Abstract: P56 pectate lyase play an important role during the extension of pollen tube.In order to obtain the antibody of P56 for the study of action machnism and distribution of P56 along pollen tube,the recombinant expression of P56 was carried out in Escherichia coli.The cDNA coding mature P56 without signal peptide was amplified from Solanum lycopersicum by Overlap-PCR.The amplified fragment was ligated to pET28a(+)expression vector,then transformed into Escherichia coli BL21-CodenPlus(DE3)-RIL.The expression of P56 was applied at 0.5 mmol/L IPTG,15℃ and 180 r/min for 60 h.The recombinant protein reached about 30% of total cell proteins and existed as inclusion body in pET-28a(+)-LAT56-BL21-CodenPlus(DE3)-RIL cell.Through Ni²⁺-nitrilotriacetate-agrose affinity chromatography,the recombinant P56 was purified to homology based on SDS-PAGE.