The stringent response promotes biofilm dispersal in Pseudomonas putida.
The stringent response promotes biofilm dispersal in Pseudomonas putida.
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DOI：
10.1038/s41598-017-18518-0
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发表时间：
2017-12-22
影响因子：
4.6
通讯作者：
Govantes F
中科院分区：
文献类型：
--
作者：
Díaz-Salazar C;Calero P;Espinosa-Portero R;Jiménez-Fernández A;Wirebrand L;Velasco-Domínguez MG;López-Sánchez A;Shingler V;Govantes F
生物膜扩散是一种遗传程序化的反应，使细菌细胞能够响应特定的生理或环境条件而离开生物膜。在恶臭假单胞菌生物膜中，营养物饥饿通过磷酸二酯酶BifA触发c-di-GMP水解，通过c-di-GMP效应蛋白LapD释放蛋白酶LapG的抑制，并导致粘附素LapA的蛋白水解和随后的生物膜细胞的释放。在这里，我们表明，严格的反应，一个无处不在的细菌应激反应，是负责中继营养应激信号的生物膜分散机械。缺乏严格响应元件的突变体-（p）ppGpp合成酶[RelA和SpoT]和/或DksA -在生物膜分散中是有缺陷的。异位（p）ppGpp合成恢复生物膜分散在一个EscherelA EscherspoT突变体。体内基因表达分析表明，（p）ppGpp正调控bifA的转录，负调控lapA和lapBC和lapE操纵子的转录，编码LapA特异性分泌系统。进一步的体内和体外表征表明，PbifA启动子依赖于鞭毛σ因子FliA，并受到ppGpp和DksA的正调控。我们的研究结果表明，严格的反应刺激生物膜分散营养限制下协调促进LapA蛋白水解和防止从头LapA的合成和分泌。
Biofilm dispersal is a genetically programmed response enabling bacterial cells to exit the biofilm in response to particular physiological or environmental conditions. In Pseudomonas putida biofilms, nutrient starvation triggers c-di-GMP hydrolysis by phosphodiesterase BifA, releasing inhibition of protease LapG by the c-di-GMP effector protein LapD, and resulting in proteolysis of the adhesin LapA and the subsequent release of biofilm cells. Here we demonstrate that the stringent response, a ubiquitous bacterial stress response, is accountable for relaying the nutrient stress signal to the biofilm dispersal machinery. Mutants lacking elements of the stringent response – (p)ppGpp sythetases [RelA and SpoT] and/or DksA – were defective in biofilm dispersal. Ectopic (p)ppGpp synthesis restored biofilm dispersal in a ∆relA ∆spoT mutant. In vivo gene expression analysis showed that (p)ppGpp positively regulates transcription of bifA, and negatively regulates transcription of lapA and the lapBC, and lapE operons, encoding a LapA-specific secretion system. Further in vivo and in vitro characterization revealed that the PbifA promoter is dependent on the flagellar σ factor FliA, and positively regulated by ppGpp and DksA. Our results indicate that the stringent response stimulates biofilm dispersal under nutrient limitation by coordinately promoting LapA proteolysis and preventing de novo LapA synthesis and secretion.
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影响因子：
3.6
作者：
Aberg, Anna;Shingler, Victoria;Balsalobre, Carlos
通讯作者：
Balsalobre, Carlos
影响因子：
48
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Choi, KH;Gaynor, JB;Schweizer, HP
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Schweizer, HP
影响因子：
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影响因子：
4.4
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An, Shuwen;Wu, Ji'en;Zhang, Lian-Hui
通讯作者：
Zhang, Lian-Hui
影响因子：
3.6
作者：
Aberg, Anna;Shingler, Victoria;Balsalobre, Carlos
通讯作者：
Balsalobre, Carlos