RESUMEN
A 1312 bp 5' flanking region of Salicornia europaea choline monooxygenase (SeCMO) gene was isolated using the anchored PCR. To investigate the mechanism of regulation for this stress-induced gene, the SeCMO promoter--glucuronidase (GUS) chimeric gene constructs containing five deletions F1, F2, F3, F4 and F5 were introduced into tobacco (Nicotiana tabacum L.) by Agrobacterium-mediated transformation. The functional properties of each promoter fragment were examined by assaying GUS activity in the leaves of transgenic tobacco treated with abiotic stresses (NaCl, PEG6000 and low temperature). The GUS activity in transgenic tobacco with F2 (-1056 to +8) construct showed highest increase under all the three abiotic stresses. Thus, the study provided a potential promoter induced by the salt, dehydration and cold for the plant genetic manipulation.
Asunto(s)
Secuencia de Bases , Chenopodiaceae/genética , Chenopodiaceae/metabolismo , Frío , Glucuronidasa/biosíntesis , Glucuronidasa/genética , Datos de Secuencia Molecular , Oxigenasas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/enzimología , Plantas Modificadas Genéticamente/genética , Polietilenglicoles , Regiones Promotoras Genéticas/genética , Cloruro de Sodio , Nicotiana/enzimología , Nicotiana/genéticaRESUMEN
Glycinebetaine (GB) is an osmoprotectant accumulated by certain plants in response to high salinity, drought, and cold stress. Plants synthesize GB via the pathway choline → betaine aldehyde → glycinebetaine, and the first step is catalyzed by choline monooxygenase (CMO). In the present study, by using RT-PCR and RLM-RACE, a full-length CMO cDNA (1844 bp) was cloned from a halophyte Salicornia europaea, which showed high homology to other known sequences. In order to identify its function, the ORF of CMO cDNA was inserted into binary vector PBI121 to construct the chimeric plant expression vector PBI121-CMO. Using Agrobacterium (LBA4404) mediation, the recombinant plasmid was transferred into tobacco (Nicotiana tabacum). The PCR, Southern blot and RT-PCR analysis indicated the CMO gene was integrated into the tobacco genome, as well as expressed on the level of transcription. The transgenic tobacco plants were able to survive on MS medium containing 300 mmol/L NaCl and more vigorous than those of wild type with the same concentration salt treatment. In salt-stress conditions, transgenic plants had distinctly higher chlorophyll content and betaine accumulation than that of the control, while relative electrical conductivity of transgenic plants was generally lower. The results suggested the CMO gene transformation could effectively contribute to improving tobacco salt-resistance.
Asunto(s)
Chenopodiaceae/fisiología , Mejoramiento Genético/métodos , Oxigenasas/fisiología , Plantas Modificadas Genéticamente/fisiología , Proteínas Recombinantes/metabolismo , Tolerancia a la Sal/fisiología , Plantas Tolerantes a la Sal/fisiología , Nicotiana/fisiologíaRESUMEN
Total RNA was extracted from leaf of Suaeda hetroptera kitag, then the CMO ( choline monooxygenase) cDNA was amplified using the reverse transcriptase polymerase chain reaction ( RT-PCR) method and cloned into pMD-T-simple vector. The positive clones from the Blue/White Screen were sequenced. After confirming its validity, the CMO gene fragment was cloned into pBI121 vector. Double enzyme restriction and PCR analysis indicated that the pBI121/CMO recombinant plasmid was successfully constructed.