1,720,985 research outputs found
Understanding of grapevine communication mediated by volatile organic compounds against downy mildew using a metabolomics approach
Full text linkPlants can produce a wide variety of volatile organic compounds (VOCs), which play a crucial role in the interaction with other organisms and the regulation of plant responses against stresses. Different modes of action against phytopathogens have been attributed to VOCs, such as induction of plant resistance and direct inhibition of pathogen growth. In particular, the amount of some VOCs was higher in resistant than in susceptible grapevine genotypes upon Plasmopara viticola inoculation, indicating their possible involvement in resistance mechanisms against this pathogen. This work aims at identifying the metabolic response of VOC-treated grapevine leaves and the potential activation VOC-mediated resistance mechanisms. Susceptible grapevine leaf disks were treated with pure VOCs produced by resistant genotypes, or with water as control. Functional analyses confirmed that two VOCs (one C13-norisoprenoid and one pyrone) reduced the disease severity on downy mildew on susceptible leaf disks and leaf disks were collected at two time points (one and six days after inoculation) from VOC-treated and control samples. transcriptional analyses revealed an increased expression level of defence-related gene, such as hypersensitivity-related, osmotin, chitinase and pathogenesis-related genes. Metabolomic analyses will be applied to clarify the mechanisms of action of VOCs and the response of VOC-treated leaves using ultra-high pressure liquid chromatography-high resolution-quadrupole-time of flight-mass spectrometry (UHPLC-Q-TOF-MS) analysis
Understanding of grapevine mechanisms mediated by volatile organic compounds against downy mildew using a metabolomics approach
Full text linkPlants can produce a wide variety of volatile organic compounds (VOCs), which can play a crucial role in the regulation of plant responses against stress. Different modes of action against phytopathogens have been attributed to VOCs, such as induction of plant resistance and direct inhibition of pathogen growth. In particular, the amount of some VOCs was higher in resistant than in susceptible grapevine genotypes upon Plasmopara viticola inoculation, indicating their possible involvement in resistance mechanisms against this pathogen. This work aims at identifying the metabolic response of VOC-treated grapevine leaves and the potential activation of VOC-mediated resistance mechanisms using a metabolomics approach. Functional analysis confirmed that a sesquiterpene reduced downy mildew severity on susceptible grapevine leaf disks. An untargeted metabolomics approach was applied using ultra-high pressure liquid chromatography-high resolution-quadrupole-time of flight-mass spectrometry (UHPLC-Q-TOF-MS) analysis of leaf disks at one and six days post inoculation. Principal component analysis applied on the features (specified by retention time and mass to charge ratio), discriminated samples according to VOC treatment and time point, indicating global metabolite changes after VOC treatment. Features with significant changes in abundance were identified according to the Kruskal-Wallis test (P ≤ 0.05) and a fold-change higher than two in at least one comparison. The selected features will be annotated comparing retention times and mass spectra accuracy with different databases. These results will help to improve the knowledge on plant defence mechanisms activated by VOCs, in order to identify active compounds for plant protection against pathogens
Metabolomic approach for understanding grapevine communication mediated by volatile organic compounds
No full textPlants can produce a wide variety of volatile organic compounds (VOCs), which play a crucial role in the interaction with other organisms and the regulation of plant responses against stresses. Different modes of action against phytopathogens have been attributed to biogenic VOCs, such as induction of plant resistance and direct inhibition of pathogen growth. In particular, the amount of some biogenic VOCs was higher in downy mildew-resistant compared with susceptible grapevine genotypes upon inoculation with Plasmopara viticola. Thus, biogenic VOCs indicate a possible involvement in the grapevine resistance mechanisms against this pathogen. This work aims at identifying the metabolic response of VOC-treated grapevine leaves and the potential activation of VOC-mediated resistance mechanisms. Susceptible grapevine leaf disks were treated with pure biogenic VOCs or with water as control. Functional and transcriptional analyses confirmed that two VOCs reduced downy mildew severity and increased expression level of defense-related genes in susceptible leaf disks. An untargeted metabolomics approach was applied using ultra-high pressure liquid chromatography-high resolution-quadrupole-time of flight-mass spectrometry (UHPLC-Q-TOF-MS) analysis to clarify the mechanisms of action of VOCs and the response of VOC-treated leaf disks. Preliminary results revealed marked differences occurred between VOCs-treated and control samples, indicating a clear metabolic response of receiver plants in response of biogenic VOCs. Principal component analysis (PCA) discriminated samples according to the time point and VOC treatment. Further data analyses will help to improve knowledge on the plant defense mechanisms activated by biogenic VOC
