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1.
BMC Plant Biol ; 21(1): 406, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34488627

RESUMO

BACKGROUND: Plant mitochondrial transcription termination factor (mTERF) family members play important roles in development and stress tolerance through regulation of organellar gene expression. However, their molecular functions have yet to be clearly defined. RESULTS: Here an mTERF gene V14 was identified by fine mapping using a conditional albino mutant v14 that displayed albinism only in the first two true leaves, which was confirmed by transgenic complementation tests. Subcellular localization and real-time PCR analyses indicated that V14 encodes a chloroplastic protein ubiquitously expressed in leaves while spiking in the second true leaf. Chloroplastic gene expression profiling in the pale leaves of v14 through real-time PCR and Northern blotting analyses showed abnormal accumulation of the unprocessed transcripts covering the rpoB-rpoC1 and/or rpoC1-rpoC2 intercistronic regions accompanied by reduced abundance of the mature rpoC1 and rpoC2 transcripts, which encode two core subunits of the plastid-encoded plastid RNA polymerase (PEP). Subsequent immunoblotting analyses confirmed the reduced accumulation of RpoC1 and RpoC2. A light-inducible photosynthetic gene psbD was also found down-regulated at both the mRNA and protein levels. Interestingly, such stage-specific aberrant posttranscriptional regulation and psbD expression can be reversed by high temperatures (30 ~ 35 °C), although V14 expression lacks thermo-sensitivity. Meanwhile, three V14 homologous genes were found heat-inducible with similar temporal expression patterns, implicating their possible functional redundancy to V14. CONCLUSIONS: These data revealed a critical role of V14 in chloroplast development, which impacts, in a stage-specific and thermo-sensitive way, the appropriate processing of rpoB-rpoC1-rpoC2 precursors and the expression of certain photosynthetic proteins. Our findings thus expand the knowledge of the molecular functions of rice mTERFs and suggest the contributions of plant mTERFs to photosynthesis establishment and temperature acclimation.


Assuntos
Oryza/metabolismo , Fotossíntese/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Plântula/fisiologia , Aclimatação , Cloroplastos/fisiologia , Regulação da Expressão Gênica de Plantas , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/genética , Temperatura
2.
Nat Commun ; 12(1): 5092, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34429430

RESUMO

Development of a versatile, sustainable and efficient photosynthesis system that integrates intricate catalytic networks and energy modules at the same location is of considerable future value to energy transformation. In the present study, we develop a coenzyme-mediated supramolecular host-guest semibiological system that combines artificial and enzymatic catalysis for photocatalytic hydrogen evolution from alcohol dehydrogenation. This approach involves modification of the microenvironment of a dithiolene-embedded metal-organic cage to trap an organic dye and NADH molecule simultaneously, serving as a hydrogenase analogue to induce effective proton reduction inside the artificial host. This abiotic photocatalytic system is further embedded into the pocket of the alcohol dehydrogenase to couple enzymatic alcohol dehydrogenation. This host-guest approach allows in situ regeneration of NAD+/NADH couple to transfer protons and electrons between the two catalytic cycles, thereby paving a unique avenue for a synergic combination of abiotic and biotic synthetic sequences for photocatalytic fuel and chemical transformation.


Assuntos
Etanol/química , Fotossíntese/fisiologia , Luz Solar , Catálise , Corantes , Elétrons , Hidrogênio/química , Hidrogenase/química , Cinética , Ligantes , Simulação de Acoplamento Molecular
3.
Int J Mol Sci ; 22(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34360890

