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1.
Int J Mol Sci ; 22(3)2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33540857

RESUMO

Yellow peel will adversely affect the appearance quality of cucumber fruit, but the metabolites and the molecular mechanism of pigment accumulation in cucumber peel remain unclear. Flavonoid metabolome and transcriptome analyses were carried out on the young peel and old peel of the color mutant L19 and the near-isogenic line L14. The results showed that there were 165 differential flavonoid metabolites in the old peel between L14 and L19. The total content of representative flavonoid metabolites in the old peel of L14 was 95 times that of L19, and 35 times that of young peel of L14, respectively. This might explain the difference of pigment accumulation in yellow peel. Furthermore, transcriptome analysis showed that there were 3396 and 1115 differentially expressed genes in the yellow color difference group (Young L14 vs. Old L14 and Old L14 vs. Old L19), respectively. These differentially expressed genes were significantly enriched in the MAPK signaling pathway-plant, plant-pathogen interaction, flavonoid biosynthesis and cutin, suberine and wax biosynthesis pathways. By analyzing the correlation between differential metabolites and differentially expressed genes, six candidate genes related to the synthesis of glycitein, kaempferol and homoeriodictyol are potentially important. In addition, four key transcription factors that belong to R2R3-MYB, bHLH51 and WRKY23 might be the major drivers of transcriptional changes in the peel between L14 and L19. Then, the expression patterns of these important genes were confirmed by qRT-PCR. These results suggested that the biosynthesis pathway of homoeriodictyol was a novel way to affect the yellowing of cucumber peel. Together, the results of this study provide a research basis for the biosynthesis and regulation of flavonoids in cucumber peel and form a significant step towards identifying the molecular mechanism of cucumber peel yellowing.


Assuntos
Cucumis sativus/metabolismo , Frutas/metabolismo , Genes de Plantas , Metaboloma , Pigmentos Biológicos/metabolismo , Epiderme Vegetal/metabolismo , Transcriptoma , Carotenoides/metabolismo , Cucumis sativus/genética , DNA de Plantas/genética , Flavonas/metabolismo , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Sistema de Sinalização das MAP Quinases , Pigmentação , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Fatores de Transcrição/metabolismo
2.
Ecotoxicol Environ Saf ; 208: 111654, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396168

RESUMO

Salicylic acid (SA) is an important signal molecule, regulating oxidative stress response in plants. In this study, we evaluated the influences of SA (1 mg L-1, 10 mg L-1 and 50 mg L-1) on the accumulation of clothianidin (CLO), dinotefuran (DFN) and difenoconazole (DFZ) (5 mg L-1) and pesticide-induced (CLO-10 mg L-1, DFN-20 mg L-1, and DFZ-10 mg L-1) oxidative stress in cucumber plants. Exogenous SA at 10 mg L-1 significantly reduced the half-lives of three pesticides in nutrient solution and prevented the accumulation of pesticides in roots and leaves. And the role of SA in reducing residues was related to the major accumulation sites of pesticides. By calculating the root concentration factor (RCF) and translocation factor (TF), we found that SA at 10 mg L-1 reduced the ability of roots to absorb pesticides and enhanced the translocation ability from roots to leaves. Roots exposed to high concentrations of three pesticides could reduce biomass, low chlorophyll content, increase the accumulation of reactive oxygen species (ROS) and proline, promote lipid peroxidation, and alter the activities of a range of antioxidant enzymes, respectively. Exogenous SA at low concentrations (1 mg L-1 and 10 mg L-1) significantly mitigated these negative effects. Hence, application of exogenous SA at 10 mg L-1 could effectively alleviate the accumulation of pesticides and induce stress tolerance in cucumber planting systems.


Assuntos
Cucumis sativus/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Praguicidas/metabolismo , Ácido Salicílico/farmacologia , Antioxidantes/metabolismo , Clorofila/metabolismo , Cucumis sativus/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Praguicidas/toxicidade , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo
3.
Food Chem ; 342: 128299, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33508901

RESUMO

Manganese-doped zinc sulfide quantum dots (Mn-ZnS QDs) are promising candidates for multi-channel sensing analysis due to their multi-dimensional optical properties. In this study, we integrated amino-silane and ionic liquid co-modified Mn-ZnS QDs and covalent organic frameworks (COFs) into optosensing nanoparticles to provide triple-dimensional optical response signals and combined them with chemometrics for the analysis of multiple pesticide residues. Through the exploration and optimization of a series of conditions, fluorescence, room temperature phosphorescence, and ultraviolet-visible combined with chemometrics were used for the discrimination and recognition of multiple pesticide residues in fruits and vegetables. The ionic liquid of 1-vinyl-3-ethylimidazolium tetrafluoroborate was used to modify Mn-ZnS QDs to improve the optical response and enrichment of pesticide adsorption sites, which were also synergistically enhanced by the COF support. This is a potential method to discriminate pesticides efficiently and enables fast and reliable analysis of pesticides in the agricultural and food industries.


