Browsing by Author "Mardones, Claudia"

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    Constitutive and inducible defense in Eucalyptus determines the feeding host of Gonipterus platensis, denoting specific plant-insect coevolution and a strategy for resistance improvement
    (2022) Campos, Jasna V.; Riquelme, Sebastian; Pecio, Lukas; Guedes, Lubia; Mardones, Claudia; Alzamora, Rosa; Arteaga-Perez, Luis E.; Rubilar, Rafael; Fiehn, Oliver; Perez, Andy J.
    Defoliation caused by Gonipterus platensis on Eucalyptus seriously impacts tree growth rate and forest production. The weevil's feeding preference has sometimes limited which species of Eucalyptus to plant, although the plant's metabolic features that govern such choice still need to be uncovered. We used metabolomics to reveal the chemical traits mediating this interaction, focusing on a model formed by two Eucalyptus species with markedly different susceptibility, E. globulus (susceptible), and E. nitens (resistant). Our results suggest that the insect's feeding preference strongly depends on the Eucalyptus species' constitutive metabolome, especially on the stilbenes and hydrolysable tannins accumulation. The susceptible E. globulus could not produce such classes of metabolite either constitutively or after herbivory, which indicated an apparent lack of critical enzymes for biosynthesis of these substances, such as stilbene synthase (STS) and gallate 1-beta-glucosyltransferase. On the other hand, it seems that no matter how toxic the systemic defense induced in E. globulus after herbivory could be to an insect, counteradaptations, apparently evolved by the weevil, may efficiently detoxify them. This may result from plant-insect coevolution, given their common geographical origin. Inter-specific hybridizations between E. nitens and E. globulus have adapted hybrid species better to low temperatures and frost conditions, consequently being propagated for plantations in temperate regions. Thus, this research lays the groundwork for selecting the best parent genotypes and obtained hybrids, aiming to warrant the transfer of key resistance traits to progenies as an attractive strategy for future breeding programs.
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    Sirex noctilio infestation led to inevitable pine death despite activating pathways involved in tolerance
    (2022) Riquelme, Sebastian; Campos, Jasna, V; Pecio, Lukasz; Alzamora, Rosa; Mardones, Claudia; Simonet, Ana M.; Arteaga-Perez, Luis E.; Rubilar, Rafael; Fiehn, Oliver; Perez, Andy J.
    Defense-related metabolome traits in pine species after infestation by Sirex noctilio are largely unknown, despite, in most cases, trees being overwhelmed. Using LC-MS-based untargeted metabolomics, we revealed the systemic metabolic changes induced by this insect in 14-year-old Pinus radiata trees, the most affected species worldwide. An immediate metabolome alteration was expressed in needles after infestation, including the up-regulation of flavonols, flavan-3-ols, oxyneolignans, auxins, proline, and tryptophan, among others. The flavan-3-ols (catechin and procyanidin B1) suggested a rapidly induced photoprotection mechanism aided by diverting proline as an alternative substrate for respiration to compensate for the progressive chlorosis that degrades photosystems. Meanwhile, glutathione, glutamate, and ascorbate levels significantly dropped in needles, which may indicate the critical oxidative stress that trees had to face since the onset of the infestation. They were not fully replenished after long-term infestation, and redox homeostasis was probably not achieved, compromising tree survival. Nevertheless, a huge auxins overexpression detected in needles throughout the infestation may reflect tolerance against the premature senescence caused by the woodwasp venom. In contrast, the metabolome of wood tissues remained initially unchanged, although it seems to collapse after three months. Overall, the metabolomics strategy adopted in this work evidenced its usefulness in uncovering the fundamental roles of plants' chemical defense that govern interactions with specific stressors.
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    Multivariate Bayesian discrimination for varietal authentication of Chilean red wine
    (TAYLOR & FRANCIS LTD, 2011) Gutierrez, Luis; Quintana, Fernando A.; von Baer, Dietrich; Mardones, Claudia
    The process through which food or beverages is verified as complying with its label description is called food authentication. We propose to treat the authentication process as a classification problem. We consider multivariate observations and propose a multivariate Bayesian classifier that extends results from the univariate linear mixed model to the multivariate case. The model allows for correlation between wine samples from the same valley. We apply the proposed model to concentration measurements of nine chemical compounds named anthocyanins in 399 samples of Chilean red wines of the varieties Merlot, Carmenere and Cabernet Sauvignon, vintages 2001-2004. We find satisfactory results, with a misclassification error rate based on a leave-one-out cross-validation approach of about 4%. The multivariate extension can be generally applied to authentication of food and beverages, where it is common to have several dependent measurements per sample unit, and it would not be appropriate to treat these as independent univariate versions of a common model.
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    Prototypes of nutraceutical products from microparticles loaded with stilbenes extracted from grape cane
    (2022) Avendano-Godoy, Javier; Ortega, Elisa; Urrutia, Manuel; Escobar-Avello, Danilo; Luengo, Javiana; von Baer, Dietrich; Mardones, Claudia; Gomez-Gaete, Carolina
    Grape canes (Vitis vinifera L.) are an important source of bioactive stilbenes, but they are considered a pruning residue. Despite the potential advantages for human health, the low aqueous solubility and stability limits their usage in commercial goods.This research aimed to improve knowledge about the solubility and stability of the main stilbenes present in important residues of the wine industry, such as grape canes (V. vinifera L. cv. Pinot Noir), through the formation of inclusion complexes with cyclodextrins (CDs) and subsequent polymeric microencapsulation.The formation of inclusion complexes between stilbenes presents in grape cane extracts and 15 mM hydroxypropyl-fl-cyclodextrin (HP-fl-CD) increased the aqueous solubility of (E)-resveratrol, (E)-e-viniferin and (E)-piceatannol by 2.8, 5.4 and 1.9 times, respectively. The microencapsulation (by spray drying) of the inclusion complexes using maltodextrin (MD) (10% w/v) allowed us to improve the stability of the stilbenes, obtaining a retention percentage of 81.9 +/- 2.2% after 60 min of UV irradiation (254 nm). The lower size microparticles (MPs) formulation was 10.9 +/- 0.9 mu m and had a stilbene loading of 0.61 +/- 0.01 mg/100 mg of MPs. The prototype tablets and capsules made from the MPs presented suitable characteristics for their eventual use.The microencapsulation of inclusion complexes between stilbenes presents in grape cane extracts and HP-fl-CD, using MD as a matrix component, is useful to increase the solubility and stability of stilbenes. The prepared MPs can be used for the development of nutraceutical products.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.