RESUMO

The thylakoid lumen houses proteins that are vital for photosynthetic electron transport, including water-splitting at photosystem (PS) II and shuttling of electrons from cytochrome b6f to PSI. Other lumen proteins maintain photosynthetic activity through biogenesis and turnover of PSII complexes. Although all lumen proteins are soluble, these known details have highlighted interactions of some lumen proteins with thylakoid membranes or thylakoid-intrinsic proteins. Meanwhile, the functional details of most lumen proteins, as well as their distribution between the soluble and membrane-associated lumen fractions, remain unknown. The current study isolated the soluble free lumen (FL) and membrane-associated lumen (MAL) fractions from Arabidopsis thaliana, and used gel- and mass spectrometry-based proteomics methods to analyze the contents of each proteome. These results identified 60 lumenal proteins, and clearly distinguished the difference between the FL and MAL proteomes. The most abundant proteins in the FL fraction were involved in PSII assembly and repair, while the MAL proteome was enriched in proteins that support the oxygen-evolving complex (OEC). Novel proteins, including a new PsbP domain-containing isoform, as well as several novel post-translational modifications and N-termini, are reported, and bi-dimensional separation of the lumen proteome identified several protein oligomers in the thylakoid lumen.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Membranas Intracelulares/metabolismo , Complexo de Proteína do Fotossistema II/química , Complexo de Proteína do Fotossistema II/metabolismo , Proteoma , Tilacoides/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Eletroforese em Gel Bidimensional/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Espectrometria de Massas/métodos , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/genética , Filogenia , Processamento de Proteína Pós-Traducional , Proteômica/métodos
4.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445664

RESUMO

The target of rapamycin (TOR) protein kinase is an atypical Ser/Thr protein kinase and evolutionally conserved among yeasts, plants, and mammals. TOR has been established as a central hub for integrating nutrient, energy, hormone, and environmental signals in all the eukaryotes. Despite the conserved functions across eukaryotes, recent research has shed light on the multifaceted roles of TOR signaling in plant-specific functional and mechanistic features. One of the most specific features is the involvement of TOR in plant photosynthesis. The recent development of tools for the functional analysis of plant TOR has helped to uncover the involvement of TOR signaling in several steps preceding photoautotrophy and maintenance of photosynthesis. Here, we present recent novel findings relating to TOR signaling and its roles in regulating plant photosynthesis, including carbon nutrient sense, light absorptions, and leaf and chloroplast development. We also provide some gaps in our understanding of TOR function in photosynthesis that need to be addressed in the future.


Assuntos
Fotossíntese/fisiologia , Serina-Treonina Quinases TOR/metabolismo , Autofagia , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/fisiologia
5.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445145

RESUMO

The main goal of growing plants under various photoperiods is to optimize photosynthesis for using the effect of day length that often acts on plants in combination with biotic and/or abiotic stresses. In this study, Brassica juncea plants were grown under four different day-length regimes, namely., 8 h day/16 h night, 12 h day/12 h night, 16 h day/8 h night, and continuous light, and were infected with a necrotrophic fungus Alternaria brassicicola. The development of necroses on B. juncea leaves was strongly influenced by leaf position and day length. The largest necroses were formed on plants grown under a 16 h day/8 h night photoperiod at 72 h post-inoculation (hpi). The implemented day-length regimes had a great impact on leaf morphology in response to A. brassicicola infection. They also influenced the chlorophyll and carotenoid contents and photosynthesis efficiency. Both the 1st (the oldest) and 3rd infected leaves showed significantly higher minimal fluorescence (F0) compared to the control leaves. Significantly lower values of other investigated chlorophyll a fluorescence parameters, e.g., maximum quantum yield of photosystem II (Fv/Fm) and non-photochemical quenching (NPQ), were observed in both infected leaves compared to the control, especially at 72 hpi. The oldest infected leaf, of approximately 30% of the B. juncea plants, grown under long-day and continuous light conditions showed a 'green island' phenotype in the form of a green ring surrounding an area of necrosis at 48 hpi. This phenomenon was also reflected in changes in the chloroplast's ultrastructure and accelerated senescence (yellowing) in the form of expanding chlorosis. Further research should investigate the mechanism and physiological aspects of 'green islands' formation in this pathosystem.