Assuntos
Líquidos Iônicos/química , Estruturas Metalorgânicas/química , Resíduos de Praguicidas/análise , Pontos Quânticos/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Cucumis sativus/química , Cucumis sativus/metabolismo , Análise Discriminante , Concentração de Íons de Hidrogênio , Malus/química , Malus/metabolismo , Manganês/química , Análise de Componente Principal , Sulfetos/química , Compostos de Zinco/química
4.
PLoS One ; 15(5): e0232765, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365099

RESUMO

The water-soluble fullerenols are novel carbon-based nanomaterials with unique properties, which afford them with wide agricultural applications. Iron (Fe) deficiency is the most common and widespread nutrition disorder affecting plants. Foliar Fe treatments of plants have been carried out with solutions devoid of fullerenol. In this study, the role of fullerenol [C60(OH)22-24] in alleviation of Fe deficiency in Cucumis sativus (a Strategy I plant) via foliar fertilization was investigated. Cucumber plants were grown hydroponically, either with (Fe) or in Fe-free (-Fe) nutrient solution. The following foliar spray treatments were applied: fullerenol at final concentrations of 1 (F1) and 10 (F10) mg L-1; Fe(II)SO4·7H2O; Fe(II)-EDTA (ethylenediaminetetraacetic acid); and Fe(II)-F1 and Fe(II)-F10. The best used compound was a combination of Fe(II)-sulfate with fullerenol, especially Fe-F1. The addition of fullerenol to Fe(II)-sulfate solutions significantly increased leaf-active Fe (extracted by an Fe(II) chelator) and re-greening at the site of application. The fullerenol-induced mutual influences did not appear when fullerenol was sprayed alone, suggesting a beneficial role of Fe(II)-fullerenol interactions in the penetration of Fe(II) in the leaves and re-greening under Fe-limited conditions. The results are of importance to enhancing the potential of foliar Fe fertilization as the commonly used strategy for ameliorating Fe deficiency and improving crop yield and quality.


Assuntos
Cucumis sativus/metabolismo , Fulerenos/farmacologia , Ferro/deficiência , Folhas de Planta/metabolismo , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Clorofila/metabolismo , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/crescimento & desenvolvimento , Hidroponia , Tamanho da Partícula , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Espectrofotometria Infravermelho , Eletricidade Estática
5.
Plant Mol Biol ; 103(4-5): 489-505, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32306368

RESUMO

KEY MESSAGE: Cucumber plants adapt their transcriptome and metabolome as result of spider mite infestation with opposite consequences for direct and indirect defences in two genotypes. Plants respond to arthropod attack with the rearrangement of their transcriptome which lead to subsequent phenotypic changes in the plants' metabolome. Here, we analysed transcriptomic and metabolite responses of two cucumber (Cucumis sativus) genotypes to chelicerate spider mites (Tetranychus urticae) during the first 3 days of infestation. Genes associated with the metabolism of jasmonates, phenylpropanoids, terpenoids and L-phenylalanine were most strongly upregulated. Also, genes involved in the biosynthesis of precursors for indirect defence-related terpenoids were upregulated while those involved in the biosynthesis of direct defence-related cucurbitacin C were downregulated. Consistent with the observed transcriptional changes, terpenoid emission increased and cucurbitacin C content decreased during early spider-mite herbivory. To further study the regulatory network that underlies induced defence to spider mites, differentially expressed genes that encode transcription factors (TFs) were analysed. Correlation analysis of the expression of TF genes with metabolism-associated genes resulted in putative identification of regulators of herbivore-induced terpenoid, green-leaf volatiles and cucurbitacin biosynthesis. Our data provide a global image of the transcriptional changes in cucumber leaves in response to spider-mite herbivory and that of metabolites that are potentially involved in the regulation of induced direct and indirect defences against spider-mite herbivory.


Assuntos
Cucumis sativus/imunologia , Cucumis sativus/metabolismo , Metaboloma , Infestações por Ácaros/imunologia , Infestações por Ácaros/metabolismo , Tetranychidae , Transcriptoma , Animais , Vias Biossintéticas/genética , Cucumis sativus/genética , Cucumis sativus/parasitologia , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genoma de Planta , Genótipo , Herbivoria , Oxilipinas/metabolismo , Fenilalanina/metabolismo , Fenilpropionatos/metabolismo , Doenças das Plantas , Folhas de Planta/metabolismo , Metabolismo Secundário/genética , Terpenos/metabolismo , Fatores de Transcrição/genética , Triterpenos/metabolismo , Compostos Orgânicos Voláteis/metabolismo
6.
Plant Physiol Biochem ; 150: 140-150, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32142987

