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Lavalle, Argentina

Ruiz V.E.,CONICET | Interdonato R.,Catedra de Fisiologia Vegetal | Cerioni L.,CONICET | Albornoz P.,Institute Morfologia Vegetal | And 4 more authors.
Journal of Photochemistry and Photobiology B: Biology | Year: 2016

UV-B radiation (UVBR) is a small fraction of the solar spectrum from 280 to 315 nm. UVBR produces photomorphogenic acclimation responses in plants, modulating their cellular structure and physiology. Here, changes in the peel of harvested lemons after short time exposure to UVBR were analyzed and its potential effects against fungal infection were studied. In the flavedo, UVBR treatment induced variations in the respiratory profiles and increased the phenolic compound contents. Final products of the flavonoid pathway (flavones, flavonols and anthocyanins) increased more markedly than their precursors (flavanones and dihydroflavonols). The increased accumulation of soluble phenolics in the flavedo of treated lemons is associated with the high antioxidant activity found in the flavedo of these samples. Supporting the biochemical determinations, anatomical observations showed abundant intravacuolar deposits of phenolic compounds and an increase in the cell wall thickness in UVBR-treated samples. Metabolic and anatomical modifications associated to UVBR improved natural defenses against Penicillium digitatum, the causal agent of green mold disease. Our results suggest that mature postharvest lemons exposed to the artificial radiation showed phenotypic plasticity, allowing an acclimation response to UVBR which confers fruit resistance to pathogens. Thus, combination of UVBR with other treatments could represent an important improvement to control postharvest diseases on citrus. © 2016 Elsevier B.V. All rights reserved.

Cerioni L.,CONICET | Rodriguez-Montelongo L.,CONICET | Ramallo J.,SA San Miguel | Prado F.E.,Catedra de Fisiologia Vegetal | And 2 more authors.
Postharvest Biology and Technology | Year: 2012

A sequential oxidative treatment (SOT), using sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) in the presence of a cupric salt inhibited in vitro growth and germination of Penicillium digitatum conidia, causal agent of citrus green mold. Here, modifications of this SOT were evaluated in vivo to control this disease in inoculated lemons. The treatment that consisted of two sequential 2-min baths: one with 200mgL-1 NaClO followed by a second with 600mmolL-1 H2O2 in the presence of 6mmolL-1 CuSO4, resulted in 50% of disease control. When this treatment was combined with a third 2-min bath containing 30gL-1 NaHCO3 at 37°C (SOT-NaHCO3) and applied at 24h post-inoculation, green mold incidence was reduced to ∼5%. In non-inoculated lemons stored at 5°C for 45 d, this treatment did not modify the appearance or weight compared to untreated lemons. Furthermore, phenolic content and the oxygen consumption rate in flavedo and albedo tissues were not affected by the SOT-NaHCO3. The malondialdehyde content in flavedo tissues increased immediately after treatment, but decreased to levels similar to control fruit 2 d later. The SOT-NaHCO3 combines compounds that are safe to the environment and human health, thus it represent a potential alternative to synthetic fungicides for the integrated control of postharvest diseases. © 2011 Elsevier B.V..

Sepulveda M.,SA San Miguel | Cuevas I.I.,SA San Miguel | Smilanick J.L.,U.S. Department of Agriculture | Cerioni L.,CONICET | And 2 more authors.
Scientia Horticulturae | Year: 2015

Long distance to markets limits global competitiveness in lemon fruit production due to fungal postharvest decays, such as green mold caused by Penicillium digitatum. Imazalil, the main fungicide used, is formulated as an emulsifiable concentrate (IEC) and as a water-soluble sulphate salt (IS), the later being less commonly applied in most of the producing countries. The aim of the present report was to improve the effectiveness of imazalil treatments to control green mold in commercial scale. In both laboratory and commercial applications, IS was more effective than IEC. IS formulation applied in water followed by IEC applied in wax is an improved option that provided suitable disease control and optimal residue loading >2.0mgL-1 without exceeding the maximum residue levels. Additionally, IMZ residues remained at acceptable levels after 28 days at 7°C, assuring the protection of lemon fruit for long periods of storage and transports. © 2015 Elsevier B.V.

Cerioni L.,CONICET | Sepulveda M.,SA San Miguel | Rubio-Ames Z.,University of California at Riverside | Volentini S.I.,CONICET | And 4 more authors.
Postharvest Biology and Technology | Year: 2013

The effectiveness of potassium sorbate, sodium bicarbonate and potassium phosphite combined with heat and hydrogen peroxide in the presence of CuSO4 to control major lemon postharvest diseases was investigated on artificially infected fruit. Green and blue molds, which both require wounds for infections to occur, were controlled by combination of hydrogen peroxide followed by inorganic salts, even when the temperature solutions were 25°C. Control of sour rot was poor with salt solutions alone but significantly improved in treatments including hydrogen peroxide followed by potassium sorbate or sodium bicarbonate at 50°C. Phomopsis stem-end rot was effectively controlled by potassium sorbate and potassium phosphite at 20°C, and diplodia stem-end rot was partially controlled only by potassium sorbate. Applications of either potassium sorbate or a sequence of hydrogen peroxide followed by potassium phosphite were the most promising treatments, primarily because they controlled most of the diseases without the need to heat the solutions. These treatments controlled postharvest citrus diseases to useful levels and could be suitable alternative to conventional fungicides, or could be applied with them to improve their performance or to manage fungicide resistant isolates. © 2013 Elsevier B.V.

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