Shewanella oneidensis MR‐1 was cultured on electrodes in electrochemical flow cells (EFCs), and transcriptome profiles of electrode‐attached cells grown under electrolyte‐flow conditions were compared with those under static (nonflow) conditions. Results revealed that, along with genes related to c‐type cytochrome maturation (e.g., dsbD), the SO_3096 gene encoding a putative extracytoplasmic function (ECF) sigma factor was significantly upregulated under electrolyte‐flow conditions. Compared to wild‐type MR‐1 (WT), an SO_3096‐deletion mutant (∆SO_3096) showed impaired biofilm formation and decreased current generation in EFCs, suggesting that SO_3096 plays critical roles in the interaction of MR‐1 cells with electrodes under electrolyte‐flow conditions. We also compared transcriptome profiles of WT and ∆SO_3096 grown in EFCs, confirming that many genes upregulated under the electrolyte‐flow conditions, including dsbD, are regulated by SO_3096. LacZ reporter assays showed that transcription from a promoter upstream of dsbD is activated by SO_3096. Measurement of current generated by a dsbD‐deletion mutant revealed that this gene is essential for the transfer of electrons to electrodes. These results indicate that the SO_3096 gene product facilitates c‐type cytochrome maturation and current generation under electrolyte‐flow conditions. The results also offer ecophysiological insights into how Shewanella regulates extracellular electron transfer to solid surfaces in the natural environment.

中文翻译：

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鉴定胞外功能sigma因子，该因子促进Shewanella oneidensis MR-1中在电解质流动条件下的c型细胞色素成熟和电流产生。

将Shewanella oneidensis MR-1培养在电化学流通池（EFC）的电极上，并将在电解质流条件下生长的电极附着细胞的转录组谱与静态（非流动）条件下的转录组谱进行比较。结果显示，与c型细胞色素成熟相关的基因（例如dsbD），在电解质流动条件下，编码推定胞浆外功能（ECF）σ因子的SO_3096基因显着上调。与野生型MR-1（WT）相比，SO_3096缺失突变体（∆SO_3096）在EFC中显示出生物膜形成受损和电流生成减少的现象，这表明SO_3096在MR-1细胞与电解质下的电极相互作用中起关键作用流动条件。我们还比较了在EFC中生长的WT和∆SO_3096的转录组图谱，确认了在电解质流动条件下上调的许多基因，包括dsbD，都受到SO_3096的调控。LacZ记者分析表明，SO_3096激活了dsbD上游启动子的转录。测量dsbD产生的电流删除突变表明该基因对于电子转移至电极至关重要。这些结果表明，SO_3096基因产物在电解质流动条件下促进c型细胞色素成熟和电流产生。研究结果还为希瓦氏菌如何调节自然环境中细胞外电子向固体表面的转移提供了生态生理学见解。