RESUMO

Peptide: N-glycanase (PNGase; EC 3.5.1.52) is a deglycosylation enzyme that is responsible for deglycosylating misfolded glycoproteins in the endoplasmic reticulum. However, the role of PNGase in plants is largely unknown. Here, we cloned and characterized the function of peptide: N-glycanase (CsPNG1) from cucumber. The amino acid encoded by CsPNG1 gene contained a typical transglutaminase (TGase) catalytic triad domain and belonged to the "TGase superfamily". Subcellular localization showed that CsPNG1 was located in the cell membrane and nucleus. Promoter sequence analysis and qPCR tests showed that CsPNG1 could respond to a variety of abiotic stresses and hormone treatments. Yeast one-hybrid assays revealed the interaction between the transcription factor CsGT-3b and CsPNG1 promoter. Importantly, overexpression of CsPNG1 in tobacco increased the tolerance to salt stress of transgenic plants. In addition, CsPNG1 interacted with CsRAD23 family proteins and the C-terminal UBA domain of CsRAD23 protein was responsible for binding to CsPNG1, indicating that CsPNG1 was involved in the ER-associated degradation pathway (ERAD). Taken together, our study demonstrated that CsPNG1 plays a positive role in improving plant salt tolerance, and these findings might provide a basis for further functional analysis of CsPNG1 genes in abiotic stress and ERAD.


Assuntos
Cucumis sativus , Proteínas de Plantas , Estresse Fisiológico , Cucumis sativus/genética , Cucumis sativus/metabolismo , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica de Plantas , Glicoproteínas , Peptídeo-N4-(N-acetil-beta-glucosaminil) Asparagina Amidase/genética , Peptídeo-N4-(N-acetil-beta-glucosaminil) Asparagina Amidase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estresse Fisiológico/genética , Tabaco/genética
7.
Plant Sci ; 293: 110431, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081271

RESUMO

Iron (Fe) is an essential micronutrient for plant life and development. However, in soil, Fe bioavailability is often limited and variable in space and time, thus different regions of the same root system might be exposed to different nutrient provisions. Few studies showed that the response to variable Fe provision is controlled at local and systemic levels, albeit the identity of the signals involved is still elusive. Iron itself was suggested as local mediator, whilst hormones were proposed for the long-distance signalling pathway. Therefore, the aim of this work was to assess whether Fe, when localized in a restricted area of the root system, might be involved in both local and systemic signaling. The combination of resupply experiments in a split-root system, the use of 57Fe isotope and chemical imaging techniques allowed tracing Fe movement within cucumber plants. Soon after the resupply, Fe is distributed to the whole plant, likely to overcome a minimum Fe concentration threshold aimed at repressing the deficiency response. Iron was then preferentially translocated to leaves and, only afterwards, the root system was completely resupplied. Collectively, these observations might thus highlight a root-to-shoot-to-root Fe translocation route in cucumber plants grown on a patchy nutrient substrate.


Assuntos
Transporte Biológico/fisiologia , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/metabolismo , Ferro/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Cálcio/metabolismo , Ferro/deficiência , Ferro/farmacologia , Isótopos , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Brotos de Planta/efeitos dos fármacos , Solo/química , Zinco/metabolismo
8.
J Plant Physiol ; 246-247: 153129, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32050138

RESUMO

Micronutrients provide a potentially interesting alternative to fungicides for the protection of crops against fungal pathogens. Here we studied the effect of foliar-applied manganese (Mn) in the form of MnSO4 on severity of anthracnose disease, caused by Colletotrichum lagenarium in cucumber (Cucumis sativus L.) plant. The study was done aimed to characterize the optimum dose and application time of Mn fertilizer on disease suppression as well as to identify the defense mechanisms by which Mn-treated plants resist to fungal disease. In preliminary tests, Mn was applied at different concentrations (1.8, 4.5 and 7.2 mM) and various time points (three days before or two hours before inoculation, or three days after inoculation). Results showed that application of Mn either before or after inoculation suppressed the fungal infection in leaves and cotyledons, with a higher efficiency when applied three days prior to inoculation. However, all applied concentrations of Mn equally reduced the disease severity. Mn treatment in the absence of the pathogen promoted lignification and reactive oxygen species (ROS) accumulation. Also, pre-inoculation Mn treatment enhanced pathogen-induced lignification, callose or ROS production and reduced pathogen-induced cell death. The increase of lignin, callose and ROS induction by Mn application were 34, 30 and 31 % compared to control, respectively. Together, the results suggested the effectiveness of Mn treatments on anthracnose alleviation in cucumber plants. The findings here have a practical importance in plant physiology studies to identify the resistance-relevant mechanisms to pathogens and in sustainable agriculture to control the fungal diseases by a safe method.


