Sinorhizobium meliloti nfe (nodulation formation efficiency) genes exhibit temporal and spatial expression patterns similar to those of genes involved in symbiotic nitrogen fixation
Sinorhizobium meliloti nfe (nodulation formation efficiency) genes exhibit temporal and spatial expression patterns similar to those of genes involved in symbiotic nitrogen fixation
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DOI：
10.1094/mpmi.2000.13.6.583
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发表时间：
2000-06-01
影响因子：
3.5
通讯作者：
Toro, N
中科院分区：
文献类型：
--
作者：
García-Rodríguez, FM;Toro, N
生命基因（nfeA、nfeB 和 nfeD）与苜蓿中华根瘤菌 GR4 菌株在苜蓿根上的结瘤效率和竞争力有关。 nfeA和nfeB基因前面是功能性nif共有序列和NifA结合基序，在这里，我们确定了与苜蓿共生的nfe基因的时间和空间表达模式，nfe启动子与gusA基因的翻译融合和逆转录聚合酶链反应分析表明它们在成熟的固氮模块中表达和翻译，而不是在根瘤发育的早期步骤中表达和翻译。在根瘤内，三个 nfe 基因表现出与参与共生固氮的基因相似的空间表达模式。我们发现 nfeB 和 nfeD 基因不仅从它们自己的启动子表达，而且从上游 nfe 启动子序列表达。此外，通过使用特异性抗体，在根瘤类菌部分中检测到了 NfeB 和 NfeD 蛋白。最后，NfeB 免疫定位于类菌细胞膜中，而 NfeD 在类菌细胞质中检测到。
The life genes (nfeA, nfeB, and nfeD) are involved in the nodulation efficiency and competitiveness of the Sinorhizobium meliloti strain GR4 on alfalfa roots. The nfeA and nfeB genes are preceded by functional nif consensus sequences and NifA binding motifs, Here, we determined the temporal and spatial expression patterns of the nfe genes in symbiosis with alfalfa, Translational fusions of the nfe promoters with the gusA gene and reverse transcription-polymerase chain reaction analyses indicate that they are expressed and translated within mature nitrogen-fixing modules and not during early steps of nodule development. Within the nodules the three nfe genes exhibit a spatial expression pattern similar to that of genes involved in symbiotic nitrogen fixation. We show that nfeB and nfeD genes are expressed not only from their own promoters but also from the upstream nfe promoter sequences. Furthermore, with the use of specific antibodies the NfeB and NfeD proteins were detected within the root nodule bacteroid fraction. Finally, NfeB was immunolocalized in the bacteroid cell membrane whereas NfeD was detected in the bacteroid cytoplasm.