Expression of the coat protein gene of potato leafroll virus in Escherichia coli and development of polyclonal antibodies against recombinant coat protein.

The coat protein (CP) gene of potato leafroll virus (PLRV) was cloned into the pBAD-TOPO expression vector upon induction; the viral protein was expressed as 6XHis-tagged PLRV fusion protein in Escherichia coli (E. coli) BL21 cells. The fusion protein was confirmed by western blot analysis using antibodies specific for the PLRV. The predicted length of the coat protein gene was 627 nucleotides, corresponding to a 209 amino acid coat protein of Mr 23 KDa. The nucleotide sequence of the coat protein gene of PLRV (PLRV-CP) was compared to the sequences of the coat protein genes of other PLRV isolates. The PLRV-CP gene of the Egyptian isolate (PLRV-CP-Eg) was found to be 95% homologous to those of other luteoviruses at the nucleotide level. Antiserum obtained from rabbit after injection with 6XHis-tagged PLRV fusion protein was immuno-reactive towards the PLRV in indirect ELISA.