Assuntos
Alternaria/patogenicidade , Mostardeira/microbiologia , Mostardeira/fisiologia , Necrose/microbiologia , Necrose/patologia , Fotossíntese/fisiologia , Doenças das Plantas/microbiologia , Carotenoides/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Fluorescência , Mostardeira/metabolismo , Necrose/metabolismo , Fotoperíodo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
6.
Int J Mol Sci ; 22(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203321

RESUMO

Bread wheat (Triticum aestivum) is less adaptable to high temperatures than other major cereals. Previous studies of the effects of high temperature on wheat focused on the reproductive stage. There are few reports on yield after high temperatures at other growth stages. Understanding growth-stage-specific responses to heat stress will contribute to the development of tolerant lines suited to high temperatures at various stages. We exposed wheat cultivar "Norin 61" to high temperature at three growth stages: seedling-tillering (GS1), tillering-flowering (GS2), and flowering-maturity (GS3). We compared each condition based on agronomical traits, seed maturity, and photosynthesis results. Heat at GS2 reduced plant height and number of grains, and heat at GS3 reduced the grain formation period and grain weight. However, heat at GS1 reduced senescence and prolonged grain formation, increasing grain weight without reducing yield. These data provide fundamental insights into the biochemical and molecular adaptations of bread wheat to high-temperature stresses and have implications for the development of wheat lines that can respond to high temperatures at various times of the year.


Assuntos
Triticum/metabolismo , Flores/metabolismo , Temperatura Alta , Fotossíntese/genética , Fotossíntese/fisiologia , Sementes/metabolismo , Triticum/genética
7.
J Plant Physiol ; 263: 153460, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34217838

RESUMO

Ethylene is a gaseous hormone with a well-established role in the regulation of plant growth and development. However, its role in the modulation of carbon assimilation and central metabolism remains unclear. Here, we investigated the morphophysiological and biochemical responses of tomato plants (Solanum lycopersicum) following the application of ethylene in the form of ethephon (CEPA - 2-chloroethylphosphonic acid), forcing the classical triple response phenotype. CEPA-treated plants were characterized by growth inhibition, as revealed by significant reductions in both shoot and root dry weights, coupled with a reduced number of leaves and lower specific leaf area. Growth inhibition was associated with a reduction in carbon assimilation due to both lower photosynthesis rates and stomatal conductance, coupled with impairments in carbohydrate turnover. Furthermore, exogenous ethylene led to the accumulation of cell wall compounds (i.e., cellulose and lignin) and phenolics, indicating that exposure to exogenous ethylene also led to changes in specialized metabolism. Collectively, our findings demonstrate that exogenous ethylene disrupts plant growth and leaf structure by affecting both central and specialized metabolism, especially that involved in carbohydrate turnover and cell wall biosynthesis, ultimately leading to metabolic responses that mimic stress situations.


Assuntos
Etilenos/metabolismo , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/genética , Lycopersicon esculentum/metabolismo , Fotossíntese/fisiologia , Reguladores de Crescimento de Plantas/genética , Reguladores de Crescimento de Plantas/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo
8.
Int J Mol Sci ; 22(11)2021 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34204152

RESUMO

In nature, plants are exposed to an ever-changing environment with increasing frequencies of multiple abiotic stresses. These abiotic stresses act either in combination or sequentially, thereby driving vegetation dynamics and limiting plant growth and productivity worldwide. Plants' responses against these combined and sequential stresses clearly differ from that triggered by an individual stress. Until now, experimental studies were mainly focused on plant responses to individual stress, but have overlooked the complex stress response generated in plants against combined or sequential abiotic stresses, as well as their interaction with each other. However, recent studies have demonstrated that the combined and sequential abiotic stresses overlap with respect to the central nodes of their interacting signaling pathways, and their impact cannot be modelled by swimming in an individual extreme event. Taken together, deciphering the regulatory networks operative between various abiotic stresses in agronomically important crops will contribute towards designing strategies for the development of plants with tolerance to multiple stress combinations. This review provides a brief overview of the recent developments in the interactive effects of combined and sequentially occurring stresses on crop plants. We believe that this study may improve our understanding of the molecular and physiological mechanisms in untangling the combined stress tolerance in plants, and may also provide a promising venue for agronomists, physiologists, as well as molecular biologists.


