Barr Michelle, East Alison K, Leonard Mary, Mauchline Tim H, Poole Philip S
School of Biological Sciences, University of Reading, Reading, UK.
FEMS Microbiol Lett. 2008 May;282(2):219-27. doi: 10.1111/j.1574-6968.2008.01131.x. Epub 2008 Apr 9.
IVET was used to identify genes that are specifically expressed in the rhizosphere of the pea-nodulating bacterium Rhizobium leguminosarum A34. A library of R. leguminosarum A34 cloned in the integration vector pIE1, with inserts upstream of a promoter-less purN:gfp:gusA, was conjugated into purN host RU2249 and recombined into the genome. After removal of colonies that expressed the reporter genes of the vector under laboratory conditions, the library was inoculated into a nonsterile pea rhizosphere. The key result is that 29 rhizosphere-induced loci were identified. Sequence analysis of these clones showed that a wide variety of R. leguminosarum A34 genes are expressed specifically in the rhizosphere including those encoding proteins involved in environmental sensing, control of gene expression, metabolic reactions and membrane transport. These genes are likely to be important for survival and colonization of the pea rhizosphere.
体内表达技术（IVET）被用于鉴定在豌豆根瘤菌豆科根瘤菌A34根际中特异性表达的基因。将克隆于整合载体pIE1的豆科根瘤菌A34文库（其插入片段位于无启动子的purN:gfp:gusA上游）接合到purN宿主RU2249中，并重组到基因组中。在去除在实验室条件下表达载体报告基因的菌落之后，将该文库接种到非无菌的豌豆根际中。关键结果是鉴定出了29个根际诱导位点。对这些克隆的序列分析表明，豆科根瘤菌A34的多种基因在根际中特异性表达，包括那些编码参与环境感知、基因表达调控、代谢反应和膜转运的蛋白质的基因。这些基因可能对豌豆根际的存活和定殖很重要。