Assuntos
Colletotrichum/fisiologia , Cucumis sativus/efeitos dos fármacos , Manganês/metabolismo , Doenças das Plantas/microbiologia , Cucumis sativus/metabolismo , Cucumis sativus/microbiologia , Resistência à Doença/efeitos dos fármacos , Manganês/administração & dosagem , Micronutrientes/administração & dosagem , Micronutrientes/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
9.
Int J Mol Sci ; 21(3)2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32033119

RESUMO

Treatment by volatile plant hormone methyl jasmonate (MeJA) leads to release of methanol and volatiles of lipoxygenase pathway (LOX volatiles) in a dose-dependent manner, but how the dose dependence is affected by stomatal openness is poorly known. We studied the rapid (0-60 min after treatment) response of stomatal conductance (Gs), net assimilation rate (A), and LOX and methanol emissions to varying MeJA concentrations (0.2-50 mM) in cucumber (Cucumis sativus) leaves with partly open stomata and in leaves with reduced Gs due to drought and darkness. Exposure to MeJA led to initial opening of stomata due to an osmotic shock, followed by MeJA concentration-dependent reduction in Gs, whereas A initially decreased, followed by recovery for lower MeJA concentrations and time-dependent decline for higher MeJA concentrations. Methanol and LOX emissions were elicited in a MeJA concentration-dependent manner, whereas the peak methanol emissions (15-20 min after MeJA application) preceded LOX emissions (20-60 min after application). Furthermore, peak methanol emissions occurred earlier in treatments with higher MeJA concentration, while the opposite was observed for LOX emissions. This difference reflected the circumstance where the rise of methanol release partly coincided with MeJA-dependent stomatal opening, while stronger stomatal closure at higher MeJA concentrations progressively delayed peak LOX emissions. We further observed that drought-dependent reduction in Gs ameliorated MeJA effects on foliage physiological characteristics, underscoring that MeJA primarily penetrates through the stomata. However, despite reduced Gs, dark pretreatment amplified stress-volatile release upon MeJA treatment, suggesting that increased leaf oxidative status due to sudden illumination can potentiate the MeJA response. Taken together, these results collectively demonstrate that the MeJA dose response of volatile emission is controlled by stomata that alter MeJA uptake and volatile release kinetics and by leaf oxidative status in a complex manner.


Assuntos
Acetatos/farmacologia , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/fisiologia , Ciclopentanos/farmacologia , Oxilipinas/farmacologia , Folhas de Planta/fisiologia , Estômatos de Plantas/fisiologia , Estresse Fisiológico/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Cucumis sativus/metabolismo , Metanol/farmacologia , Osmose/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/metabolismo , Estresse Fisiológico/efeitos dos fármacos
10.
Environ Pollut ; 259: 113957, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32023799

RESUMO

Bisphenol A (BPA) is an emerging organic pollutant, widely distributed in environment. Plants can uptake and metabolize BPA, but BPA accumulation induces phytotoxicity. In this study, we administered dopamine, a kind of catecholamines with strong antioxidative potential, to unveil its role in cucumber tolerance to BPA stress. The results showed that exposure to BPA (20 mg L-1) for 21 days significantly reduced growth and biomass accumulation in cucumber seedlings as revealed by decreased lengths and dry weights of shoots and roots. While BPA exposure decreased the chlorophyll content, cell viability and root activity, it remarkably increased reactive oxygen species (ROS) accumulation, electrolyte leakage and malondialdehyde (MDA) content, suggesting that BPA induced oxidative stress in cucumber. However, exogenous dopamine application significantly improved the photosynthetic pigment content, root cell viability, growth and biomass accumulation, and decreased the ROS and MDA levels by increasing the activity of antioxidant enzymes under BPA stress. Further analysis revealed that dopamine application significantly increased the glutathione content and the transcripts and activity of glutathione S-transferase under co-administration of dopamine and BPA compared with only BPA treatment. Moreover, dopamine decreased the BPA content in both leaves and roots, suggesting that dopamine promoted BPA metabolism by enhancing the glutathione-dependent detoxification. Our results show that dopamine has a positive role against BPA phytotoxicity and it may reduce the risks-associated with the dietary intake of BPA through consumption of vegetables.