Assuntos
Produtos Agrícolas/fisiologia , Estresse Fisiológico/fisiologia , Produtos Agrícolas/crescimento & desenvolvimento , Homeostase , Fotossíntese/fisiologia , Espécies Reativas de Oxigênio/metabolismo
9.
BMC Plant Biol ; 21(1): 318, 2021 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-34217217

RESUMO

BACKGROUND: Cassava (Manihot esculenta Crantz) efficiently accumulates starch in its storage roots. However, how photosynthates are transported from the leaves to the phloem (especially how they are unloaded into parenchymal cells of storage roots) remains unclear. RESULTS: Here, we investigated the sucrose unloading pattern and its impact on cassava storage root development using microstructural and physiological analyses, namely, carboxyfluorescein (CF) and C14 isotope tracing. The expression profiling of genes involved in symplastic and apoplastic transport was performed, which included enzyme activity, protein gel blot analysis, and transcriptome sequencing analyses. These finding showed that carbohydrates are transported mainly in the form of sucrose, and more than 54.6% was present in the stem phloem. Sucrose was predominantly unloaded symplastically from the phloem into storage roots; in addition, there was a shift from apoplastic to symplastic unloading accompanied by the onset of root swelling. Statistical data on the microstructures indicated an enrichment of plasmodesmata within sieve, companion, and parenchyma cells in the developing storage roots of a cultivar but not in a wild ancestor. Tracing tests with CF verified the existence of a symplastic channel, and [14C] Suc demonstrated that sucrose could rapidly diffuse into root parenchyma cells from phloem cells. The relatively high expression of genes encoding sucrose synthase and associated proteins appeared in the middle and late stages of storage roots but not in primary fibrous roots, or secondary fibrous roots. The inverse expression pattern of sucrose transporters, cell wall acid invertase, and soluble acid invertase in these corresponding organs supported the presence of a symplastic sucrose unloading pathway. The transcription profile of genes involved in symplastic unloading and their significantly positive correlation with the starch yield at the population level confirmed that symplastic sucrose transport is vitally important in the development of cassava storage roots. CONCLUSIONS: In this study, we revealed that the cassava storage root phloem sucrose unloading pattern was predominantly a symplastic unloading pattern. This pattern is essential for efficient starch accumulation in high-yielding varieties compared with low-yielding wild ancestors.


Assuntos
Manihot/metabolismo , Floema/fisiologia , Fotossíntese/fisiologia , Raízes de Plantas/metabolismo , Amido/metabolismo , Transporte Biológico , Biomassa , Parede Celular/metabolismo , Difusão , Fluoresceínas/metabolismo , Regulação da Expressão Gênica de Plantas , Manihot/genética , Modelos Biológicos , Floema/citologia , Floema/ultraestrutura , Plasmodesmos/metabolismo , Frações Subcelulares/metabolismo , Sacarose/metabolismo , Açúcares/metabolismo
10.
Int J Mol Sci ; 22(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203436

RESUMO

The beneficial role of fungi from the Trichoderma genus and its secondary metabolites in promoting plant growth, uptake and use efficiency of macronutrients and oligo/micro-nutrients, activation of plant secondary metabolism and plant protection from diseases makes it interesting for application in environmentally friendly agriculture. However, the literature data on the effect of Trichoderma inoculation on tomato fruit quality is scarce. Commercially used tomato cultivars were chosen in combination with indigenous Trichodrema species previously characterized on molecular and biochemical level, to investigate the effect of Trichoderma on photosynthetic characteristics and fruit quality of plants grown in organic system of production. Examined cultivars differed in the majority of examined parameters. Response of cultivar Gruzanski zlatni to Trichoderma application was more significant. As a consequence of increased epidermal flavonols and decreased chlorophyll, the nitrogen balance index in leaves has decreased, indicating a shift from primary to secondary metabolism. The quality of its fruit was altered in the sense of increased total flavonoids content, decreased starch, increased Bioaccumulation Index (BI) for Fe and Cr, and decreased BI for heavy metals Ni and Pb. Higher expression of swolenin gene in tomato roots of more responsive tomato cultivar indicates better root colonization, which correlates with observed positive effects of Trichodrema.


