Estudio comparativo de la respuesta a estrés abiótico entre álamos transgénicos sobreexpresores de un intercambiador vacuolar Na+/H+ (EgNHX1) y una pirofosfatasa vacuolar (EgVP1)
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2018
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es
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Universidad Andrés Bello
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Resumen
Eucalyptus globulus es una de las especies vegetales de mayor demanda en la industria forestal a nivel mundial y en nuestro país. Las características de su pulpa al ser blanca, blanda e impermeable, hacen de este árbol un importante recurso para la generación de papel blanco. En la actualidad, los suelos disponibles aptos para la explotación comercial son escasos, lo cual obliga a la industria a buscar nuevas alternativas, como son los suelos ubicados en centro norte de Chile, sin embargo, éstos se caracterizan por poseer alta salinidad y baja disponibilidad de agua, lo que provoca una disminución de la productividad de las especies forestales. Las altas concentraciones de salinidad y sequía conllevan un incremento del Na+ intracelular, siendo este ion tóxico para la célula en altas concentraciones citosólicas desencadenando una respuesta a estrés en la planta. Una de las estrategias para enfrentar este estrés es la compartamentalización del Na+ en la vacuola. Este proceso es realizado por la proteína antiporter NHX1, la cual necesita un gradiente electroquímico de H+ el que es generado por las bombas transportadoras H+-ATPasa vacuolar (V-ATPasa) y H+-PPasa vacuolar (VP1). En nuestro laboratorio se han aislado y caracterizado los genes codificantes para las proteínas de E.globulus EgNHX1 y EgVP1, además de producir líneas de álamos transgénicas sobreexpresoras para estos genes. Durante este trabajo se realizaron análisis fenotípicos y fisiológicos en plantas de álamos transgénicos EgNHX1 y EgVP1 con el objetivo de determinar si estas dos proteínas otorgan mayor tolerancia al estrés hídrico y salino en comparación con las plantas silvestres. Nuestros resultados sugieren fuertemente que ambas líneas sobreexpresora del gen EgNHX1 como de EgVP1 poseen mejor tolerancia a estos estrés abiótico en comparación con plantas silvestres, manteniendo su fenotipo igual que las plantas del grupo control. Además, nuestros resultados fisiológicos indicaron que las plantas que sobreexpresan estas proteínas de E. globulus no presentan mayores daños oxidativos, manteniéndose las concentraciones de malondialdehído, fuga electrolítica y eficiencia fotosintética en comparación con plantas silvestres. Se determinó que tanto plantas sobreexpresoras de EgNHX1 como EgVP1 poseen similar tolerancia a estos tipos de estrés abióticos y aumentan su tolerancia frente a estos desafíos en comparación con los álamos silvestres.
Eucalyptus globulus is one of the trees with the highest demand in forestry industry worldwide and in our country. Due to some at pulp characteristics such as it is whiteness, softness and impermeability, make this an important resource for the generation of white paper. At present, available lands that are suitable for commercial exploitation of this species are few, forcing the industry to search for new alternatives, such as land located in the northern part of Chile. However, these are characterized by the high salinity and water scarcity, which causes a decrease in the productivity of forest species. The high concentration of salt and drought cause an increase of intracellular Na+, making this ion toxic, a response to stress in the plant. One of the strategies to cope this stress is the compartmentalization of Na+ in the vacuole. This process is carried out by the antiporter protein NHX1, which needs an electrochemical gradient of H+ that is generated by the H+ transport pump-vacuolar ATPase (V-ATPase) and vacuolar H+-PPase (VP1). In our laboratory, we have isolated and characterized the genes coding for the E.globulus proteins EgNHX1 and EgVP1, as well as produced overexpression using these genes. During this work, phenotypic and physiological analyzes were performed on transgenic poplars EgNHX1 and EgVP1 with the objective of establishing if these two proteins confers the greatest tolerance to hydric and saline stress in comparison with wild plants. Our results strongly suggest that both overexpression lines, EgNHX1 and EgVP1, show better tolerance to water and salt stress compared to wild plants, maintaining their phenotype equal to the plants of the control group. In addition, our physiological results indicated that the plants that overexpress these proteins of E. globulus do not present major oxidative damages, maintain the levels of malondialdehyde, electrolytic leakage and photosynthetic efficiency in comparison with wild plants. It was determined that both overexpression lines EgNHX1 and EgVP1 exhibit similar tolerance to these types of abiotic stress compared to wild poplars.
Eucalyptus globulus is one of the trees with the highest demand in forestry industry worldwide and in our country. Due to some at pulp characteristics such as it is whiteness, softness and impermeability, make this an important resource for the generation of white paper. At present, available lands that are suitable for commercial exploitation of this species are few, forcing the industry to search for new alternatives, such as land located in the northern part of Chile. However, these are characterized by the high salinity and water scarcity, which causes a decrease in the productivity of forest species. The high concentration of salt and drought cause an increase of intracellular Na+, making this ion toxic, a response to stress in the plant. One of the strategies to cope this stress is the compartmentalization of Na+ in the vacuole. This process is carried out by the antiporter protein NHX1, which needs an electrochemical gradient of H+ that is generated by the H+ transport pump-vacuolar ATPase (V-ATPase) and vacuolar H+-PPase (VP1). In our laboratory, we have isolated and characterized the genes coding for the E.globulus proteins EgNHX1 and EgVP1, as well as produced overexpression using these genes. During this work, phenotypic and physiological analyzes were performed on transgenic poplars EgNHX1 and EgVP1 with the objective of establishing if these two proteins confers the greatest tolerance to hydric and saline stress in comparison with wild plants. Our results strongly suggest that both overexpression lines, EgNHX1 and EgVP1, show better tolerance to water and salt stress compared to wild plants, maintaining their phenotype equal to the plants of the control group. In addition, our physiological results indicated that the plants that overexpress these proteins of E. globulus do not present major oxidative damages, maintain the levels of malondialdehyde, electrolytic leakage and photosynthetic efficiency in comparison with wild plants. It was determined that both overexpression lines EgNHX1 and EgVP1 exhibit similar tolerance to these types of abiotic stress compared to wild poplars.
Notas
Tesis (Magíster en Biotecnología)
Esta tesis se realizó en el centro de Biotecnología Vegetal de la Facultad de Ciencias Biológicas de la Universidad Andrés Bello y fue financiada por Fundación Ciencia & Vida a través del Proyecto PFB-016
Esta tesis se realizó en el centro de Biotecnología Vegetal de la Facultad de Ciencias Biológicas de la Universidad Andrés Bello y fue financiada por Fundación Ciencia & Vida a través del Proyecto PFB-016
Palabras clave
Eucaliptus Globulus, Suelos, Relación Planta-Suelo, Estrés Abiótico