Assuntos
Antioxidantes/metabolismo , Compostos Benzidrílicos/toxicidade , Cucumis sativus/metabolismo , Dopamina/metabolismo , Fenóis/toxicidade , Compostos Benzidrílicos/metabolismo , Estresse Oxidativo , Fenóis/metabolismo , Fotossíntese , Plântula
11.
Ecotoxicol Environ Saf ; 192: 110285, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32035398

RESUMO

Iron deficiency severely affects crop yield and quality. Gamma-aminobutyric acid (GABA) plays a vital role in plant responses to multifarious stresses. However, the role of GABA in Fe deficiency responses and the potential mechanisms remain largely unknown in cucumber. Here, we found that Fe deficiency raised the GABA levels in leaves and roots of cucumber. To probe the role of GABA in Fe deficiency, the seedlings were subjected to five levels of GABA concentrations (0, 5, 10, 20 and 40 mmol L-1) for 7 days under Fe deficiency. The results demonstrated that 20 mM GABA in alleviating the Fe deficiency-induced stress was the most effective. GABA pretreatment reduced the Fe deficiency-induced chlorosis and inhibition of photosynthesis and growth, and significantly enhanced the contents of iron in shoots and roots. Exogenous GABA significantly decreased the pH of nutrient solution and increased ferric-chelate reductase (FCR) activity induced by Fe deficiency and the transcript levels of Fe uptake-related genes HA1, FRO2 and IRT1 in roots. GABA also increased the content of auxin (IAA) and expression of auxin biosynthesis (YUC4), response (IAA1), and transport (PIN1) genes under Fe deficiency. Furthermore, exogenous the auxin transport inhibitor 1-naphthylphthalamic acid (NPA) application abolished the GABA-induced changes in Fe deficiency. In summary, we found that GABA improves tolerance to iron deficiency via an auxin-dependent mechanism in cucumber.


Assuntos
Cucumis sativus/metabolismo , Ácidos Indolacéticos/metabolismo , Ferro/metabolismo , Ácido gama-Aminobutírico/metabolismo , Transporte Biológico , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Plântula/metabolismo , Transdução de Sinais , Ácido gama-Aminobutírico/farmacologia
12.
Int J Mol Sci ; 21(3)2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31991638

RESUMO

Autotoxicity of root exudates is one of the main reasons for consecutive monoculture problem (CMP) in cucumber under greenhouse cultivation. Rootstock grafting may improve the tolerance of cucumber plants to autotoxic stress. To verify the enhanced tolerance to autotoxic stress and illuminate relevant molecular mechanism, a transcriptomic comparative analysis was performed between rootstock grafted (RG) and non-grafted (NG) cucumber plants by a simulation of exogenous cinnamic acid (CA). The present study confirmed that relatively stable plant growth, biomass accumulation, chlorophyll content, and photosynthesis was observed in RG than NG under CA stress. We identified 3647 and 2691 differentially expressed genes (DEGs) in NG and RG cucumber plants when compared to respective control, and gene expression patterns of RNA-seq was confirmed by qRT-PCR. Functional annotations revealed that DEGs response to CA stress were enriched in pathways of plant hormone signal transduction, MAPK signaling pathway, phenylalanine metabolism, and plant-pathogen interaction. Interestingly, the significantly enriched pathway of photosynthesis-related, carbon and nitrogen metabolism only identified in NG, and most of DEGs were down-regulated. However, most of photosynthesis, Calvin cycle, glycolysis, TCA cycle, and nitrogen metabolism-related DEGs exhibited not or slightly down-regulated in RG. In addition, several stress-related transcription factor families of AP2/ERF, bHLH, bZIP, MYB. and NAC were uniquely triggered in the grafted cucumbers. Overall, the results of this study suggest that rootstock grafting improve the tolerance of cucumber plants to autotoxic stress by mediating down-regulation of photosynthesis, carbon, and nitrogen metabolism-related DEGs and activating the function of stress-related transcription factor. The transcriptome dataset provides an extensive sequence resource for further studies of autotoxic mechanism at molecular level.


Assuntos
Cucumis sativus/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Sistema de Sinalização das MAP Quinases , Proteínas de Plantas/biossíntese , Plântula/metabolismo , Estresse Fisiológico , Cucumis sativus/genética , Proteínas de Plantas/genética , Plântula/genética
13.
J Plant Physiol ; 245: 153111, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31926460

RESUMO

Alternative polyadenylation (APA) is a pervasive mechanism for gene regulation in eukaryotes. Stachyose is the main assimilate translocated in the cucumber phloem. Stachyose synthase (CsSTS) catalyzes the last step of stachyose biosynthesis in cucumber leaves and plays a key role in the regulation of assimilate partitioning between source and sink. In this study, three CsSTS mRNAs with the same open reading frame and the 5`untranslated region (UTR), but differing in their 3`UTRs, named CsSTS1 (short), CsSTS2 (medium), and CsSTS3 (long), were identified. Southern blot and sequence analysis of the cucumber genome confirmed that these transcripts are regulated through APA from a single gene. No significant difference of in vitro translation efficiency was found among three mRNAs. However, the relative stabilities of three transcripts varied among different tissues and different leaf development stages of cucumber. CsSTS1 expression in cucumber calli was up-regulated by the raffinose (substrate of CsSTS) and down-regulated by stachyose (product of CsSTS), respectively. In cucumber plants, all three isoforms have considerable expression in non-fruit node leaves. However, in fruit-carrying node leaves, the expression of CsSTS2 and CsSTS3 was severely inhibited and only CsSTS1 was highly expressed, indicating fruit setting has a remarkable effect on the relative expression level of three transcripts. This "fruit setting" effect could be observed until at least 36 h after the fruit was removed from the node. Our results suggest that abundant expression of CsSTS1 is beneficial for stachyose loading in source leaves, and APA is a delicate mechanism for CsSTS to regulate cucumber source-sink balance.