Assuntos
Trichoderma/patogenicidade , Flavonoides/metabolismo , Frutas/microbiologia , Hypocreales/patogenicidade , Fotossíntese/fisiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/microbiologia
11.
J Plant Physiol ; 263: 153469, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34252704

RESUMO

The major effect of nitrogen (N) deficiency is the inhibition on CO2 assimilation regulated by light energy absorption, transport and conversion, as well as N allocation. In this study, a yellow-green wheat mutant (Jimai5265yg) and its wild type (Jimai5265, WT) were compared between 0 mM N (N0) and 14 mM N (N14) treatments using hydroponic experiments. The mutant exhibited higher photosynthetic efficiency (An) than WT despite low chlorophyll (Chl) content in non-stressed conditions. The photosynthetic advantages of the mutant were maintained under N deficient condition. The quantitative analysis of limitations to photosynthesis revealed that CO2 diffusion associated with mesophyll conductance (gm) was the dominant limitation. Relative easiness to gain CO2 in the chloroplast contributed to the higher An of Jimai5265yg. N deficiency induced the photoinhibition of PSII, but the cyclic electron transport and photochemical activity of PSI was higher in Jimai5265yg compared to Jimai5265, which was a protective mechanism to avoid photodamage. Because of the sharp drop of An, N deficient seedlings had much lower photosynthetic N use efficiency (PNUE). However, N deficiency increased the relative content of photosynthetic N (Npsn) and decreased the relative content of storage N (Nstore). The range of change in N partitioning induced by N deficiency was smaller for Jimai5265yg compared to WT. The less insensitive to N deficiency for the mutant in terms of photosynthetic property and N partitioning suggested that gm, cyclic electron transport around PSI and more optimal N partitioning pattern is necessary to sustain photosynthesis under N deficient condition.


Assuntos
Clorofila/metabolismo , Células do Mesofilo/metabolismo , Nitrogênio/deficiência , Nitrogênio/metabolismo , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/metabolismo , Triticum/genética , Triticum/metabolismo , Clorofila/genética , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Transporte de Elétrons/genética , Transporte de Elétrons/fisiologia , Variação Genética , Genótipo , Mutação , Fotossíntese/genética , Complexo de Proteína do Fotossistema II/genética
12.
J Phys Chem Lett ; 12(29): 6967-6973, 2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34283617

RESUMO

In photosynthesis, the efficiency with which a photogenerated exciton reaches the reaction center is dictated by chromophore energies and the arrangement of chromophores in the supercomplex. Here, we explore the interplay between the arrangement of light-harvesting antennae and the efficiency of exciton transport in purple bacterial photosynthesis. Using a Miller-Abrahams-based exciton hopping model, we compare different arrangements of light-harvesting proteins on the intracytoplasmic membrane. We find that arrangements with aggregated LH1s have a higher efficiency than arrangements with randomly distributed LH1s in a wide range of physiological light fluences. This effect is robust to the introduction of defects on the intracytoplasmic membrane. Our result explains the absence of species with aggregated LH1 arrangements in low-light niches and the large increase seen in the expression of LH1 dimer complexes in high fluences. We suggest that the effect seen in our study is an adaptive strategy toward solar light fluence across different purple bacterial species.