Untargeted Metabolomics approach to understand grapevine communication mediated by volatile organic compounds against downy mildew
Full text linkVolatile organic compounds (VOCs) play crucial roles in the communication of plants with other organisms and are mediators of plant defense against pathogens. The objective of this work is to understand the mechanism of grapevine communications mediated by VOCs against grapevine downy mildew (caused by Plasmopara viticola), using an untargeted metabolomics approach
Candidate gene transcriptional signature unravels the reprogramming occurring in the peel of apple fruit of ‘Granny smith’ during postharvest storage
Full text linkAfter harvest fruit are stored to preserve the quality features established during the on-tree development and maturation, ensuring thus a continuous availability of fresh fruit on the market. For certain fruit species like apple, storage can last for almost a year, especially when coupled with several strategies, such as the reduction of the oxygen concentration or the application of ethylene competitor molecules, like 1-methylcyclopropene (1-MCP). To guarantee the maintenance of the highest quality, the monitoring of the physiological processes ongoing during the postharvest ripening is compelling. For this purpose, 16 genes belonging to key fruit ripening pathways, such as the ethylene and the sugar/fermentation metabolism, have been chosen as potential markers for the molecular characterization of the major changes occurring in the fruit during storage. Among these genes, ACS, PPO, PG1, RAP2-like, and ADH exhibited the most significant differential expression across the various samples. Based on the transcriptional pattern, this set of genes constitutes a valuable molecular tool for a precise and reliable RNA-based monitoring of the postharvest ripening progression and fermentation process in apples. PPO, together with S6PDH, were furthermore employed to inspect the onset of the superficial scald in apple and resulted to correlate with the evaluation of the incidence of this disorder and the accumulation of the sugar alcohol sorbitol, known to play important protecting roles to chilling injuries. The assessment of the transcriptional signature of these elements can facilitate the development of gene expression markers suitable for a more informed investigation of the physiological progression of the postharvest ripening in apples, ultimately leading to the promotion of high-quality stored apples, extending storage time while minimizing postharvest disorders and fruit los
Volatile 2‐phenylethanol and β‐cyclocitral trigger defense‐related transcriptional and metabolic changes in grapevine leaves against downy mildew
Full text linkVolatile organic compounds (VOCs) are produced by grapevine leaves in response to phytopathogen infection. In particular, 2-phenylethanol and β-cyclocitral were triggered by Plasmopara viticola inoculation in downy mildew-resistant genotypes, but no information is available on their involvement in plant resistance induction. This study aimed to clarify transcriptional and metabolic changes associated with VOC-induced resistance activated by 2-phenylethanol and β-cyclocitral treatments against P. viticola. Both VOCs decreased downy mildew severity on grapevine leaf disks by complex reprogramming of the grapevine transcriptome at 1 and 6 days post inoculation. RNA-Seq analysis showed the modulation of transcripts related to defense (chitinases, defense-related proteins, and pathogenesis-related proteins), oxidative stress (glutathione S-transferases and peroxidases), secondary metabolism (nitrilases, stilbene synthases, and terpene synthases), signal transduction (e.g., kinases, receptor kinases, and calmodulins), and transcription (bHLH, ERF, MYB, NAC, and WRKY transcription factors) in leaf disks treated with 2-phenylethanol and β-cyclocitral. VOC treatments also caused changes in the leaf metabolome, and pathway analysis of metabolic features with significant changes in abundance in 2-phenylethanol- and β-cyclocitral-treated leaf disks revealed the reprogramming of amino acid, carbohydrate, flavonoid, phenylpropanoid, and terpenoid metabolism. In particular, compounds with increases in abundance belonged to putative carbohydrates, carboxylic acids, and phenylpropanoids in 2-phenylethanol-treated samples, or carboxylic acids and terpenoids in β-cyclocitral-treated samples, including molecules possibly associated with plant defense against pathogens, such as 3-dehydroquinic acid, 4-thujanol, aromadendrin, camphor, p-coumaryl alcohol, and perillaldehyde. Correlation analysis between transcriptomic and metabolomic data indicated that 2-phenylethanol and β-cyclocitral act as resistance inducers against downy mildew in grapevin
