Browsing by Author "O'Brien, Jose A."

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    Low Salt Treatment Results in Plant Growth Enhancement in Tomato Seedlings
    (2022) Rivera, Paola; Moya, Cristian; O'Brien, Jose A.
    Climate change together with excessive fertilization and poor water quality can affect soil quality and salinization. In plants, high salinity causes osmotic stress, ionic toxicity, and oxidative stress. Consequently, salt stress limits plant development, growth, productivity, and yield. Tomatoes are a very common agricultural product, and some cultivars can partially tolerate salinity. However, most studies are focused on salt excess, which does not necessarily extrapolate on how plants develop in soils with low concentrations of salts. Thus, this study characterizes plant growth and the development of different salt concentrations from 25 to 200 mM in Solanum lycopersicum cv. Moneymaker. Tomato seedlings grown in Murashige and Skoog medium supplied with different NaCl concentrations (0, 25, 50, 75, 100, 125, 150, 175, and 200 mM) showed that low salt concentrations (25 and 50 mM) have a positive impact on lateral root development. This was further observed in physiological parameters such as shoot length, primary root length, and proliferation of lateral roots versus controls. Interestingly, no significant changes in Na+ concentration were observed in 25 mM NaCl in roots or shoots versus controls. Overall, our results suggest that non-toxic salt concentrations can have a positive impact on plant development.
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    Stable Transformation of Arabidopsis thaliana Cell Suspension Cultures: A Case Study for The Overexpression of the COI1 Receptor
    (2021) Diaz-Sanchez, Eva K.; O'Brien, Jose A.; Perez-Salamo, Imma; Krasauskas, Jovaras; Bomer, Moritz; Devoto, Alessandra
    Cell suspension cultures have been studied for decades to produce natural molecules. However, the difficulty in generating stably transformed cell lines has limited their use to produce high value chemicals reproducibly and in elevated quantities.
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    Ultra-Low Oxygen and Preconditioning Storage Regulate Ethylene Synthesis to Prevent Corky Disorders in 'Fuji' Apple
    (2022) Riano, Camila; Ribba, Tomas; Marchant, Juan I.; O'Brien, Jose A.; Contreras, Carolina; Zoffoli, Juan P.
    Corky disorders in apples represent a significant problem for long-term storage where controlled atmosphere (CA) is mainly used. Ultra-low oxygen (ULO) is an alternative to CA, which consists of low partial pressure of O-2 to maintain a low metabolism in the apple fruit, achieving an effective decrease in the ethylene production and physiological disorders. The aim of this research was to study the effectiveness of a short hypoxia period on the development of cork physiological disorders during the storage of apple. 'Fuji' apples were prestored under ULO (0.5 kPa O-2) for two periods of time (15 and 30 days) and at two temperatures (0 or 5 degrees C). Corky physiological disorders increased at 5 degrees C prestorage temperature; however, ULO treatments for 15 or 30 days at 0 or 5 degrees C achieved a significant reduction in corky disorders near to 1%, compared with control treatments. In addition, a considerable reduction in ethylene production for up to 30 days was observed in ULO-treated fruit at 0 and 5 degrees C. ULO for 30 days at 0 and 5 degrees C increased the internal production of ethanol and acetaldehyde, causing a lower sensory quality due to the presence of fermentative flavors in fruit stored at 5 degrees C. ULO of 15 days of conditioning decreased the relative expression of ethylene biosynthesis genes MdACS1 and MdACO1, resulting in lower ethylene production.