Assuntos
Proteínas de Bactérias/química , Membrana Celular/química , Complexos de Proteínas Captadores de Luz/química , Proteobactérias/química , Transferência de Energia , Método de Monte Carlo , Fotossíntese/fisiologia
13.
Int J Mol Sci ; 22(10)2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34067635

RESUMO

The color of bracts generally turns yellow or black from green during cereal grain development. However, the impact of these phenotypic changes on photosynthetic physiology during black bract formation remains unclear. Two oat cultivars (Avena sativa L.), 'Triple Crown' and 'Qinghai 444', with yellow and black bracts, respectively, were found to both have green bracts at the heading stage, but started to turn black at the flowering stage and become blackened at the milk stage for 'Qinghai 444'. Their photosynthetic characteristics were analyzed and compared, and the key genes, proteins and regulatory pathways affecting photosynthetic physiology were determined in 'Triple Crown' and 'Qinghai 444' bracts. The results show that the actual PSII photochemical efficiency and PSII electron transfer rate of 'Qinghai 444' bracts had no significant changes at the heading and milk stages but decreased significantly (p < 0.05) at the flowering stage compared with 'Triple Crown'. The chlorophyll content decreased, the LHCII involved in the assembly of supercomplexes in the thylakoid membrane was inhibited, and the expression of Lhcb1 and Lhcb5 was downregulated at the flowering stage. During this critical stage, the expression of Bh4 and C4H was upregulated, and the biosynthetic pathway of p-coumaric acid using tyrosine and phenylalanine as precursors was also enhanced. Moreover, the key upregulated genes (CHS, CHI and F3H) of anthocyanin biosynthesis might complement the impaired PSII activity until recovered at the milk stage. These findings provide a new insight into how photosynthesis alters during the process of oat bract color transition to black.


Assuntos
Avena/metabolismo , Flores/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Antocianinas/genética , Antocianinas/metabolismo , Clorofila/metabolismo , Expressão Gênica/genética , Regulação da Expressão Gênica de Plantas/genética , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/fisiologia , Tilacoides/metabolismo
14.
Molecules ; 26(11)2021 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-34070994

RESUMO

Ozone (O3) entry into plant leaves depends on atmospheric O3 concentration, exposure time and openness of stomata. O3 negatively impacts photosynthesis rate (A) and might induce the release of reactive volatile organic compounds (VOCs) that can quench O3, and thereby partly ameliorate O3 stress. Water stress reduces stomatal conductance (gs) and O3 uptake and can affect VOC release and O3 quenching by VOC, but the interactive effects of O3 exposure and water stress, as possibly mediated by VOC, are poorly understood. Well-watered (WW) and water-stressed (WS) Brassica nigra plants were exposed to 250 and 550 ppb O3 for 1 h, and O3 uptake rates, photosynthetic characteristics and VOC emissions were measured through 22 h recovery. The highest O3 uptake was observed in WW plants exposed to 550 ppb O3 with the greatest reduction and poorest recovery of gs and A, and elicitation of lipoxygenase (LOX) pathway volatiles 10 min-1.5 h after exposure indicating cellular damage. Ozone uptake was similar in 250 ppb WW and 550 ppb WS plants and, in both treatments, O3-dependent reduction in photosynthetic characteristics was moderate and fully reversible, and VOC emissions were little affected. Water stress alone did not affect the total amount and composition of VOC emissions. The results indicate that drought ameliorated O3 stress by reducing O3 uptake through stomatal closure and the two stresses operated in an antagonistic manner in B. nigra.


Assuntos
Mostardeira/metabolismo , Fotossíntese/fisiologia , Estresse Fisiológico/fisiologia , Transporte Biológico/fisiologia , Desidratação/metabolismo , Desidratação/fisiopatologia , Secas , Oxigênio/química , Oxigênio/metabolismo , Ozônio/metabolismo , Folhas de Planta/metabolismo , Estômatos de Plantas/metabolismo , Compostos Orgânicos Voláteis/química
15.
Methods Mol Biol ; 2290: 229-252, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34009594

RESUMO

Photosynthetic cyanobacteria are not only model organisms for studying photosynthesis and biological cycling of carbon in biosphere but also potential "green microbial factories" to produce renewable fuels and chemicals, due to their capability to utilizing solar energy and CO2. Therefore, strategies for gene regulation and carbon flux redirection are important for both fundamental research and metabolic engineering of cyanobacteria. To address the challenges, regulatory tools based on artificial small RNAs have been developed with satisfactory effects for single or multiple gene(s) regulation in various cyanobacterial species. When combined with the promoters of varying gradient strength and the inducible switches developed in recent years, it is now feasible to realize precise gene regulation in photosynthetic cyanobacteria for producing fuels and chemicals. Here in this chapter, we provide a detailed introduction of the design principles and constructing methods of the artificial sRNA tools to achieve accurate inducible regulation of cyanobacterial gene(s).


