms employed by the gasotransmitter H2S in plant adaptations and responses to SCN--stress, yielding invaluable insights into strategies for plant resilience and adaptive capabilities.


Assuntos
Sulfeto de Hidrogênio , Plantas , Transdução de Sinais , Tiocianatos , Sulfeto de Hidrogênio/metabolismo , Tiocianatos/metabolismo , Plantas/metabolismo , Gasotransmissores/metabolismo , Cloroplastos/metabolismo , Inativação Metabólica
16.
Nat Commun ; 15(1): 2792, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38555362

RESUMO

Plant photosynthesis contains two functional modules, the light-driven reactions in the thylakoid membrane and the carbon-fixing reactions in the chloroplast stroma. In nature, light availability for photosynthesis often undergoes massive and rapid fluctuations. Efficient and productive use of such variable light supply requires an instant crosstalk and rapid synchronization of both functional modules. Here, we show that this communication involves the stromal exposed C-terminus of the thylakoid K+-exchange antiporter KEA3, which regulates the ΔpH across the thylakoid membrane and therefore pH-dependent photoprotection. By combining in silico, in vitro, and in vivo approaches, we demonstrate that the KEA3 C-terminus senses the energy state of the chloroplast in a pH-dependent manner and regulates transport activity in response. Together our data pinpoint a regulatory feedback loop by which the stromal energy state orchestrates light capture and photoprotection via multi-level regulation of KEA3.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Tilacoides/metabolismo , Prótons , Antiporters/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fotossíntese/fisiologia , Cloroplastos/metabolismo , Luz
17.
Methods Mol Biol ; 2776: 3-20, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38502495

RESUMO

The emergence of thylakoid membranes in cyanobacteria is a key event in the evolution of all oxygenic photosynthetic cells, from prokaryotes to eukaryotes. Recent analyses show that they could originate from a unique lipid phase transition rather than from a supposed vesicular budding mechanism. Emergence of thylakoids coincided with the great oxygenation event, more than two billion years ago. The acquisition of semi-autonomous organelles, such as the mitochondrion, the chloroplast, and, more recently, the chromatophore, is a critical step in the evolution of eukaryotes. They resulted from primary endosymbiotic events that seem to share general features, i.e., an acquisition of a bacterium/cyanobacteria likely via a phagocytic membrane, a genome reduction coinciding with an escape of genes from the organelle to the nucleus, and, finally, the appearance of an active system translocating nuclear-encoded proteins back to the organelles. An intense mobilization of foreign genes of bacterial origin, via horizontal gene transfers, plays a critical role. Some third partners, like Chlamydia, might have facilitated the transition from cyanobacteria to the early chloroplast. This chapter further details our current understanding of primary endosymbiosis, focusing on primary chloroplasts, thought to have appeared over a billion years ago, and the chromatophore, which appeared around a hundred years ago.


Assuntos
Cromatóforos , Cianobactérias , Tilacoides/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Fotossíntese/genética , Cianobactérias/genética , Cianobactérias/metabolismo , Eucariotos , Simbiose/genética
18.
Methods Mol Biol ; 2776: 137-149, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38502501

RESUMO

Plant cell chloroplasts are bounded by a two-membrane envelope. Their photosynthetic function is based on the development of an operational large internal membrane network, called the thylakoids, and on enzymatic processes present in the chloroplast matrix, called the stroma. Thylakoid membranes are distinct from the chloroplast envelope, and their biogenesis is dependent on biosynthetic and transport activities specific of the chloroplast envelope. Starting with the isolation of intact chloroplasts, the method presents the separation by differential centrifugation of the three compartments. A protocol is detailed for leaves of spinach, Arabidopsis or pea.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Magnoliopsida , Tilacoides/metabolismo , Cloroplastos/metabolismo , Arabidopsis/metabolismo , Folhas de Planta , Proteínas de Arabidopsis/metabolismo
19.
Methods Mol Biol ; 2776: 63-88, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38502498

RESUMO

Plastids represent a largely diverse group of organelles in plant and algal cells that have several common features but also a broad spectrum of morphological, ultrastructural, biochemical, and physiological differences. Plastids and their structural and metabolic diversity significantly contribute to the functionality and developmental flexibility of the plant body throughout its lifetime. In addition to the multiple roles of given plastid types, this diversity is accomplished in some cases by interconversions between different plastids as a consequence of developmental and environmental signals that regulate plastid differentiation and specialization. In addition to basic plastid structural features, the most important plastid types, the newly characterized peculiar plastids, and future perspectives in plastid biology are also provided in this chapter.


Assuntos
Cloroplastos , Embriófitas , Cloroplastos/genética , Cloroplastos/metabolismo , Plastídeos/metabolismo , Embriófitas/genética , Plantas/metabolismo
20.
Methods Mol Biol ; 2776: 151-159, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38502502

RESUMO

The outer and the inner membranes of the chloroplast envelope, also called OEM and IEM, have distinct lipid and protein compositions. They host molecular systems involved in the biogenesis of the organelle, its cellular function, and its communication with other compartments. Here we describe a method for the isolation of these two membranes starting from intact chloroplast preparations, with two alternative procedures based on the starting material. One was developed from spinach leaves, the other from pea leaves. The two procedures differ in the method used to isolate and rupture chloroplasts and separate each membrane.


Assuntos
Membranas Intracelulares , Magnoliopsida , Membranas Intracelulares/metabolismo , Magnoliopsida/metabolismo , Cloroplastos/metabolismo , Proteínas de Membrana/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...