Browsing by Author "Defilippi, Bruno G."

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    Cold storage effects on oxidative stress of cv. Red Globe table grape rachises
    (2012) Campos-Vargas, Reinaldo; Zamora, Pablo; Contreras, Rodrigo; Koehler, Hans; Zuniga, Gustavo E.; Perez-Donoso, Alonso; Defilippi, Bruno G.
    R. Campos-Vargas, P. Zamora, R. Contreras, H. Kohler, G.E. Zuniga, A. Perez-Donoso, and B.G. Defilippi. 2012. Cold storage effects on oxidative stress of Red Globe table grape rachises. Cien. Inv. Agr. 39(1): 91-104. Table grape (Vitis vinifera L.) quality includes the condition of both the berries and the rachis. In the present report, physiological parameters of Red Globe rachises from fully elongated inflorescences (RFEI) and from mature clusters were studied after storage at 0 or 20 C for different durations. To understand changes in rachis physiology as a result of changes in temperature conditions and storage time, the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were measured. In addition, hydrogen peroxide content, membrane lipoperoxidation (TBARS), total phenolic compounds and antioxidant capacity (FRAP) were assayed. TBARS was higher in mature rachises than in RFEI. This parameter remained constant throughout storage, indicating a change presumably associated with ontogeny or senescence processes. Short-term storage (0-96 11) increased SOD. CAT and APX activities in RFEI, while in mature rachises, no changes were observed in enzyme activities or in hydrogen peroxide content. Longer cold storage (25 or 53 days at 0 degrees C) of mature rachises reduced CAT activity, but SOD and APX activities did not change under these conditions. At Oh, the FRAP and total phenolic contents of mature rachises were three and 20 times higher than in immature rachises, respectively.
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    Proteomic and Low-Polar Metabolite Profiling Reveal Unique Dynamics in Fatty Acid Metabolism during Flower and Berry Development of Table Grapes
    (2023) Olmedo, Patricio; Vidal, Juan; Ponce, Excequel; Defilippi, Bruno G.; Perez-Donoso, Alonso G.; Meneses, Claudio; Carpentier, Sebastien; Pedreschi, Romina; Campos-Vargas, Reinaldo
    Grapevine development and ripening are complex processes that involve several biochemical pathways, including fatty acid and lipid metabolism. Fatty acids are essential components of lipids, which play crucial roles in fruit maturation and flavor development. However, the dynamics of fatty acid metabolism in grape flowers and berries are poorly understood. In this study, we present those dynamics and investigate the mechanisms of fatty acid homeostasis on 'Thompson Seedless' berries using metabolomic and proteomic analyses. Low-polar metabolite profiling indicated a higher abundance of fatty acids at the pre-flowering and pre-veraison stages. Proteomic analyses revealed that grape flowers and berries display unique profiles of proteins involved in fatty acid biosynthesis, triacylglycerol assembly, fatty acid beta-oxidation, and lipid signaling. These findings show, for the first time, that fatty acid metabolism also plays an important role in the development of non-oil-rich tissues, opening new perspectives about lipid function and its relation to berry quality.
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    Proteomic and metabolomic integration reveals the effects of pre-flowering cytokinin applications on central carbon metabolism in table grape berries
    (2023) Olmedo, Patricio; Nunez-Lillo, Gerardo; Vidal, Juan; Leiva, Carol; Rojas, Barbara; Sagredo, Karen; Arriagada, Cesar; Defilippi, Bruno G.; Perez-Donoso, Alonso G.; Meneses, Claudio; Carpentier, Sebastien; Pedreschi, Romina; Campos-Vargas, Reinaldo
    Consumers around the world prefer high quality table grapes. To achieve higher quality traits at ripening, grapevine producers apply different plant growth regulators. The synthetic cytokinin forchlorfenuron N- (2-chloro-4-pyridinyl)-N '-phenylurea (CPPU) is widely used, its effect on grape quality is poorly understood. We hypothesized that the use of CPPU in pre-flowering can lead to changes in the metabolism that affects grape quality at harvest. Therefore, we investigated the role of CPPU applications on the quality of grapes by inte-grating proteomics and metabolomics. CPPU-treated grapevines showed a significant increase in berry size and firmness. Proteomic analyses indicated that CPPU-treated berries accumulated enzymes associated with carbo-hydrate metabolism, glycolysis, and tricarboxylic acid (TCA) cycle at harvest. Metabolomic analyses showed shifts in the abundance of compounds associated with carbohydrate metabolism and TCA cycle in CPPU-treated grapes. These findings suggest that CPPU applications modulate central carbon metabolism, improving grape berry quality.
