Browsing by Author "Espinoza, Carmen"

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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.
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    PvMYB60 gene, a candidate for drought tolerance improvement in common bean in a climate change context
    (2024) Martínez Barradas, Vera Isabel; Galbiati, Massimo; Barco Rubio, Francisco Antonio; Paolo, Dario; Espinoza, Carmen; Cominelli, Eleonora; Arce Johnson, Patricio
    Background: Common bean (Phaseolus vulgaris) is one of the main nutritional resources in the world, and a low environmental impact source of protein. However, the majority of its cultivation areas are affected by drought and this scenario is only expected to worsen with climate change. Stomatal closure is one of the most important plant responses to drought and the MYB60 transcription factor is among the key elements regulating stomatal aperture. If targeting and mutating the MYB60 gene of common bean would be a valuable strategy to establish more drought-tolerant beans was therefore investigated. Results: The MYB60 gene of common bean, with orthology to the Arabidopsis AtMYB60 gene, was found to have conserved regions with MYB60 typical motifs and architecture. Stomata-specific expression of PvMYB60 was further confirmed by q-RT PCR on organs containing stomata, and stomata-enriched leaf fractions. Further, function of PvMYB60 in promoting stomata aperture was confirmed by complementing the defective phenotype of a previously described Arabidopsis myb60-1 mutant. Conclusions: Our study finally points PvMYB60 as a potential target for obtaining more drought-tolerant common beans in the present context of climate change which would further greatly contribute to food security particularly in drought-prone countries.