Estudio de la interacción del factor de transcripción bZIP 17 con el coactivador NPR 1 en respuesta a estrés salino en Arabidopsis thaliana
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2013
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es
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Universidad Andrés Bello
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Licencia CC
Resumen
La respuesta a estrés salino es mediada por la activación de factores de transcripción
del tipo bZIP, como bZIP 17, el que juega un rol en la activación transcripcional de genes
de respuesta a estrés salino. Esta proteína presenta una alta similitud con el factor de
transcripción TGAlb de Tabaco, proteína que interactúa con el coactivador NPR1, para
activación transcripcional de genes de defensa. Esta proteína es regulada por desbalance
redox intracelular, gatillado en condiciones de defensa contra patógenos, todo esto mediado
por la fitohormona ácido salicílico (SA). Utilizando plantas transgénicas que expresan
NPR1 fusionado con GFP, se observó que NPR1 es translocado al núcleo en condiciones de
estrés salino, y, por otro lado, se demostró que ambas proteínas estarían interactuando
mediante la técnica de BiFC. Adicionalmente, los genotipos bzipl7-1, nprl-1 y nprl1/35S:NPR1-GFP presentan fenotipos susceptibles en presencia de estrés salino, de tipo
crónico y agudo. Por otro lado, el (SA) esta involucrado en la respuesta a estrés salino, ya
que la exposición de plantas a NaCl en presencia de bajas concentraciones de SA, presentan
una mejor sobrevivencia. Ensayos de germinación de semillas en presencia de
concentraciones bajas de SA, expuestas a estrés salino, presentan una mayor taza de
sobrevivencia, comparado con las lineas mutantes. Mediante análisis de qRT-PCR se
identificó que en las líneas en estudio los niveles de expresión de genes de respuesta a
estrés salino, que son dependientes de bZIP 17, es menor en comparación al control. Estos
resultados sugieren que ambas proteínas podrían estar siendo claves en la respuesta a estrés
salino en Arabidopsis thaliana, siendo necesaria la presencia de SA intracelular para la
adaptación de la planta frente a estrés salino.
Salt stress response is mediated by the activation of transcription factors bZIP, as bZIP17, which plays a role on transcriptional activation of salt stress response genes. This protein has high similarity with the Tabaco transcription factor TGAlb that interacts with the master regulator NPR1, for transcriptional activation of defense genes. NPR1 is an important component identified downstream SA in the defense to pathogens, which acts as a co-regulator of genes expression. SA leads to NPR1 protein activation by modifications on the intracelular redox balance immediately after pathogen infections, and this seems to be crucial to activate the defense response. Using transgenic plants expressing NPR1 fused to GFP, we observed that NPR1 is translocated to the nucleos upon exposure of NaCl. Moreover, by BiFC technique we found that NPR1 would be interacting with bZIP17. Plants mutants bzipl7-1 and nprl-1, as well as complemented line nprl-1135S:NPR1-GFP showed a susceptible phenotypes in presence of chronic and acute salt stress. Furthermore, SA is involved in salt stress response, since the exposures of plants to NaCl in presence of low concentrations of SA have a better survival. Indeed germination assays in the presence of low concentrations of SA, exposed to salt stress, have an increades survival cup which is not observed in the mutant lines. Analysis by real-time PCR was identified in the lines in study, the expression levels of salt stress marker genes, which are dependent of bZIP17, is minor compared to the control. Taken together our results suggest that both protein could be necessary to promote an effective response under salt stress conditions in Arabidopsis thaliana. and this response required SA for increases the probalitity of plants population adapts to unfavorable condition such as salt stress.
Salt stress response is mediated by the activation of transcription factors bZIP, as bZIP17, which plays a role on transcriptional activation of salt stress response genes. This protein has high similarity with the Tabaco transcription factor TGAlb that interacts with the master regulator NPR1, for transcriptional activation of defense genes. NPR1 is an important component identified downstream SA in the defense to pathogens, which acts as a co-regulator of genes expression. SA leads to NPR1 protein activation by modifications on the intracelular redox balance immediately after pathogen infections, and this seems to be crucial to activate the defense response. Using transgenic plants expressing NPR1 fused to GFP, we observed that NPR1 is translocated to the nucleos upon exposure of NaCl. Moreover, by BiFC technique we found that NPR1 would be interacting with bZIP17. Plants mutants bzipl7-1 and nprl-1, as well as complemented line nprl-1135S:NPR1-GFP showed a susceptible phenotypes in presence of chronic and acute salt stress. Furthermore, SA is involved in salt stress response, since the exposures of plants to NaCl in presence of low concentrations of SA have a better survival. Indeed germination assays in the presence of low concentrations of SA, exposed to salt stress, have an increades survival cup which is not observed in the mutant lines. Analysis by real-time PCR was identified in the lines in study, the expression levels of salt stress marker genes, which are dependent of bZIP17, is minor compared to the control. Taken together our results suggest that both protein could be necessary to promote an effective response under salt stress conditions in Arabidopsis thaliana. and this response required SA for increases the probalitity of plants population adapts to unfavorable condition such as salt stress.
Notas
Trabajo de titulación (Bioquímica, Magíster en Bioquímica)
Palabras clave
Genes, Estrés Salino, Factores de Transcripción, Arabidopsis Thaliana