Abstract

Peroxidase is one of the key enzymes of the cellular antioxidant defense system, which is mostly involved in the reduction of hydrogen peroxide. Here, a peroxidase gene, named ThPOD1 was isolated from a cDNA library, which was generated from root tissue of Tamarix hispida that was exposed to 0.4 M NaCl. The cDNA was subcloned in bacterial expression vector pET28a and expressed as N-terminal histidine tagged fusion protein in Escherichia coli (Rosetta gami). After induction with IPTG, a molecular weight of 42 kDa fusion protein was obtained and purified by Ni-NTA affinity chromatography. New Zealand white rabbit was immunized with the purified ThPOD1 protein and the antiserum was obtained. Western blot analyses showed that, the antibody reacted specifically to recombinant ThPOD1 protein. Therefore, the antibody was applied to detect expression of ThPOD1 protein in T. hispida, which was treated with 20% PEG and 100 μM ABA, respectively. All treatments induced an increase in protein level of the ThPOD1 gene, especially the expression levels of ThPOD1 in roots were obviously higher than in leaves. This work established a good foundation for further study on the specific function of ThPOD1 under the condition of abiotic stress.

Key words: Peroxidase, prokaryotic expression, abiotic stress, Tamarix hispida.

Abbreviation

PCR, Polymerase chain reaction; ABA, abscisic acid; IPTG,isopropyl-β-D-thiogalactopyranoside; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; ROS, reactive oxygen species.