Assuntos
Cucumis sativus/genética , Galactosiltransferases/genética , Oligossacarídeos/metabolismo , Poliadenilação/genética , Regiões 3' não Traduzidas/genética , Metabolismo dos Carboidratos , Cucumis sativus/metabolismo , Frutas/metabolismo , Galactosiltransferases/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Floema/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Isoformas de RNA/metabolismo , Rafinose/metabolismo
14.
Chemosphere ; 243: 125308, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31722261

RESUMO

Cadmium level is continuously increasing in agricultural soils mainly due to anthropogenic activities. Cadmium is one of the most phytotoxic metals in the soils. The present study investigates the possible role of 2-hydroxymelatonin (2-OHMT) in assuagement of Cd-toxicity in cucumber (Cucumis sativus L.) plants. 2-OHMT is an important metabolite produced through interaction of melatonin with oxygenated compounds. Cadmium stress decreased the activity of antioxidant enzymes and polyamines. However, exogenously applied 2-OHMT enhanced plant growth attributes including photosynthetic rate, intercellular CO2 concentration, stomatal conductance and transpiration rate in treated plants. In addition, 2-OHMT induced enhancement of the activity of PAs biosynthesizing enzymes (putrescine, spermidine and spermine) in conjunction with reduction in activity of polyamine oxidase (PAO). 2-OHMT mitigated Cd stress through up-regulation in expression of stress related CS-ERS gene along with the amplified activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in treated seedlings. The improved activity of antioxidant scavengers played central role in reduction of hydrogen peroxide (H2O2), electrolyte leakage (EL) and malondialdehyde (MDA) in plants under Cd stress. Recent findings also advocate the positive correlation between PAs and ethylene, as both possess common precursor. The current study reveals that priming seeds with 2-OHMT reduces Cd-toxicity and makes it possible to cultivate cucumber in Cd-contaminated areas. Future experiments will perhaps help in elucidation of 2-OHMT intervened stress mitigation procedure in C. sativus crop. Furthermore, research with reference to potential of 2-OHMT for stress alleviation in other horticultural and agronomic crops will assist in enhancement of crop productivity.


Assuntos
Cádmio/toxicidade , Cucumis sativus/metabolismo , Melatonina/farmacologia , Plântula/metabolismo , Antioxidantes/metabolismo , Cádmio/metabolismo , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/enzimologia , Melatonina/análogos & derivados , Melatonina/metabolismo , Poliaminas/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Sementes/metabolismo
15.
Food Microbiol ; 86: 103330, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703878

RESUMO

Pickle is a type of mildly lactic acid fermented vegetable and is a traditional dish favored in China, Japan, and Korea. Corruption of spoilage bacteria and accumulation of nitrite during vegetable fermentation are common problems that affect the pickle industry and consumer health. In this work, cucumber juice was used as a vegetable model to study the dominant mesophilic aerobic bacteria (MAB) producing nitrite during pickle fermentation. Virulent phages infecting the dominant MABs combined with Lactobacillus plantarum M6 were used to control these bacteria. Enterobacter cloacae and Pseudomonas fluorescens are the dominant MABs in the fermentation of cucumber juice containing 4% or 8% NaCl, with isolation percentages reaching 30.6% and 23.1%, respectively. Virulent phages PspYZU5415 and EcpYZU01 were isolated using P. fluorescens J5415 and E. cloacae J01 as the host bacteria, respectively. These two phages show a broad host range and strong lytic activity, and their genomes contain no toxins and antibiotic resistance genes. PspYZU5415 and EcpYZU01 were combined into a cocktail (designated as Phage MIX) that effectively inhibits the growth of E. cloacae and P. fluorescens in cucumber juice with different salt concentrations. PhageMIX combined with L. plantarum M6 decreased the counts of P. mendocina and E. cloacae to undetectable levels at 48 h during the fermentation of cucumber juice artificially contaminated with P. mendocina and E. cloacae. In addition, nitrite content increased to 11.3 mg/L at 20 h and then degraded completely at 36 h. By contrast, P. mendocina and E. cloacae remained in the groups without PhageMIX during fermentation (0-48 h). Nitrite content rapidly increased to 65.7 mg/L at 12 h and then decreased to 21.6 mg/L at 48 h in the control group. This study suggests that PhageMIX combined with lactic acid bacterial strains can be used as an ecological starter for controlling the dominant MABs P. mendocina and E. cloacae and for reducing nitrate production during the early stage of pickle fermentation.


