Differential control of the PcoI/PcoR quorum-sensing system in Pseudomonas fluorescens 2P24 by sigma factor RpoS and the GacS/GacA two-component regulatory system.
Differential control of the PcoI/PcoR quorum-sensing system in Pseudomonas fluorescens 2P24 by sigma factor RpoS and the GacS/GacA two-component regulatory system.
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DOI：
10.1016/j.micres.2008.02.001
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发表时间：
2009
影响因子：
6.7
通讯作者：
Qing Yan;Xiaogang Wu;Hai-Lei Wei;Hui‐min Wang;Li-qun Zhang
中科院分区：
文献类型：
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作者：
Qing Yan;Xiaogang Wu;Hai-Lei Wei;Hui‐min Wang;Li-qun Zhang
在生防菌荧光假单胞菌2 P24中发现了一个群体感应（quorum-sensing，QS）位点PcoI/PcoR。在本文中，我们研究了上游调节器，影响转录的N-酰基高丝氨酸内酯（阿勒）生物合成酶基因pcoI使用染色体pcoI的paclacZ融合报告菌株。使用随机mini-Tn 5突变体程序将稳态σ因子RpoS鉴定为QS系统的负调节因子。此外，缺失突变和互补实验表明，双组分系统GacS/GacA正调控QS系统通过上调pcoI转录。然而，与gacA或gacS突变体相比，在gacA-或gacS-背景中引入rpoS的第二次突变并没有导致pcoI基因转录表达或阿勒合成的进一步变化。我们的结果表明，在菌株2 P24中，RpoS只能在功能性GacS/GacA系统背景下对pcoI基因发挥负调控作用。
A quorum-sensing (QS) locus PcoI/PcoR had been identified previously in the biological control bacterium Pseudomonas fluorescens 2P24. In this paper, we investigated the upstream regulators that influence the transcription of the N-acyl homoserine lactone (AHL) biosynthase gene pcoI using a chromosomal pcoI∷lacZ fusion reporter strain. Stationary sigma factor RpoS was identified as a negative regulator of QS system using a random mini-Tn5 mutant procedure. Furthermore, deletion mutagenesis and complementation experiments demonstrated that the two-component system GacS/GacA positively regulated the QS system by upregulating pcoI transcription. However, compared with the gacA or gacS mutant, introduction of a second mutation of rpoS in the gacA−or gacS−background did not lead to further change in the transcriptional expression of the pcoI gene or the synthesis of AHL. Our results suggest that in strain 2P24, RpoS could only play its negative regulatory role on the pcoI gene under a functional GacS/GacA system background.