Examinando por Autor "Melzer, Michael"

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    ÍtemAcceso Abierto
    Expression of a plastid-targeted flavodoxin decreases chloroplast reactive oxygen species accumulation and delays senescence in aging tobacco leaves
    (Frontiers Media, 2018-07-17) Mayta, Martín L.; Lodeyro, Anabella F.; Guiamet, Juan J.; Tognetti, Vanesa B.; Melzer, Michael; Hajirezaei, Mohammad-Reza; Carrillo, Néstor
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    ÍtemAcceso Abierto
    Expression of Flavodiiron Proteins Flv2-Flv4 in Chloroplasts of Arabidopsis and Tobacco Plants Provides Multiple Stress Tolerance
    (MDPI, 2021-01-25) Vicino, Paula; Carrillo, Julieta; Gómez, Rodrigo Lionel; Shahinnia, Fahimeh; Tula, Suresh; Melzer, Michael; Rutten, Twan; Carrillo, Néstor; Hajirezaei, Mohammad-Reza; Lodeyro, Anabella F.; https://orcid.org/0000-0002-8789-0899; https://orcid.org/0000-0001-8236-7647; https://orcid.org/0000-0002-5213-4030
    With the notable exception of angiosperms, all phototrophs contain different sets of flavodiiron proteins that help to relieve the excess of excitation energy on the photosynthetic electron transport chain during adverse environmental conditions, presumably by reducing oxygen directly to water. Among them, the Flv2-Flv4 dimer is only found in β-cyanobacteria and induced by high light, supporting a role in stress protection. The possibility of a similar protective function in plants was assayed by expressing Synechocystis Flv2-Flv4 in chloroplasts of tobacco and Arabidopsis. Flv-expressing plants exhibited increased tolerance toward high irradiation, salinity, oxidants, and drought. Stress tolerance was reflected by better growth, preservation of photosynthetic activity, and membrane integrity. Metabolic profiling under drought showed enhanced accumulation of soluble sugars and amino acids in transgenic Arabidopsis and a remarkable shift of sucrose into starch, in line with metabolic responses of drought-tolerant genotypes. Our results indicate that the Flv2-Flv4 complex retains its stress protection activities when expressed in chloroplasts of angiosperm species by acting as an additional electron sink. The flv2-flv4 genes constitute a novel biotechnological tool to generate plants with increased tolerance to agronomically relevant stress conditions that represent a significant productivity constraint.
  • Miniatura
    ÍtemAcceso Abierto
    Photosynthetic characterization of flavodoxin-expressing tobacco plants reveals a high light acclimation-like phenotype
    (Elsevier, 2020-08-01) Gómez, Rodrigo Lionel; Figueroa, Nicolás; Melzer, Michael; Hajirezaei, Mohammad-Reza; Carrillo, Néstor; Lodeyro, Anabella F.
  • Miniatura
    ÍtemAcceso Abierto
    Providing an additional electron sink by the introduction of cyanobacterial Ffavodiirons enhances growth of A. thaliana under various light intensities
    (Frontiers Media, 2020-06-25) Tula, Suresh; Shahinnia, Fahimeh; Melzer, Michael; Rutten, Twan; Gómez, Rodrigo Lionel; Lodeyro, Anabella F.; Wirén, Nicolaus von; Carrillo, Néstor; Hajirezaei, Mohammad-Reza
  • Miniatura
    ÍtemAcceso Abierto
    Targeting of flavodoxin to chloroplasts of mesophyll but not bundle sheath maize cells confers increased drought tolerance
    (Wiley, 2023-10-09) Demarchi, Mariana; Arce, Rocío C.; Campi, Mabel; Pierella Karlusich, Juan J.; Hajirezaei, Mohammad-Reza; Melzer, Michael; Lodeyro, Anabella F.; Chan, Raquel L.; Carrillo, Néstor; https://orcid.org/0009-0009-2702-6183; https://orcid.org/0000-0001-6549-6316; https://orcid.org/0009-0002-2997-9753; https://orcid.org/0000-0003-1739- 4424; https://orcid.org/0000-0002- 9537-0121; https://orcid.org/0000-0002-5213-4030; https://orcid.org/0000-0001-9208-2194; https://orcid.org/0000-0002-3264-0008; https://orcid.org/0000-0002-8612-5503; Dra. Maurino, Verónica
    Abiotic stresses, especially drought, represent the main factor limiting agricultural productivity world-wide. Maize, one of the top crops in terms of food, feed and biofuel production, is a C4 summer monocotyledoneous species grown as a single-cross hybrid displaying high heterosis (conducive to improved grain yield), and high sensitivity to drought stress at different growth stages (Sheoran et al., 2022). Photosynthesis is an early target of most environmental hardships including drought, which inhibits CO2 assimilation associated with stomatal closing. Under such conditions, reducing power generated by the photosynthetic electron transport chain (PETC) cannot be used in the regenerative step of the Calvin cycle, leading to the accumulation of NADPH, over-reduction of the PETC and downregulation of ferredoxin levels (Tognetti et al., 2006). The excess of excitation energy and reducing equivalents are delivered to adventitious acceptors, mostly O2, with the generation of partially reduced and/or activated energy-rich reactive oxygen species (ROS) such as the superoxide anion radical, hydrogen peroxide and singlet oxygen, which act both as toxic compounds and signaling intermediates (Foyer et al., 2017; Dvořák et al., 2021). Oxidative stress is thus an almost universal outcome of environmental adversities. [...]