中文摘要：

目的：构建伤寒沙门菌Ty2菌株菌毛亚单位bcfD基因敲除突变株。方法：利用交错PCR得到bcfD基因缺失且含其两侧翼序列的片段，将该片段与pMD18 - T连接，亚克隆到pYG4，电转入大肠埃希菌S17-l／入pir菌株，阳性菌株与受体菌伤寒沙门氏菌Ty2进行固相杂交后筛选。结果：成功获得敲除6￡巾基因序列954bp的敲除突变株。结论：交错PCR有利于细菌基因精确敲除突变株的构建，6徊基因敲除株的构建将为进一步研究该基因在伤寒沙门菌中的功能奠定了基础。

英文摘要：

Objective：To construct fimbriae operon bcfl） gene deletion strain in Salmonella enrerica serova Typhi Ty2. Method：Crossover PCR was used to generate the bcfD deletion construct. A fragment contained the flank sequences of bcfD was obtained and ligated into the pMD 18 -T Easy Vector, and the fragment was then subcloned from this recombinant plasmid into pYG4. The recombinant plasmid pYG4 was then electransformed into Escherichi a coli S17 - 1/~.pir and introduced into S. typhi Ty2 by conjugating. Result：The 954bp of bcfD gene knocked out deficient mutant Ty2 was obtained. Conclusion：It was a foundation to study the detail functions of bcfD in S. enterica serovar Typhi.