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    Response Mechanisms of "Hass" Avocado to Sequential 1-methylcyclopropene Applications at Different Maturity Stages during Cold Storage
    (2022) Olivares, Daniela; Garcia-Rojas, Miguel; Ulloa, Pablo A.; Riveros, Anibal; Pedreschi, Romina; Campos-Vargas, Reinaldo; Meneses, Claudio; Defilippi, Bruno G.
    1-Methylcyclopropene (1-MCP) is used for extending the postharvest life of the avocado during storage. Evaluated the effect of 1-MCP application at different times after harvest, i.e., 0, 7, 14, and 21 d at 5 degrees C, to identify the threshold of the ethylene inhibition response in "Hass" avocado. Our results showed that fruits from two maturity stages at harvest: low dry matter (20-23%) and high dry matter (27%). Changes in ethylene production rates and transcript accumulation of genes involved in ethylene metabolism were measured at harvest and during storage. 1-MCP treated fruit up to 14 d of storage showed similar values of firmness and skin color as fruit treated at harvest time. In contrast, when the application was performed after 21 d, the fruit showed ripening attributes similar to those of the untreated ones. To further understand the molecular mechanisms responsible for the lack of response to 1-MCP at 21 d of storage, transcriptomic analysis was performed. Gene ontology analyses based on the DEG analysis showed enrichment of transcripts involved in the 'response to ethylene' for both maturity stages. All genes evaluated showed similar expression profiles induced by cold storage time, with a peak at 21 d of storage and an increased softening of the fruit and peel color. This was a two-year field study, and results were consistent across the two experimental years. Our results should help growers and markets in selecting the optimal timing of 1-MCP application in "Hass" avocados and should contribute to a deeper understanding of the molecular mechanisms of the avocado ripening process.
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    Study of physiological and quality parameters during development and ripening of pepino (Solanum muricatum Aiton) fruit
    (2019) Contreras, Carolina; Schwab, Wilfried; Mayershofer, Mechthild; Morales, Ignacio; Gonzalez-Agueero, Mauricio; Defilippi, Bruno G.
    Pepino (Solanum muricatum Aiton) fruit served as an important crop in Pre-Columbian Andean cultures. Despite the fact that pepino has been known for centuries, information about maturity indices and physiological quality parameters of its fruit is scarce. The objective was to increase our knowledge of pepino fruit physiology and maturity to improve fruit handling and storage. Pepin fruit were studied during 2015 and 2016 seasons. During 2015, developmental and maturity studies were carried out, whereas in 2016 the developmental study was repeated. Twenty-five fruit were analyzed during six developmental stages ranging from immature (stage 1) to senescent fruit (stage 6). Fruit were analyzed for soluble solid content (SSC), titratable acidity (TA), color, respiration and ethylene production, soluble sugars, organic acids, and aroma. For the maturity assay, nonsignificant differences were found between green background color (M1) and white background color (M2) in the different quality parameters, with the exception of firmness. Pepin is a non-climacteric fruit with a low ethylene production rate. Unlike foreign cultivars, Chilean pepinos have low amounts of citric acid, being the predominant acids: malic and quinic. Out of 22 volatile compounds identified in this study, the predominant aroma volatiles are 3-methyl-3-butenyl acetate and 3-methyl-2-butenyl acetate from the terpenoid pathway, and trans-2-hexenal from the lipoxygenase pathway. The quality parameters changing in a ripening-dependent manner were firmness, SSC, aroma and color. Other parameters such as TA and organic acids stayed constant throughout development. In addition to color and SSC, this study also suggests aroma as a harvest index.