Expression of Citrus tristeza virus coat protein gene in Escherichia coli

Citrus tristeza virus (CTV) is among the most destructive pathogens of citrus and causes substantial economic losses in citrus-growing industry worldwide. Considering recent distribution of this pathogen and its capability of transmission by existing aphid vectors in Iran, detection of this virus is enforceable for controlling the damage caused by this pathogen in Iran, as one of the major citrus producing countries. Toward this aim, developing a reliable and sensitive detection method such as enzyme- linked immunosorbant assay (ELISA) would be the first step to detect CTV in large scale screenings of field samples. As the serological method requires great amounts of specific antibody, the consequent preparation of a large scale antigen source for immunization process is necessary. In this study the coat protein gene of CTV (CP25) was amplified by polymerase chain reaction from a cloned CP25 gene in pTZ57R/T and subcloned in pET26b expression vector and named pET-CP25. Two Escherichia coli strains of BL21 and Rosetta Gami (DE3) were transformed by pET-CP25. Expression of recombinant protein was induced by IPTG. The authenticity of recombinant protein was confirmed by western immunoblot analysis using a polyclonal antiserum against CTV particles. The results indicated that CTV coat protein gene was expressed in E.coli. This recombinant protein could be used as a source of antigen for immunization process.