[Recombination and fusion expression of porcine defensin gene PBD-I in E. coli]. 
The porcine defensin gene PBD-I was amplified by RT-PCR, then the gene was inserted into expression vector PinPoint(TM) Xa-3.  Recombinant plasmid named as ppd-1 was transformed into E.Coli JM109, which could effectively produce fusion protein induced with IPTG.  The positive clone of PBD-I gene expressed 17kDa fusion protein by SDS-PAGE electrophoresis.  Expression of PBD-I gene didn't increase distinctly along with time.  The expression of PBD-I gene lays a foundation in research on antimicrobial activities and its mechanism of the defensin.