Assuntos
Cianobactérias/genética , Regulação Bacteriana da Expressão Gênica/genética , Pequeno RNA não Traduzido/síntese química , Biocombustíveis , Carbono/metabolismo , Ciclo do Carbono , Dióxido de Carbono/metabolismo , Expressão Gênica/genética , Engenharia Metabólica/métodos , Fotossíntese/fisiologia , RNA/metabolismo , Pequeno RNA não Traduzido/metabolismo , Biologia Sintética/métodos
16.
Plant Cell ; 33(3): 623-641, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33955495

RESUMO

Leaf spongy mesophyll cells form an interconnected network of branched cells and intercellular spaces to maximize the surface area available for light capture and photosynthetic gas exchange. To investigate the morphogenetic events leading to cell separation and branching in Arabidopsis thaliana, we used mesophyll-specific promoters to facilitate imaging of mesophyll cell shape and microtubule (MT) organization over multiple spatiotemporal scales without interference from the overlying epidermal cells. We show that cells enlarge by selective expansion of cell wall regions in contact with intercellular spaces. Cell-cell contacts remain relatively fixed in size, forming the termini of interconnecting branches. Surprisingly, classic schizogeny (de-adhesion of neighboring cells) is relatively infrequent, being related to the local topology of cell junctions during early expansion. Intercellular spaces cue the position of stable MT bundles, which in turn promote efficient dilation of intercellular spaces and cell branching. Our data provide insights into mesophyll morphogenesis and MT organization and lay the groundwork for future investigations.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Células do Mesofilo/metabolismo , Microtúbulos/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Ciclo Celular/genética , Ciclo Celular/fisiologia , Proliferação de Células/genética , Proliferação de Células/fisiologia , Fotossíntese/genética , Fotossíntese/fisiologia
17.
Methods Mol Biol ; 2295: 81-97, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34047973

RESUMO

Algae are ecologically important organisms and are widely used for basic research, with a focus on for example photosynthesis, evolution, and lipid metabolism. Many biosynthetic pathways of algal lipids have been deciphered using available genomic information. Here we describe methods for lipid analyses from three representative algae, including Archaeplastida, the SAR lineage (Stramenopiles, Alveolata, Rhizaria), and Excavata. Archaeplastida acquired their plastids by primary endosymbiosis, and the others by secondary endosymbiosis with a Rhodophyceae-type plastid in SAR and a Chlorophyceae-type plastid in Excavata (Euglenozoa). Analytical methods for these algae are described for membrane lipids and neutral lipids including triacylglycerol and wax esters.


Assuntos
Carofíceas/metabolismo , Euglênidos/metabolismo , Lipídeos/análise , Caráceas/genética , Evolução Molecular , Microalgas/metabolismo , Fotossíntese/fisiologia , Filogenia , Plastídeos/metabolismo , Rodófitas/genética , Estramenópilas/genética , Simbiose/fisiologia
18.
Plant Physiol ; 185(4): 1894-1902, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33793957

RESUMO

Conversion of light energy into chemical energy through photosynthesis in the chloroplasts of photosynthetic organisms is essential for photoautotrophic growth, and non-photochemical quenching (NPQ) of excess light energy prevents the generation of reactive oxygen species and maintains efficient photosynthesis under high light. In the unicellular green alga Chlamydomonas reinhardtii, NPQ is activated as a photoprotective mechanism through wavelength-specific light signaling pathways mediated by the phototropin (blue light) and ultra-violet (UV) light photoreceptors, but the biological significance of photoprotection activation by light with different qualities remains poorly understood. Here, we demonstrate that NPQ-dependent photoprotection is activated more rapidly by UV than by visible light. We found that induction of gene expression and protein accumulation related to photoprotection was significantly faster and greater in magnitude under UV treatment compared with that under blue- or red-light treatment. Furthermore, the action spectrum of UV-dependent induction of photoprotective factors implied that C. reinhardtii senses relatively long-wavelength UV (including UV-A/B), whereas the model dicot plant Arabidopsis (Arabidopsis thaliana) preferentially senses relatively short-wavelength UV (mainly UV-B/C) for induction of photoprotective responses. Therefore, we hypothesize that C. reinhardtii developed a UV response distinct from that of land plants.


