Complementation analyses of Sinorhizobium meliloti nifA mutant with different originated nifA genes

推断的一个以前的工作 Enterobacter 下水道的 nifA 基因没恢复 Sinorhizobium meliloti nifA 的共生显型变异。在现在的学习， Bra-dyrhizobium 的 twonifA 基因日本嗯并且 Mesorhizobium huakuii 也没恢复 S 的共生显型。meliloti nifA 异种。在微数组试验的整个 genomic， 238 基因被发现是在 S 以后表示的差别。meliloti nifA 组成地在它的 nifAmutant 被表示了。相反，当表示 B.japonium 时，仅仅 20， 7 和 9 基因改变了他们的 transcriptional 层次， M。在 Sm nifA 异种的 huakuii 和 Enterobacter 下水道 nifA 基因独立。这些基因包括房子保留，精力和中央中间代谢被分类进几官能基，运输系统和共生。有趣地， nifHoperons，显示出的高表示面对任何一个 B 铺平的基因。japonium 或 M。huakuii NifA，它被随后的紫胶 Z 熔化实验证实。

A previous work inferred that the nifA gene of Enterobacter cloacae did not restore the symbiotic phenotype of Sinorhizobium meliloti nifA mutant. In the present study, two nifA genes of Bradyrhizobium japonicum and Mesorhizobium huakuii also did not restore the symbiotic phenotype of S. meliloti nifA mutant. In whole genomic microarray experiments, 238 genes were found to be differen- tially expressed after S. meliloti nifA had been constitutively expressed in its nifA mutant. In contrast, only 20, 7 and 9 genes changed their transcriptional levels when expressing B. japonium, M. huakuii and Enterobacter cloacae nifA genes in Sm nifA mutant, separately. These genes were classified into several functional groups including house keeping, energy and central intermediary metabolism, transport systems and symbiosis. Interestingly, the genes that of nifH operons showed high expression levels in the presence of either B. japonium or M. huakuii NifA, which was confirmed by subsequent lacZ fusion experiments.