Evaluación del rol del gen AtbZIP17 durante la respuesta a estrés osmótico en Arabidopsis thaliana
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Date
2015
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es
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Universidad Andrés Bello
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Abstract
Sequía, salinización de suelos y bajas temperaturas son factores ambientales que limitan el crecimiento y la producción agrícola a nivel mundial, siendo el estrés osmótico un componente común entre estas condiciones. Las vías de señalización gatilladas por estas condiciones han sido estudiadas profundamente durante las pasadas décadas, y se ha identificado a la hormona ácido abscísico (ABA) como el principal componente capaz de modificar la expresión génica, a través de la activación de diversos factores de transcripción. Dentro de estos factores encontramos la familia de factores de transcripción del tipo bZIP, la cual ha sido asociada con la respuesta a diferentes condiciones de estrés. Diversos trabajos indican que el factor de transcripción bZIP17, además de estar involucrado en la respuesta a proteínas mal plegadas participa durante la respuesta a estrés salino y a ABA regulando la expresión de diferentes grupos de genes. Sin embargo, su papel como componente de la respuesta a estrés osmótico es desconocido. En este trabajo se evaluó el papel de bZIP17 en plántulas y semillas bajo una condición que induce estrés osmótico. Para identificar posibles genes regulados por bZIP17, se analizó el transcriptoma de líneas mutante bzip17 en comparación con líneas silvestres de Arabidopsis thaliana, sometidas a tratamientos con manitol mediante secuenciación masiva de fragmentos de cDNA. Dentro de los genes candidatos a ser regulados por bZIP17 se identificaron tres procesos biológicos representados significativamente. El primer proceso biológico está relacionado con la vía de señalización mediada por ABA, el segundo está asociado al desarrollo radicular, y el tercero al desarrollo y dormancia de la semilla. Por otro lado, semillas bzip17 muestran un fenotipo de adelanto en la geminación durante tratamientos con manitol, en comparación a líneas silvestres. Por lo tanto, si bien bZIP17 participa regulando la expresión de genes durante la respuesta a estrés osmótico, éste desarrolla un papel importante durante la germinación de la semilla bajo dicha condición, a través de la regulación de genes involucrados en el desarrollo y dormancia de la semilla de Arabidopsis thaliana.
Drought, salinity and low temperature are environmental conditions that limit the growth and worldwide agricultural production, and the osmotic stress is a common component between these conditions. Over the past decades the signaling pathways triggered by these conditions have been intensively studied, and abcisic acid (ABA) hormone has identified as the main component capable of modifying gene expression trough the activation of various transcription factors. Among these, the family of basic-region leucine zipper (bZIP) transcription factors has been associated with response to various stress conditions. Several studies indicate that the transcription factor bZIP17 are involved in the unfolded protein response, salt stress and ABA response though the regulation of different sets of gene expression. However, its role as a component of the osmotic stress response remains unknown. In this work bZIP17 role during a condition that induces osmotic stress in seedling and seed was evaluated. To identify target gene of bZIP17, the transcriptome of Arabidopsis thaliana bzip17 mutant line and wild type lines under treatment with mannitol was compared. Three biological processes were significantly represented among the candidates genes regulated by bZIP17. The first biological process was associated with the signaling pathway mediated by ABA; the second process was associated with root development; and the third process was involved in the seed development and dormancy. On the other hand, bzip17 mutant line exhibit an accelerated germination process phenotype under treatment with mannitol, compared with wild type plant. Therefore, although bZIP17 participates in the regulation of the gene expression in osmotic stress response, this transcription factor plays an important role during Arabidopsis thaliana seed development and dormancy under osmotic stress response.
Drought, salinity and low temperature are environmental conditions that limit the growth and worldwide agricultural production, and the osmotic stress is a common component between these conditions. Over the past decades the signaling pathways triggered by these conditions have been intensively studied, and abcisic acid (ABA) hormone has identified as the main component capable of modifying gene expression trough the activation of various transcription factors. Among these, the family of basic-region leucine zipper (bZIP) transcription factors has been associated with response to various stress conditions. Several studies indicate that the transcription factor bZIP17 are involved in the unfolded protein response, salt stress and ABA response though the regulation of different sets of gene expression. However, its role as a component of the osmotic stress response remains unknown. In this work bZIP17 role during a condition that induces osmotic stress in seedling and seed was evaluated. To identify target gene of bZIP17, the transcriptome of Arabidopsis thaliana bzip17 mutant line and wild type lines under treatment with mannitol was compared. Three biological processes were significantly represented among the candidates genes regulated by bZIP17. The first biological process was associated with the signaling pathway mediated by ABA; the second process was associated with root development; and the third process was involved in the seed development and dormancy. On the other hand, bzip17 mutant line exhibit an accelerated germination process phenotype under treatment with mannitol, compared with wild type plant. Therefore, although bZIP17 participates in the regulation of the gene expression in osmotic stress response, this transcription factor plays an important role during Arabidopsis thaliana seed development and dormancy under osmotic stress response.
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Tesis (Magíster en Biotecnología)
Tesis financiada por el proyecto FONDECYT No1110954; y el proyecto CONICYT- PAI “Concurso Nacional Apoyo al Retorno de Investigadores/as desde el extranjero, convocatoria 2013 nº 821320026.
Tesis financiada por el proyecto FONDECYT No1110954; y el proyecto CONICYT- PAI “Concurso Nacional Apoyo al Retorno de Investigadores/as desde el extranjero, convocatoria 2013 nº 821320026.
Keywords
Arabidopsis Thaliana, Estrés Osmótico, Genes