Expression in Escherichia coli of the gene encoding ascorbate peroxidase from Brassica napus enhances salt tolerance of bacterial cells

Authors: Liu, Z.; Wan, Q.; Yue, Y.; Yang, H.; Wang, J.; Li, X.; Yang, Y.

Source: Russian Journal of Plant Physiology, Volume 58, Number 3, May 2011 , pp. 478-483(6)

Publisher: MAIK Nauka/Interperiodica

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Abstract:

Ascorbate peroxidase (APX) is an important enzyme to scavenge the reactive oxygen species (ROS), which are often caused by the salt stress. Here, APX cDNA from Brassica napus was amplified by RT-PCR and cloned into the prokaryotic expression vector pGEX-6p-1 to express BnAPX as a glutathione S-transferase (GST) fusion protein. The recombinant expression plasmid was then transformed into Escherichia coli BL21 (DE3) and induced with 0.2 mM IPTG at 28°C. The enzyme activity analysis of the induced protein showed the GST-APX protein had the similar enzyme activity with the other found APXs, which decompose H₂O₂. Moreover, the GST-APX fusion protein was purified by affinity chromatography using the glutathione-Sepharose 4B column. The purified GST-APX protein was then used to immunize rabbits to obtain the anti-BnAPX serum, which was suitable to recognize both the recombinant exogenous BnAPX and the endogenous BnAPX in vivo by western blotting and the immunohistochemical experiment. Furthermore, the immuno-fluorescent microscopy observation revealed that BnAPX was expressed in the chloroplasts. Finally, the bacteria expressing BnAPX grew much faster in the presence of 3% NaCl than the control cells, indicating that the transformant expressing BnAPX acquired resistance to salt stress.

Keywords: Brassica napus; Escherichia coli; ascorbate peroxidase; reactive oxygen; salt stress

Document Type: Research article

DOI: http://dx.doi.org/10.1134/S1021443711030113

Affiliations: 1: Email: yangyi538@163.com

Publication date: 2011-05-01