Facultad de Agronomía e Ingeniería Forestal

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Browsing Facultad de Agronomía e Ingeniería Forestal by browse.metadata.categoriaods "03 Salud y bienestar"

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    Ethylene and Nitrogen crosstalk in Solanum lycopersicum defense against Botrytis cinerea infection
    (2023) Huidobro Marín, Camila; Arce Johnson, Jorge Patricio; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    Durante la respuesta de defensa a Botrytis cinerea, Solanum lycopersicum presenta una menor susceptibilidad mientras exista una mayor biodisponibilidad de nitrógeno. El mecanismo por el que esto ocurre no se encuentra dilucidado. Cabe destacar que en otras especies como Arabidopsis thaliana, se da el caso contrario. En este trabajo, se estudió una posible diafonía entre etileno y nitrógeno mediando la defensa en plantas de tomate infectadas con botrytis. Para abordar este tema, se realizaron tratamientos con etileno exógeno y un inhibidor de esta hormona en plantas crecidas en concentraciones contrastantes de nitrógeno e infectadas con botrytis. Se evaluó el tamaño de lesión durante la progresión de la enfermedad, encontrando que las lesiones presentan diámetros significativamente menores en los grupos tratados con etileno y altas concentraciones de nitrógeno disponible. Se identificaron genes de etileno, defensa y nitrógeno que responden diferencialmente a la combinación de la etileno, nitrógeno y tiempo de infección. Paralelamente, se realizó una comparación de los transcriptomas de tomate y A. thaliana, identificando diferencias sutiles en el comportamiento transcriptómico de ambas especies asociadas a la biodisponibilidad de nitrógeno. En conjunto, estos resultados indican una diafonía entre etileno y nitrógeno dependiente del tiempo de infección durante el desarrollo de la enfermedad causada por botrytis en plantas de tomate.
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    Honey and nectar from Quillaja saponaria Mol. (Quillajaceae): botanical characterization, isolation, identification, and biological evaluation of secondary metabolites
    (2025) Nuñez Pizarro, Paula Alejandra; Montenegro Rizzardini, Gloria; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    Honey is a natural sweet food produced by bees, revered for its distinct flavor, nutritional value, and health benefits. Beekeeping in Chile offers a diverse range of honey varieties, many of them unique. Quillay (Quillaja saponaria Molina, soapbark tree) is an endemic tree that grows in the sclerophyllous forests and matorral of central Chile standing as one of the country’s most significant melliferous species due to its high appeal to bees as a nectar source. This study focuses on the characterization and biological evaluation of honey and floral nectaries from Quillaja saponaria Mol. (Quillajaceae). The main objective was to identify a reliable chemical quality indicator of monofloral quillay honey by studying its chemical composition and linking it to its biological properties, emphasizing the antioxidant and antibacterial capacities. The evaluation of its hepatoprotective effects in vitro was also accomplish. Chilean honey samples were analyzed, in an attempt to find quillay honey. The botanical origin of honey samples was determined through the melissopalynology method, and a DNA-based method was performed to identify quillay monofloral honey. Honey samples and quillay nectaries were chemically characterized to identify the phenolic acids and flavonoids through HPLC-DAD, including measuring of total phenolic and flavonoid contents in honey samples. Also, chromatographic methods were used to isolated and identify chemical compounds from quillay honey. Finally, an evaluation of the biological properties of samples, including antioxidant capacity through oxygen radical absorbance capacity (ORAC-FL) and ferric reducing antioxidant power (FRAP) assays, antibacterial activity against pathogenic bacteria, and hepatoprotective potential in HuH-7 liver cell models was carried out. The PCR amplification confirmed the qualitative presence of Quillaja saponaria DNA in samples classified as monofloral based on melissopalynology. Monofloral quillay honey exhibited a higher total phenolic content (TPC) and flavonoid content (TFC) than multifloral honey. Additionally, the Spearman correlation indicates a positive and moderate association between the percentage of quillay pollen and the concentration of TPC in honey samples (R = 0.667), suggesting that phenolic content from quillay tree could contribute to the overall antioxidant capacity of this monofloral honey. The exploration and comparison of phenolic compounds in quillay nectaries and honey samples via HPLC-DAD enable us to propose chrysin and syringic acid as quality indicators for quillay monofloral honey. All honey samples demonstrated effectiveness against S. pyogenes, with a not statistically significant positive Spearman correlation (R = 0.07) between the percentage of quillay pollen and the antibacterial activity observed. In vitro assays in HuH-7 cell cultures revealed hepatoprotective effects of quillay honey extracts, linked to their ability to reduce oxidative damage induced by peroxyl radicals.The findings highlight the unique chemical and biological properties of Quillaja saponaria honey, supporting its potential as a high-value product with therapeutic applications. The research underscores the importance of integrating chemical and botanical analyses for honey authentication and characterization. Future studies are recommended to validate these findings using larger sample sizes and diverse experimental models.
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    Mínimo uso de fungicida para el control de Botrytis cinerea en uva de mesa cv. Thompson Seedless
    (2022) González Araya, Javiera; Zoffoli, Juan Pablo; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    Gray mold, caused by Botrytis cinerea, is the main disease in table grape during postharvest. The cultivar Thompson Seedless is especially susceptible and it is exposed to multiple pre-harvest fungicide applications to prevent the infections that occur in flowering and during the berry ripening. Frequently the infection occurs at the flowering phase and remains quiescent until the berries start ripening or even showing an asymptomatic infection until it is expressed during post-harvest. The objectives of the study were to evaluate the effect of reduced application of fungicide, assessed through an infecting predictive model of B. cinerea and two shading conditions on decay and harvest and post-harvest quality of table grapes cv. Thompson Seedless. The fungicide treatment effect was evaluated (reduction of 2 fungicidal applications according to the infection model based in hours of wet foliage and temperature) and the shading effect (shading of 65% and 85%) in a factorial design. The fruit was harvested at two harvest times, and it was evaluated after 60 days in 0° plus 3 days in 20° C. A low gray mold incidence was found, the treatments did not affect the disease development, the model corroborated that the micro-environmental conditions for B. cinerea infection did not achieve a critical value. The use of shadow nets affects the berries quality, the shadowing treatments delay in 7 days the ripening of the berries and increase the incidence of berry splitting during postharvest. The effect of hairline cracks, shatter and bleaching was variable.