Browsing by Author "Arancibia-Guerra, Camila"

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    A multiomics integrative analysis of color de-synchronization with softening of 'Hass' avocado fruit: A first insight into a complex physiological disorder
    (2023) Nunez-Lillo, Gerardo; Ponce, Excequel; Arancibia-Guerra, Camila; Carpentier, Sebastien; Carrasco-Pancorbo, Alegria; Olmo-Garcia, Lucia; Chirinos, Rosana; Campos, David; Campos-Vargas, Reinaldo; Meneses, Claudio; Pedreschi, Romina
    Exocarp color de-synchronization with softening of 'Hass' avocado is a relevant recurrent problem for the avocado supply chain. This study aimed to unravel the mechanisms driving this de-synchronization integrating omics datasets from avocado exocarp of different storage conditions and color phenotypes. In addition, we propose potential biomarkers to predict color synchronized/de-synchronized fruit. Integration of transcriptomics, proteomics and metabolomics and network analysis revealed eight transcription factors associated with differentially regulated genes between regular air (RA) and controlled atmosphere (CA) and twelve transcription factors related to avocado fruit color de-synchronization control in ready-to-eat stage. CA was positively correlated to auxins, ethylene, cytokinins and brassinosteroids-related genes, while RA was characterized by enrichment of cell wall remodeling and abscisic acid content associated genes. At ready-to-eat higher contents of flavonoids, abscisic acid and brassinosteroids were associated with color-softening synchronized avocados. In contrast, de-synchronized fruit revealed increases of jasmonic acid, salicylic acid and auxin levels.
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    Color desynchronization with softening of 'Hass' avocado: Targeted pigment, hormone and gene expression analysis
    (2022) Arancibia-Guerra, Camila; Nunez-Lillo, Gerardo; Caceres-Mella, Alejandro; Carrera, Esther; Meneses, Claudio; Kuhn, Nathalie; Pedreschi, Romina
    Main determinants of 'Hass' avocado quality and consumer acceptance are mesocarp firmness and skin color. Relevant producing and exporting countries have evidenced during the last seasons color desynchronization with softening at edible ripeness. The mechanisms driving this desynchronization are still unknown. Thus, this study aimed to provide a first deep insight into this problem by combining targeted pigment, hormone and gene expression analysis in avocado exocarp samples from different harvests and storage conditions. Results showed that color desynchronization was more pronounced in regular air (RA) condition and early harvest for all or-chards. Prolonged controlled atmosphere (CA) storage synchronized color development in all orchards analyzed. Chlorophylls and carotenoids did not decrease in content as the fruit reached the ready to eat stage but remained stable while total anthocyanins increased in all evaluated orchards. Total anthocyanins and abscisic acid were strongly and positively correlated with the "black color" phenotype. The other evaluated hormones (JA, IAA, SA, tZ, DHZ, iP) revealed negative correlations with the "black color" phenotype. Gene expression related to the ethylene biosynthesis pathway (PamACS, PamETR avocado gene orthologues) showed an up-regulation in fruit phenotyped as ready to eat (RTE) Green. In addition, the expression of the genes orthologues PamPAL, PamF3H and PamCHS was also positively correlated with anthocyanin content in the skin. Our results revealed that color desynchronization with softening of 'Hass' avocado is quite complex in terms of hormonal interplay and the role of storage conditions (RA vs CA). Thus, further studies need broader approaches such as the incorporation of omics studies to elucidate the physiological and molecular mechanisms driving color desynchronization.
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    Deciphering the behind blackspot exocarp disorder in avocado cv. Hass through a hormonal, transcriptional and metabolic integration approach
    (2024) Nunez-Lillo, Gerardo; Hernandez, Ignacia; Olmedo, Patricio; Ponce, Excequel; Arancibia-Guerra, Camila; Sepulveda, Laura; Carrasco-Pancorbo, Alegria; Beiro-Valenzuela, Maria Gemma; Carrera, Esther; Banos, Jorge; Campos, David; Meneses, Claudio; Pedreschi, Romina
    Avocado cv. Hass is an important sub-tropical crop with an increasing global demand. However, the avocado supply chain experiences significant fruit losses, particularly during the postharvest stage due to diseases and disorders that manifest after prolonged cold storage or the ready-to-eat stage. The blackspot exocarp disorder, which appears as brown or black blotches only after extended cold storage conditions, leads to substantial commercial losses for exported avocados. This research aimed to identify transcriptomic, metabolomic, and hormonal changes in avocado fruits affected by blackspot disorder, differentiating between the green and black exocarp tissues directly impacted by this physiological disorder. The results showed a correlation between the black-colored exocarp of blackspot affected fruits with high levels of gibberellins, cytokinins, jasmonic acid and salicylic acid hormones. Metabolically, these changes were accompanied by a high fatty acid content of oleate, palmitate and linoleate. Using a metabolic pathway reconstruction analysis, we integrated hormonal and metabolic data with transcriptomic information. This approach identified several genes involved in central carbon metabolism, long-chain fatty acid elongation, and jasmonate/salicylate biosynthesis pathways, as well as a possible accumulation of lignins due to a high expression of genes associated with the phenylpropanoid pathway in the black exocarp of blackspot-affected fruits. These findings suggest that blackspot disorder results from a combination of plant defense mechanisms triggered to strengthen the fruit exocarp tissue.