Examinando por Autor "Defilippi, B.G."

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  • Miniatura
    Ítem
    Cell wall calcium and hemicellulose have a role in the fruit firmness during storage of blueberry (Vaccinium spp.)
    (MDPI AG, 2021-03) Olmedo, P.; Rojas, B.; Silva-Sanzana, C.; Delgado-Rioseco, J.; Fernández, K.; Balic, I.; Arriagada, C.; Moreno, A.A.; Defilippi, B.G.; Campos-Vargas, R.
    The firmness of blueberry is one of its most significant quality attributes. Modifications in the composition of the cell wall have been associated with changes in the fruit firmness. In this work, cell wall components and calcium concentration in two blueberry cultivars with contrasting firmness phenotypes were evaluated at harvest and 30 days cold storage (0◦ C). High performance anion-exchange chromatography with pulse amperometric detector (HPAEC-PAD) analysis was performed using the “Emerald” (firmer) and “Jewel” (softer) blueberry cultivars, showing increased glucose in the firmer cultivar after cold storage. Moreover, the LM15 antibody, which recognizes xyloglucan domains, displayed an increased signal in the Emerald cultivar after 30 d cold storage. Additionally, the antibody 2F4, recognizing a homogalacturonan calcium-binding domain, showed a greater signal in the firmer Emerald blueberries, which correlates with a higher calcium concentration in the cell wall. These findings suggest that xyloglucan metabolism and a higher concentration of cell wall calcium influenced the firmness of the blueberry fruit. These results open new perspectives regarding the role of cell wall components as xyloglucans and calcium in blueberry firmness. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
  • Miniatura
    Ítem
    The unusual acid-accumulating behavior during ripening of cherimoya (Annona cherimola Mill.) is linked to changes in transcription and enzyme activity related to citric and malic acid metabolism
    (MDPI AG, 2016) González-Agüero, M.; Pardo, L.T.; Zamudio, M.S.; Contreras, C.; Undurraga, P.; Defilippi, B.G.
    Cherimoya (Annona cherimola Mill.) is a subtropical fruit characterized by a significant increase in organic acid levels during ripening, making it an interesting model for studying the relationship between acidity and fruit flavor. In this work, we focused on understanding the balance between the concentration of organic acids and the gene expression and activity of enzymes involved in the synthesis and degradation of these metabolites during the development and ripening of cherimoya cv. “Concha Lisa”. Our results showed an early accumulation of citric acid and other changes associated with the accumulation of transcripts encoding citrate catabolism enzymes. During ripening, a 2-fold increase in malic acid and a 6-fold increase in citric acid were detected. By comparing the contents of these compounds with gene expression and enzymatic activity levels, we determined that cytoplasmic NAD-dependent malate dehydrogenase (cyNAD-MDH) and mitochondrial citrate synthase (mCS) play important regulatory roles in the malic and citric acid biosynthetic pathways.
  • Miniatura
    Ítem
    Transcriptome analysis during ripening of table grape berry cv. Thompson Seedless
    (Public Library of Science, 2018) Balic, I.; Vizoso, P.; Nilo-Poyanco, R.; Sanhueza, D.; Olmedo, P.; Sepúlveda, P.; Arriagada, C.; Defilippi, B.G.; Meneses, C.; Campos-Vargas, R.
    Ripening is one of the key processes associated with the development of major organoleptic characteristics of the fruit. This process has been extensively characterized in climacteric fruit, in contrast with non-climacteric fruit such as grape, where the process is less understood. With the aim of studying changes in gene expression during ripening of non-climacteric fruit, an Illumina based RNA-Seq transcriptome analysis was performed on four developmental stages, between veraison and harvest, on table grapes berries cv Thompson Seedless. Functional analysis showed a transcriptional increase in genes related with degradation processes of chlorophyll, lipids, macromolecules recycling and nucleosomes organization; accompanied by a decrease in genes related with chloroplasts integrity and amino acid synthesis pathways. It was possible to identify several processes described during leaf senescence, particularly close to harvest. Before this point, the results suggest a high transcriptional activity associated with the regulation of gene expression, cytoskeletal organization and cell wall metabolism, which can be related to growth of berries and firmness loss characteristic to this stage of development. This high metabolic activity could be associated with an increase in the transcription of genes related with glycolysis and respiration, unexpected for a non-climacteric fruit ripening.