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2.
Philos Trans R Soc Lond B Biol Sci ; 379(1914): 20230365, 2024 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-39343017

RESUMO

Plant glutathione transferases (GSTs) constitute a large and diverse family of enzymes that are involved in plant stress response, metabolism and defence, yet their physiological functions remain largely elusive. Consistent with the traditional view on GSTs across organisms as detoxification enzymes, in vitro most plant GSTs catalyse glutathionylation, conjugation of the tripeptide glutathione (GSH; γ-Glu-Cys-Gly) onto reactive molecules. However, when it comes to elucidating GST functions, it remains a key challenge that the endogenous plant glutathione conjugates (GS-conjugates) that would result from such glutathionylation reactions are rarely reported. Furthermore, GSTs often display high substrate promiscuity, and their proposed substrates are prone to spontaneous chemical reactions with GSH; hence, single-gene knockouts rarely provide clear chemotypes or phenotypes. In a few cases, GS-conjugates are demonstrated to be biosynthetic intermediates that are rapidly further metabolized towards a pathway end product, explaining their low abundance and rare detection. In this review, we summarize the current knowledge of plant GST functions and how and possibly why evolution has resulted in a broad and extensive expansion of the plant GST family. Finally, we demonstrate that endogenous GS-conjugates are more prevalent in plants than assumed and suggest they are overlooked as clues towards the identification of plant GST functions. This article is part of the theme issue 'The evolution of plant metabolism'.


Assuntos
Glutationa Transferase , Glutationa , Plantas , Glutationa Transferase/metabolismo , Glutationa Transferase/genética , Glutationa Transferase/química , Glutationa/metabolismo , Plantas/enzimologia , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética
3.
Plant Physiol Biochem ; 196: 807-820, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36863218

RESUMO

Seed germination is crucial for plant productivity, and the biochemical changes during germination affect seedling survival, plant health and yield. While the general metabolism of germination is extensively studied, the role of specialized metabolism is less investigated. We therefore analyzed the metabolism of the defense compound dhurrin during sorghum (Sorghum bicolor) grain germination and early seedling development. Dhurrin is a cyanogenic glucoside, which is catabolized into different bioactive compounds at other stages of plant development, but its fate and role during germination is unknown. We dissected sorghum grain into three different tissues and investigated dhurrin biosynthesis and catabolism at the transcriptomic, metabolomic and biochemical level. We further analyzed transcriptional signature differences of cyanogenic glucoside metabolism between sorghum and barley (Hordeum vulgare), which produces similar specialized metabolites. We found that dhurrin is de novo biosynthesized and catabolized in the growing embryonic axis as well as the scutellum and aleurone layer, two tissues otherwise mainly acknowledged for their involvement in release and transport of general metabolites from the endosperm to the embryonic axis. In contrast, genes encoding cyanogenic glucoside biosynthesis in barley are exclusively expressed in the embryonic axis. Glutathione transferase enzymes (GSTs) are involved in dhurrin catabolism and the tissue-resolved analysis of GST expression identified new pathway candidate genes and conserved GSTs as potentially important in cereal germination. Our study demonstrates a highly dynamic tissue- and species-specific specialized metabolism during cereal grain germination, highlighting the importance of tissue-resolved analyses and identification of specific roles of specialized metabolites in fundamental plant processes.


Assuntos
Grão Comestível , Sorghum , Grão Comestível/genética , Sorghum/genética , Sorghum/metabolismo , Transcriptoma , Metabolômica , Glucosídeos/metabolismo
4.
Plants (Basel) ; 12(3)2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36771583

RESUMO

Oat (Avena sativa) is susceptible to Fusarium head blight (FHB). The quality of oat grain is threatened by the accumulation of mycotoxins, particularly the trichothecene deoxynivalenol (DON), which also acts as a virulence factor for the main pathogen Fusarium graminearum. The plant can defend itself, e.g., by DON detoxification by UGT-glycosyltransferases (UTGs) and accumulation of PR-proteins, even though these mechanisms do not deliver effective levels of resistance. We studied the ability of the fungal biocontrol agent (BCA) Clonostachys rosea to reduce FHB and mycotoxin accumulation. Greenhouse trials showed that C. rosea-inoculation of oat spikelets at anthesis 3 days prior to F. graminearum inoculation reduced both the amount of Fusarium DNA (79%) and DON level (80%) in mature oat kernels substantially. DON applied to C. rosea-treated spikelets resulted in higher conversion of DON to DON-3-Glc than in mock treated plants. Moreover, there was a significant enhancement of expression of two oat UGT-glycosyltransferase genes in C. rosea-treated oat. In addition, C. rosea treatment activated expression of genes encoding four PR-proteins and a WRKY23-like transcription factor, suggesting that C. rosea may induce resistance in oat. Thus, C. rosea IK726 has strong potential to be used as a BCA against FHB in oat as it inhibits F. graminearum infection effectively, whilst detoxifying DON mycotoxin rapidly.

