Directed Evolution of Dunaliella salina Ds-26-16 and Salt-Tolerant Response in Escherichia coli
AbstractIdentification and evolution of salt tolerant genes are crucial steps in developing salt tolerant crops or microorganisms using biotechnology. Ds-26-16, a salt tolerant gene that was isolated from Dunaliella salina, encodes a transcription factor that can confer salt tolerance to a number of organisms including Escherichia coli (E. coli), Haematococcus pluvialis and tobacco. To further improve its salt tolerance, a random mutagenesis library was constructed using deoxyinosine triphosphate-mediated error-prone PCR technology, and then screened using an E. coli expression system that is based on its broad-spectrum salt tolerance. Seven variants with enhanced salt tolerance were obtained. Variant EP-5 that contained mutation S32P showed the most improvement with the E. coli transformant enduring salt concentrations up to 1.54 M, in comparison with 1.03 M for the wild type gene. Besides, Ds-26-16 and EP-5 also conferred E. coli transformant tolerance to freezing, cold, heat, Cu2+ and alkaline. Homology modeling revealed that mutation S32P in EP-5 caused the conformational change of N- and C-terminal α-helixes. Expression of Ds-26-16 and EP-5 maintained normal cellular morphology, increased the intracellular antioxidant enzymatic activity, reduced malondialdehyde content, and stimulated Nitric Oxide synthesis, thus enhancing salt tolerance to E. coli transformants. View Full-Text
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Guo, Y.; Dong, Y.; Hong, X.; Pang, X.; Chen, D.; Chen, X. Directed Evolution of Dunaliella salina Ds-26-16 and Salt-Tolerant Response in Escherichia coli. Int. J. Mol. Sci. 2016, 17, 1813.
Guo Y, Dong Y, Hong X, Pang X, Chen D, Chen X. Directed Evolution of Dunaliella salina Ds-26-16 and Salt-Tolerant Response in Escherichia coli. International Journal of Molecular Sciences. 2016; 17(11):1813.Chicago/Turabian Style
Guo, Yuan; Dong, Yanping; Hong, Xiao; Pang, Xiaonan; Chen, Defu; Chen, Xiwen. 2016. "Directed Evolution of Dunaliella salina Ds-26-16 and Salt-Tolerant Response in Escherichia coli." Int. J. Mol. Sci. 17, no. 11: 1813.
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