Assuntos
Arabidopsis/genética , Arabidopsis/fisiologia , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/fisiologia , Complexos de Proteínas Captadores de Luz/fisiologia , Fotossíntese/fisiologia , Raios Ultravioleta
19.
Plant Physiol ; 185(4): 1500-1522, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33793915

RESUMO

Photosynthesis is not only essential for plants, but it also sustains life on Earth. Phytohormones play crucial roles in developmental processes, from organ initiation to senescence, due to their role as growth and developmental regulators, as well as their central role in the regulation of photosynthesis. Furthermore, phytohormones play a major role in photoprotection of the photosynthetic apparatus under stress conditions. Here, in addition to discussing our current knowledge on the role of the phytohormones auxin, cytokinins, gibberellins, and strigolactones in promoting photosynthesis, we will also highlight the role of abscisic acid beyond stomatal closure in modulating photosynthesis and photoprotection under various stress conditions through crosstalk with ethylene, salicylates, jasmonates, and brassinosteroids. Furthermore, the role of phytohormones in controlling the production and scavenging of photosynthesis-derived reactive oxygen species, the duration and extent of photo-oxidative stress and redox signaling under stress conditions will be discussed in detail. Hormones have a significant impact on the regulation of photosynthetic processes in plants under both optimal and stress conditions, with hormonal interactions, complementation, and crosstalk being important in the spatiotemporal and integrative regulation of photosynthetic processes during organ development at the whole-plant level.


Assuntos
Adaptação Fisiológica/fisiologia , Fenômenos Bioquímicos/fisiologia , Luz/efeitos adversos , Fotossíntese/fisiologia , Reguladores de Crescimento de Plantas/metabolismo , Estresse Fisiológico/fisiologia , Estrutura Molecular
20.
Nat Commun ; 12(1): 2291, 2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33863895

RESUMO

Plants need to protect themselves from excess light, which causes photo-oxidative damage and lowers the efficiency of photosynthesis. Photosystem II subunit S (PsbS) is a pH sensor protein that plays a crucial role in plant photoprotection by detecting thylakoid lumen acidification in excess light conditions via two lumen-faced glutamates. However, how PsbS is activated under low-pH conditions is unknown. To reveal the molecular response of PsbS to low pH, here we perform an NMR, FTIR and 2DIR spectroscopic analysis of Physcomitrella patens PsbS and of the E176Q mutant in which an active glutamate has been replaced. The PsbS response mechanism at low pH involves the concerted action of repositioning of a short amphipathic helix containing E176 facing the lumen and folding of the luminal loop fragment adjacent to E71 to a 310-helix, providing clear evidence of a conformational pH switch. We propose that this concerted mechanism is a shared motif of proteins of the light-harvesting family that may control thylakoid inter-protein interactions driving photoregulatory responses.


Assuntos
Adaptação Fisiológica , Bryopsida/fisiologia , Luz/efeitos adversos , Complexo de Proteína do Fotossistema II/metabolismo , Estresse Fisiológico , Bryopsida/efeitos da radiação , Ácido Glutâmico/genética , Concentração de Íons de Hidrogênio/efeitos da radiação , Mutagênese Sítio-Dirigida , Ressonância Magnética Nuclear Biomolecular , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema II/isolamento & purificação , Complexo de Proteína do Fotossistema II/ultraestrutura , Conformação Proteica em alfa-Hélice , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Tilacoides/efeitos da radiação
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