中文摘要：

在十字花科黑腐病菌（Xcc）中,hrp基因对寄主的致病性和非寄主的超敏反应中起核心作用,而hrpG对整个hrp基因簇起调控作用。HrpG为OmpR家族的双组分系统感受调控蛋白,含有两个结构域,分别是N端Response_reg和C端Trans reg_C。本研究利用表达载体pQE-30Xa,成功构建了HrpG的表达重组子,在E.coliM15[pREP4]中进行诱导表达。通过调节诱导温度、IPTG浓度和诱导时间最终确定在温度为20℃,IPTG浓度为0.8mmol/L,诱导表达4h。hrpG基因在宿主细胞E.coli M15获得高效可溶性表达。目前尚未有可溶性HrpG蛋白获得成功表达的报导,本研究中获得HrpG蛋白在大肠杆菌获得大量可溶性的表达,将为in vitro研究HrpG的生理活性,特异的结合位点和调控功能研究打下良好基础。

英文摘要：

hrp cluster is regulated by hrpG,which plays an important core role in invasion and non-host hypersensitive response to pathogesis host.HrpG is one member of the OmpR family response regulator with two conserved domains,which are the_reg at N terminal and the Trans reg_C at C terminal,respectively.Architecture characteristic analysis shows that these two domains are quite different from each other.In this study,we succeed to construct the recombinant plasmid to express the gene of hrpG in E.coli M15[pREP4],when the sequence of hrpG gene was inserted into the expression vector of pQE-30Xa.Up to now,there is no report about the expression of soluble HrpG protein.In order to get the soluble HrpG protein with a higher yield,the reaction of expression of the hrpG protein was optimized by adjusting the tempreture and the concentration of IPTG and the time for induction respectively.The result show the best optimum condition for of the soluble HrpG production in supernatant of cell disrution is induced at 20℃ for 4 h with IPTG concentration 0.8 mmol/L.In summation,we have gotten the soluble expression production of hrpG gene in of E.coli M15 cells,which would provide a groundwork for the studies of the physiological activity and the specific binding site and the function regulation of HrpG protein.