Assuntos
Bacteriófagos/fisiologia , Bacteriófagos/patogenicidade , Cucumis sativus/microbiologia , Enterobacter cloacae/virologia , Microbiologia de Alimentos/métodos , Pseudomonas fluorescens/virologia , Verduras/microbiologia , Aerobiose , Bacteriófagos/genética , Bacteriófagos/isolamento & purificação , Cucumis sativus/metabolismo , Enterobacter cloacae/metabolismo , Fermentação , Alimentos e Bebidas Fermentados/microbiologia , Especificidade de Hospedeiro , Lactobacillus plantarum/metabolismo , Nitritos/metabolismo , Pseudomonas fluorescens/metabolismo
16.
Food Chem ; 309: 125659, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31734005

RESUMO

This research aimed to compare the efficiency of five washing solutions (0.9% NaCl, 0.1% NaHCO3, DI water, 0.001% KMnO4, and 0.1% acetic acid) for removing carbaryl residues from cucumber and chili. The vegetables were soaked in 10 mg/L of carbaryl solution for 30 min and then washed for 30 min in one of the five washing solutions and the results compared. Each experiment was performed in triplicate and the amounts of carbaryl residues remaining were determined using high-performance liquid chromatography (HPLC). The results showed that 0.001% KMnO4 was the most effective at removing carbaryl from both vegetables. Washing with 0.001% KMnO4 reduced carbaryl residues to 64% and 28%, respectively, of the original concentrations. Washing with DI water was the least effective method of removing carbaryl residues. Hopefully, the results will encourage further research, into reducing carbaryl contamination by washing with chemical solutions, which will enable producers to reduce pesticide residues.


Assuntos
Carbaril/análise , Cromatografia Líquida de Alta Pressão , Cucumis sativus/química , Resíduos de Praguicidas/análise , Soluções/química , Ácido Acético/química , Carbaril/isolamento & purificação , Cucumis sativus/metabolismo , Contaminação de Alimentos/análise , Resíduos de Praguicidas/isolamento & purificação , Bicarbonato de Sódio/química , Cloreto de Sódio/química , Água/química
17.
Theor Appl Genet ; 133(2): 371-382, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31734868

RESUMO

KEY MESSAGE: Via bulked segregant analysis sequencing combined with linkage mapping, the ist gene responsible for the irregularly striped rind mutation was delimited to a 144-kb region in cucumber. Sequencing and expression analysis identified Csa1G005490 as the candidate gene. The rind appearance of cucumber is one of the most important commercial quality traits. Usually, an immature cucumber fruit has a uniform rind that varies from green to yellow to white among different cultivated varieties. In the present paper, we isolated a novel fruit appearance cucumber mutant, ist, that has an irregularly striped rind pattern. The mutant displayed green irregular stripes on a yellow-green background at the immature fruit stage. Genetic analysis revealed that a single recessive gene, ist, is responsible for this mutation. A BSA (bulked segregant analysis) sequencing approach combined with genetic mapping delimited the ist locus to an interval with a length of 144 kb, and 21 predicted genes were annotated in the region. Based on mutation site screening and expression analysis, two single-nucleotide polymorphisms within the candidate gene, Csa1G005490, were identified as constituting the mutation. Csa1G005490 encodes a polygalacturonase-1 noncatalytic subunit beta protein (PG1ß) known to be involved in fruit softening. The expression of Csa1G005490 was significantly lower in the ist mutant than in the wild type. Transcriptome analysis identified 1796 differentially expressed genes (DEGs) between the ist mutant and wild type. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that these DEGs were enriched mostly in photosynthesis and chlorophyll metabolism pathways. Decreased expression patterns of several chlorophyll synthesis genes in the mutant suggest that ist plays a key role in chlorophyll biosynthesis. These results will provide new insight into the molecular mechanism underlying rind appearance polymorphisms in cucumber.


Assuntos
Cucumis sativus/genética , Frutas/genética , Regulação da Expressão Gênica de Plantas/genética , Poligalacturonase/genética , Clorofila/genética , Clorofila/metabolismo , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Mapeamento Cromossômico , Cucumis sativus/metabolismo , Frutas/metabolismo , Perfilação da Expressão Gênica , Ontologia Genética , Genes de Plantas , Genes Recessivos , Microscopia Eletrônica de Transmissão , Mutação , Fenótipo , Fotossíntese/genética , Proteínas de Plantas/genética , Poligalacturonase/metabolismo , Polimorfismo de Nucleotídeo Único , RNA-Seq , Transdução de Sinais/genética
18.
Appl Microbiol Biotechnol ; 104(2): 785-797, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31813049

