Abstract: Mannose-6 phosphate isomerase(PMI)is encoded by the manA/pmi gene from some bacteria as a selectable mker which has been used for the transformation of plant.The novel pmi gene WaS cloned from E.cell DHIOB strain according to homologous sequence by PCR methods.Then,a prokaryotie vector pEPMi and a plant expression vector pCPMi both harboring pmi gene wele constructed respectively.The prokaryotic vector pEPMi with histag was transformed into Escherichia coli to express PMI protein.A single band on SDS-PAGE gel was presented by optimizing the concentration of imidazole in the buffers during the PMI protein isolation.Then,western blot assay confirmed that the induced target protein Wits PMI protein fused His tag,the size of protein is about 46 kDa.The results of analysis of enzyme reaction indicated that PMI has catalyzed the conversion of mannose-6··phosphate to fractose6 phosphate Wihigh efficiency.In addition.plant expression vector pCPMi WaS transformed into tobacco by Agrobacwrium-mediated system,and 72 of 96 independent tobacco transformants were confirmed to contain the pmi gene by PCR detection.So the novel pmi gene can be directly used in plant transformation as a kind of safe selectable marker.

Key words: Mannose-6-phosphate isomerase(PMI), Escherhchis coli, Fructose, Selection marker

CLC Number: 

• Q785