Examinando por Autor "Tula, Suresh"

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    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.
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    ÍtemAcceso Abierto
    Plastid-targeted Cyanobacterial Flavodiiron proteins maintain carbohydrate turnover and enhance drought stress tolerance in barley
    (Frontiers Media, 2021-02-13) Shahinnia, Fahimeh; Tula, Suresh; Hensel, Goetz; Reiahisamani, Narges; Nasr, Nasrin; Kumlehn, Jochen; Gómez, Rodrigo Lionel; Lodeyro, Anabella F.; Carrillo, Néstor; Hajirezaei, Mohammad-Reza
    Chloroplasts, the sites of photosynthesis in higher plants, have evolved several means to tolerate short episodes of drought stress through biosynthesis of diverse metabolites essential for plant function, but these become ineffective when the duration of the stress is prolonged. Cyanobacteria are the closest bacterial homologs of plastids with two photosystems to perform photosynthesis and to evolve oxygen as a byproduct. The presence of Flv genes encoding flavodiiron proteins has been shown to enhance stress tolerance in cyanobacteria. In an attempt to support the growth of plants exposed to drought, the Synechocystis genes Flv1 and Flv3 were expressed in barley with their products being targeted to the chloroplasts. The heterologous expression of both Flv1 and Flv3 accelerated days to heading, increased biomass, promoted the number of spikes and grains per plant, and improved the total grain weight per plant of transgenic lines exposed to drought. Improved growth correlated with enhanced availability of soluble sugars, a higher turnover of amino acids and the accumulation of lower levels of proline in the leaf. Flv1 and Flv3 maintained the energy status of the leaves in the stressed plants by converting sucrose to glucose and fructose, immediate precursors for energy production to support plant growth under drought. The results suggest that sugars and amino acids play a fundamental role in the maintenance of the energy status and metabolic activity to ensure growth and survival under stress conditions, that is, water limitation in this particular case. Engineering chloroplasts by Flv genes into the plant genome, therefore, has the potential to improve plant productivity wherever drought stress represents a significant production constraint.
  • 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