RESUMO

Chemotaxis towards root exudates and subsequent biofilm formation are very important for root colonization and for providing the beneficial functions of plant growth-promoting rhizobacteria (PGPRs). In this study, in comparison with other root-secreted compounds, D-galactose in the root exudates of cucumber was found to be a strong chemoattractant at the concentration of 1 µM for Bacillus velezensis SQR9. Chemotaxis assays with methyl-accepting chemotaxis proteins (MCPs) deletion strains demonstrated that McpA was solely responsible for chemotaxis towards D-galactose. Interestingly, D-galactose significantly enhanced the biofilm formation of SQR9 in an McpA-dependent manner. Further experiment showed that D-galactose also enhanced root colonization by SQR9. In addition, the secretion of D-galactose by cucumber roots could be induced by inoculation with SQR9, indicating that D-galactose may be an important signal in the interaction between plant and SQR9. These findings suggested that the root-secreted D-galactose was a signal, the secretion of which was induced by the beneficial bacteria, and which in turn induced colonization of the bacteria.


Assuntos
Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Fatores Quimiotáticos/metabolismo , Cucumis sativus/metabolismo , Galactose/metabolismo , Raízes de Plantas/metabolismo , Bacillus/genética , Biofilmes/crescimento & desenvolvimento , Quimiotaxia , Cucumis sativus/microbiologia , Deleção de Genes , Proteínas Quimiotáticas Aceptoras de Metil/deficiência , Proteínas Quimiotáticas Aceptoras de Metil/metabolismo , Raízes de Plantas/microbiologia
19.
Plant Physiol ; 182(1): 167-184, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31378719

RESUMO

Histone deacetylase (HDAC) proteins participate in diverse and tissue-specific developmental processes by forming various corepressor complexes with different regulatory subunits. An important HDAC machinery hub, the Histone Deacetylase Complex1 (HDC1) protein, participates in multiple protein-protein interactions and regulates organ size in plants. However, the mechanistic basis for this regulation remains unclear. Here, we identified a cucumber (Cucumis sativus) short-fruit mutant (sf2) with a phenotype that includes repressed cell proliferation. SF2 encodes an HDC1 homolog, and its expression is enriched in meristematic tissues, consistent with a role in regulating cell proliferation through the HDAC complex. A weak sf2 allele impairs HDAC targeting to chromatin, resulting in elevated levels of histone acetylation. Genome-wide mapping revealed that SF2 directly targets and promotes histone deacetylation associated with key genes involved in multiple phytohormone pathways and cell cycle regulation, by either directly repressing or activating their expression. We further show that SF2 controls fruit cell proliferation through targeting the biosynthesis and metabolism of cytokinin and polyamines. Our findings reveal a complex regulatory network of fruit cell proliferation mediated by HDC1 and elucidate patterns of HDC1-mediated regulation of gene expression.


Assuntos
Cucumis sativus/metabolismo , Frutas/metabolismo , Histona Desacetilases/metabolismo , Proliferação de Células/genética , Proliferação de Células/fisiologia , Mapeamento Cromossômico/métodos , Cucumis sativus/genética , Frutas/genética , Genoma de Planta/genética , Histona Desacetilases/genética , Processamento de Proteína Pós-Traducional/genética , Processamento de Proteína Pós-Traducional/fisiologia
20.
Plant Physiol Biochem ; 145: 107-113, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31677541

RESUMO

Hexose transporters play many important roles in plant development. However, the role of hexose transporter in secondary cell wall growth has not been reported before. Here, we report that the hexose transporter gene CsHT3 is mainly expressed in cells with secondary cell walls in cucumber. Spatiotemporal expression analysis revealed that the transcript of CsHT3 mainly accumulates in the stem, petiole, tendril, and peduncle, all of which contain high cellulose levels. Immunolocalization results show that CsHT3 is localized at the sclereids in young peduncles, shifts to the phloem fiber cells during peduncle development, and then shifts again to the companion cells when the development of secondary cell walls is almost completed. Carboxyfluoresce unloading experiment indicated that carbohydrate unloading in the phloem follows an apoplastic pathway. Overexpression of CsHT3 in cucumber plant can improve the cellulose content and cell wall thickness of phloem fiber cells in the peduncle. The expression of cellulose synthase genes were increased in the CsHT3 overexpression plants. These results indicated that CsHT3 may play an important role in cellulose synthesis through promoting the expression of cellulose synthase genes.


Assuntos
Cucumis sativus , Frutas , Regulação da Expressão Gênica de Plantas , Proteínas de Transporte de Monossacarídeos , Proteínas de Plantas , Parede Celular , Celulose/genética , Celulose/metabolismo , Cucumis sativus/genética , Cucumis sativus/metabolismo , Frutas/química , Frutas/genética , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Floema , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
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