5.
Food Chem ; 366: 130562, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34289442

RESUMO

In this work, new approaches for the green extraction of polyphenols from sour cherry pomace were explored. Three Natural Deep Eutectic Solvents (NADES) systems based on choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and malic acid, urea, and fructose (MalA, Ur, and Fru) as hydrogen bond donors (HBD) were used. NADES systems were prepared by heating and stirring (H&S), ultrasound (US), and microwave (MW) methods. It was found that MW-assisted preparation was the fastest requiring less than 30 s. Polyphenol extraction from cherry pomace was performed also by three mentioned methods, and compared with conventional methods. MW extraction was the most rapid with less than 5 min necessary for the extract preparation. All three NADES systems were highly efficient for anthocyanin extraction, but the most efficient was ChCl:MalA system. Extract based on ChCl:MalA system was for 62.33% more efficient for anthocyanin extraction comparing with the conventional solvent.


Assuntos
Polifenóis , Prunus avium , Micro-Ondas , Extratos Vegetais , Solventes
6.
Food Chem ; 362: 130226, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118512

RESUMO

The focus of this study was to evaluate whether six choline chloride-based natural deep eutectic solvents (NADES) could serve as solvents for the extraction of bioactives from the leaves of Mentha piperita. NADES extracted significantly higher amounts of phenols from peppermint than 70% ethanol and may be useful in the extraction of targeted major compounds from peppermint, like rosmarinic acid, at a similar level as 70% ethanol. The microdilution method for in vitro antibacterial activity showed that all NADES exhibit bacterial growth inhibition at a lower concentration than 70% ethanol, especially NADESs containing organic acids. The majority of NADES extracts neutralize DPPH radical at a lower concentration than conventional solvent and showed similar ability to reduce Fe3+ to Fe2+ ions in FRAP assay. NADES can be useful in the isolation of phenolic compounds from plant sources and should be considered as novel, sustainable, and low-cost solvents with a variety of applications.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Mentha piperita/química , Fenóis/análise , Extratos Vegetais/farmacologia , Antibacterianos/química , Antioxidantes/química , Colina/química , Etanol/química , Recuperação de Fluorescência Após Fotodegradação , Testes de Sensibilidade Microbiana , Fenóis/química , Extratos Vegetais/química , Folhas de Planta/química , Solventes/química
7.
Sci Rep ; 9(1): 17986, 2019 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-31784602

RESUMO

The reproductive cycle of apple (Malus × domestica Borkh.) starts with the induction of floral development, however, first morphological changes within the bud appear during the following period of bud initiation. This study identifies the onset and duration of bud initiation in the apple cultivars 'Fuji' and 'Gala', characterized by biennial and non-biennial bearing behaviour, respectively, and describes the effect of crop load and heat accumulation on the temporal pattern of floral development. The onset of flower bud initiation in heavy cropping 'Gala' trees was delayed for 20 days compared to trees with no crop load, but the rate of initiation was not affected by crop load. Bud initiation on heavy cropping 'Fuji' trees was minor, whereas trees with no crop load started initiating buds 19 days earlier than those of 'Gala' despite the same cropping status and growing degree hours in a given year. The onset of bud initiation in 'Fuji' 'off' trees was 5 and 20 days after summer solstice, respectively, in two consecutive growing seasons, suggesting that this process is driven by heat accumulation rather than by daylength. The results indicate, that the genetic make-up of the cultivar determines the onset of bud initiation. This can be delayed by increasing crop loads and low temperatures at the beginning of the flower formation process.


Assuntos
Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Malus/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Adaptação Fisiológica/genética , Temperatura Baixa/efeitos adversos , Malus/genética , Fotoperíodo , Estações do Ano , Temperatura , Fatores de Tempo , Árvores
8.
Int J Biochem Cell Biol ; 83: 84-96, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27988363

RESUMO

We investigated the role of the intracellular energy-sensing AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway in the in vitro antiglioma effect of the cyclooxygenase (COX) inhibitor indomethacin. Indomethacin was more potent than COX inhibitors diclofenac, naproxen, and ketoprofen in reducing the viability of U251 human glioma cells. Antiglioma effect of the drug was associated with p21 increase and G2M cell cycle arrest, as well as with oxidative stress, mitochondrial depolarization, caspase activation, and the induction of apoptosis. Indomethacin increased the phosphorylation of AMPK and its targets Raptor and acetyl-CoA carboxylase (ACC), and reduced the phosphorylation of mTOR and mTOR complex 1 (mTORC1) substrates p70S6 kinase and PRAS40 (Ser183). AMPK knockdown by RNA interference, as well as the treatment with the mTORC1 activator leucine, prevented indomethacin-mediated mTORC1 inhibition and cytotoxic action, while AMPK activators metformin and AICAR mimicked the effects of the drug. AMPK activation by indomethacin correlated with intracellular ATP depletion and increase in AMP/ATP ratio, and was apparently independent of COX inhibition or the increase in intracellular calcium. Finally, the toxicity of indomethacin towards primary human glioma cells was associated with the activation of AMPK/Raptor/ACC and subsequent suppression of mTORC1/S6K. By demonstrating the involvement of AMPK/mTORC1 pathway in the antiglioma action of indomethacin, our results support its further exploration in glioma therapy.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Glioma/tratamento farmacológico , Glioma/metabolismo , Indometacina/farmacologia , Complexos Multiproteicos/antagonistas & inibidores , Serina-Treonina Quinases TOR/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/genética , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase/farmacologia , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Glioma/patologia , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina , Modelos Biológicos , Complexos Multiproteicos/metabolismo , RNA Interferente Pequeno/genética , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
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