中文摘要：

GntR 类型 transcriptional 管理者在细菌调整最多样的生物过程。尽管 GntR 类型 transcriptional 管理者在 Sinorhizobium meliloti 由 transcriptional 管理者的第二个最大的家庭组成，很少对他们的功能被知道。在这研究，我们调查了把 transcriptional 管理者的 GntR 家庭编码为 S 的 54 通常认为的基因。meliloti Rm1021。这些通常认为的 transcriptional 管理者的 C 终端领域的第二等的结构分析显示 37 是 FadR 亚科的成员，十个 HutC 亚科和五个 MocR 亚科。留下二没掉进任何特定的亚科范畴，并且可以形成二个新亚科。54 gntR 基因是由原生质标志插入傻瓜发育不全的 mutagenized 调查他们的角色。我们发现 54 异种，仅仅 gtrA1 和 gtrB1 异种有更慢的生长率和房间中等、最小的富人上的最大的收益聚集的板上的中等、更低的房间活动性比野类型 Rm1021。与 gtrA1 和 gtrB1 的例外，所有异种能与苜蓿建立有效 symbioses。与 gtrA1 和 gtrB1 异种接种的植物变得比与野类型接种的那些短，并且形成了相对更小、圆、轻的粉红色的小瘤，它主要位于侧面的根。并且两异种导致的小瘤的数字有反常增加。这些结果建议 gtrA1 和 gtrB1 异种是共生的联盟者缺乏。我们的工作给出在 S 涉及共生的象 GntR 一样 transcriptional 管理者的全球概述。meliloti，并且提供新卓见进象 GntR 一样 transcriptional 管理者的功能。

英文摘要：

GntR-type transcriptional regulators regulate the most diverse biological processes in bacteria. Although GntR-type transcriptional regulators consist of the second largest family of transcriptional regulators in Sinorhizobium meliloti, little is known about their functions. In this study, we investigated 54 putative genes encoding GntR family of transcriptional regulators in S. meliloti Rm1021. Secondary structure analysis of the C-terminal domain of these putative transcriptional regulators indicated that thirty-seven were members of the FadR subfamily, ten of the HutC subfamily and five of the MocR subfamily. The remaining two did not fall into any specific subfamily category, and may form two new subfamilies. The 54 gntR genes were mutagenized by plasmid insertion mutagenesis to investigate their roles. We found that, of the 54 mutants, only the gtrA1 and gtrB1 mutants had slower growth rates and cell maximal yields on both rich medium and minimal medium, and lower cell motility on swarming plate than wild type Rm1021. All mutants, with the exception of gtrA1 and gtrB1, can establish effective symbioses with alfalfa. Plants inoculated with gtrA 1 and gtrB1 mutants grew shorter than those inoculated with wild type, and formed relatively smaller, round and light pink nodules, which were mainly located on lateral roots. And there was an abnormal increase in the number of nodules induced by both mutants. These results suggested that the gtrA1 and gtrB1 mutants were symbiotically deficient. Our work presents a global overview of GntR-like transcriptional regulators involved in symbiosis in S. meliloti, and provides new insight into the functions of GntR-like transcriptional regulators.