Browsing by Author "Carrasco, David"

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    Differences in berry primary and secondary metabolisms identified by transcriptomic and metabolic profiling of two table grape color somatic variants
    (2019) Santibáñez, Claudia; Meyer Regueiro, Carlos José; Martínez, Litsy; Moyano, Tomás; Lunn, John; Feil, Regina; Dai, Zhanwu; Carrasco, David; Arroyo García, Rosa; Hilbert,Ghislaine; Renaud, Christel; Delrot, Serge; Manke Nachtigall, Fabiane; Gutiérrez Ilabaca, Rodrigo Antonio; Matus, José Tomás; Gomès, Eric; Arce Johnson, Jorge Patricio
    Anthocyanins are flavonoids responsible for the color of berries in skin-pigmented grapevine (Vitis vinifera L.). Due to the widely adopted vegetative propagation of this species, somatic mutations occurring in meristematic cell layers can be fixed and passed into the rest of the plant when cloned. In this study we focused on the transcriptomic and metabolic differences between two color somatic variants. Using microscopic, metabolic and mRNA profiling analyses we compared the table grape cultivar (cv.) ‘Red Globe’ (RG, with purplish berry skin) and cv. ‘Chimenti Globe’ (CG, with a contrasting reddish berry skin color). As expected, significant differences were found in the composition of flavonoids and other phenylpropanoids, but also in their upstream precursors’ shikimate and phenylalanine. Among primary metabolites, sugar phosphates related with sucrose biosynthesis were less accumulated in cv. ‘CG’. The red-skinned cv. ‘CG’ only contained di-hydroxylated anthocyanins (i.e. peonidin and cyanidin) while the tri-hydroxylated derivatives malvidin, delphinidin and petunidin were absent, in correlation to the reddish cv. ‘CG’ skin coloration. Transcriptomic analysis showed alteration in flavonoid metabolism and terpenoid pathways and in primary metabolism such as sugar content. Eleven flavonoid 3’5’-hydroxylase gene copies were down-regulated in cv. ‘CG’. This family of cytochrome P450 oxidoreductases are key in the biosynthesis of tri-hydroxylated anthocyanins. Many transcription factors appeared down-regulated in cv. ‘CG’ in correlation to the metabolic and transcriptomic changes observed. The use of molecular markers and its confirmation with our RNA-seq data showed the exclusive presence of the null MYBA2 white allele (i.e. homozygous in both L1 and L2 layers) in the two somatic variants. Therefore, the differences in MYBA1 expression seem sufficient for the skin pigmentation differences and the changes in MYBA target gene expression in cv. ‘Chimenti Globe’.
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    Impact of Shape Factor on Energy Demand, CO2 Emissions and Energy Cost of Residential Buildings in Cold Oceanic Climates: Case Study of South Chile
    (MDPI, 2021) Carpio, Manuel; Carrasco, David
    The increase in energy consumption that occurs in the residential sector implies a higher consumption of natural resources and, therefore, an increase in pollution and a degradation of the ecosystem. An optimal use of materials in the thermal envelope, together with efficient measures in the passive architectural design process, translate into lower energy demands in residential buildings. The objective of this study is to analyse and compare, through simulating different models, the impact of the shape factor on energy demand and CO2 emissions depending on the type of construction solution used in the envelope in a cold oceanic climate in South Chile. Five models with different geometries were considered based on their relationship between exposed surface and volume. Additionally, three construction solutions were chosen so that their thermal transmittance gradually complied with the values required by thermal regulations according to the climatic zone considered. Other parameters were equally established for all simulations so that their comparison was objective. Ninety case studies were obtained. Research has shown that an appropriate design, considering a shape factor suitable below 0.767 for the type of cold oceanic climate, implies a decrease in energy demand, which increased when considering architectural designs in the envelope with high values of thermal resistance.
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    MYB24 orchestrates terpene and flavonol metabolism as light responses to anthocyanin depletion in variegated grape berries
    (2023) Zhang, Chen; Dai, Zhanwu; Ferrier, Thilia; Orduna, Luis; Santiago, Antonio; Peris, Arnau; Wong, Darren C. J.; Kappel, Christian; Savoi, Stefania; Loyola Muñoz, Rodrigo Esteban; Amato, Alessandra; Kozak, Bartosz; Li, Miaomiao; Liang, Akun; Carrasco, David; Meyer Regueiro, Carlos José; Espinoza, Carmen; Hilbert, Ghislaine; Figueroa-Balderas, Rosa; Cantu, Dario; Arroyo-Garcia, Rosa; Arce-Johnson, Patricio; Claudel, Patricia; Errandonea, Daniel; Rodriguez-Concepcion, Manuel; Duchene, Eric; Huang, Shao-Shan Carol; Castellarin, Simone Diego; Tornielli, Giovanni Battista; Barrieu, Francois; Matus, Jose Tomas
    Variegation is a rare type of mosaicism not fully studied in plants, especially fruits. We examined red and white sections of grape (Vitis vinifera cv. 'Bequignol') variegated berries and found that accumulation of products from branches of the phenylpropanoid and isoprenoid pathways showed an opposite tendency. Light-responsive flavonol and monoterpene levels increased in anthocyanin-depleted areas in correlation with increasing MYB24 expression. Cistrome analysis suggested that MYB24 binds to the promoters of 22 terpene synthase (TPS) genes, as well as 32 photosynthesis/light-related genes, including carotenoid pathway members, the flavonol regulator HY5 HOMOLOGUE (HYH), and other radiation response genes. Indeed, TPS35, TPS09, the carotenoid isomerase gene CRTISO2, and HYH were activated in the presence of MYB24 and MYC2. We suggest that MYB24 modulates ultraviolet and high-intensity visible light stress responses that include terpene and flavonol synthesis and potentially affects carotenoids. The MYB24 regulatory network is developmentally triggered after the onset of berry ripening, while the absence of anthocyanin sunscreens accelerates its activation, likely in a dose-dependent manner due to increased radiation exposure. Anthocyanins and flavonols in variegated berry skins act as effective sunscreens but for different wavelength ranges. The expression patterns of stress marker genes in red and white sections of 'Bequignol' berries strongly suggest that MYB24 promotes light stress amelioration but only partly succeeds during late ripening., MYB24 controls metabolic responses in skin sections of variegated grape berries lacking anthocyanin to cope with high-intensity and UV light stress, promoting terpene and flavonol accumulation.