Biogenic volatile organic compounds in the grapevine response to pathogens, beneficial microorganisms, resistance inducers and abiotic factors
No full textVolatile organic compounds (VOCs) synthesis is triggered in plants in response to external stimuli and can migrate to distal tissues and neighbouring receivers. Although grapevine VOCs responsible for wine aroma and plant-insect communications are well characterised, functional properties of VOCs produced in responses to phytopathogens, beneficial microorganisms, resistance inducers and abiotic factors are less studied. In this review, we focused on the emission patterns and potential biological functions of VOCs produced by grapevines in response to biotic and abiotic stimuli. Specific grapevine VOCs are emitted in response to the exogenous stimulus, suggesting their precise involvement in plant defence response. VOCs with inhibitory activities against pathogens and responsible for plant resistance induction are reported and some of them can also be used as biomarkers of grapevine resistance. Likewise, VOCs produced in response to beneficial microorganisms and environmental factors are possible mediators of grapevine-microbe communications and abiotic stress tolerance. Although further functional studies may improve our knowledge, the existing literature suggest that VOCs have an underestimated potential application as pathogen inhibitors, resistance inducers against biotic or abiotic stresses, signalling molecules, membrane stabilisers and modulators of reactive oxygen species. VOC patterns could also be used to screen for resistant traits or to monitor the plant physiological statu
Mead fermentation monitoring by proton transfer reaction mass spectrometry and medium infrared probe
No full textMead is a traditional alcoholic beverage similar to wine, but obtained by the fermentation of a diluted solution of honey. The rate of fermentation is generally monitored by the measurement of a set of physicochemical variables such as pH, titratable acidity, Brix degrees, sugars and ethanol concentration. This work aims at developing a new monitoring method for alcoholic fermentations that is based on two on-line approaches: a proton transfer reaction mass spectrometry (PTR-MS) and a fibre optic coupled attenuated total reflection (FTIR-ATR) spectroscopy. Microfermentations are performed on 100 mL musts in isothermal conditions at 20 °C. Musts consist on diluted honey solutions (24 Bx) with pollen (0.4 % w/v) and yeast (Saccharomyces cerevisiae subsp. bayanus). The effect of flavour enhancers [chilli (Capsicum annuum), clove (Eugenia caryophyllata) and a mixture of both] on the rate of fermentation was also evaluated. The results show that clove inhibits fermentation, whereas chilli increases the rate of fermentation. PTR-MS and FTIR-ATR are simple, fast and nondestructive techniques able to monitor the fermentation process without the need of sample preparation, extraction or pre-concentration steps
Improving spectral similarity and molecular network reliability through noise signal filtering in MS/MS spectras
Full text linkIn mass spectrometry, fragmentation spectra play a central role in compound identification. However, noise in MS/MS spectra can significantly impact similarity scores and molecular network (MN) reliability, leading to inaccurate compound annotation in untargeted metabolomics. This work investigates the influence of noise on MS/MS similarity scores and molecular network structure. Noise elimination increased similarity scores for homologous spectra, enhancing match affordability. In MNs, effective noise management improved network structure, resulting in more interpretable networks with fewer edges and enhanced clustering, decreasing false-positive connections. To quantitatively assess these improvements, a minimum spanning tree (MST) analysis was performed, revealing denser regions in the denoised MNs. An increasing cutoff of noise threshold can lead to an overlay between two or more different compound spectra. A data-specific workflow was developed to identify the optimal threshold for denoising, balancing spectra quality and network integrity during noise elimination, by incorporating statistics calculated on the distribution of the MST distances and the number of fragment ions, which could be explained by an in-silico fragmentation algorithm. Finally, a faster-tailored denoising method, based solely on the intensity of individual spectral ions, demonstrated performance comparable to the previously cited fixed threshold approache
Comparative untargeted metabolomic analysis of Alternaria strains to uncover phytotoxic compounds
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