Multiple N-acyl homoserine lactone signals of Rhizobium leguminosarum are synthesized in a distinct temporal pattern
Multiple N-acyl homoserine lactone signals of Rhizobium leguminosarum are synthesized in a distinct temporal pattern
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DOI：
10.1128/jb.183.23.6771-6777.2001
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发表时间：
2001-12-01
影响因子：
3.2
通讯作者：
Gray, KM
中科院分区：
文献类型：
--
作者：
Blosser-Middleton, RS;Gray, KM
细菌群体感应的一种常见形式涉及酰基高丝氨酸内酯（阿勒）信号代谢物的产生和释放。据报道，固氮共生菌根瘤菌豆类产生至少六种不同的AHLs，但很少有人知道这些分子的生物合成的调控。我们使用放射性标记的协议，以定量的相对数量的AHLs合成随着时间的推移，由R。用和不用共生质粒pRLIJI的豆科植物细胞。发现含有pRLIJI的细胞产生三种主要信号。按丰度降序排列，它们是N-（3-氧代）辛酰基高丝氨酸内酯[（3-O）C8 HSL]、N-辛酰基高丝氨酸内酯和N-己酰基高丝氨酸内酯。没有pRLIJI的细胞仅产生两种主要信号，N-（3-羟基，7-顺式）十四酰基高丝氨酸内酯[（3-OH）C1.4：1HSL]和（3-O）C8 HSL。每个阿勒表现出不同的时间模式的合成，这表明每个阿勒是受独特的调节机制。虽然（3-O）C8 HSL在两种培养物中产生，但在有和没有pRLIJI的细胞中合成模式不同，这可能是染色体和共生质粒上存在的冗余基因功能的结果。尽管外源性（3-OH）C1.4：1HSL确实激活了含有pRLIJI的细胞所产生的三种NHL的合成，但没有一种AHLs似乎调节其自身的生物合成。这些结果表明，多个AHLs在R.豆类是由复杂的机制，独立于群体感应本身的运作，但（3-OH）C14：1HSL可以取代这些控制在含有pRLIJI的细胞。这项工作为阿勒调控提供了一个重要的全球视角，与以前用分离的基因系统进行的研究结果形成了互补和对比。
A common form of bacterial quorum sensing involves the production and release of acyl homoserine lactone (AHL) signal metabolites. The nitrogen-fixing symbiont Rhizobium leguminosarum reportedly produces at least six different AHLs, but little is known about the regulation of biosynthesis of these molecules. We used a radiolabeling protocol to quantify the relative amounts of AHLs synthesized over time by R. leguminosarum cells with and without the symbiosis plasmid pRLIJI. Cells containing pRLIJI were found to produce three predominant signals. In decreasing order of abundance,, these were N-(3-oxo)octanoyl homoserine lactone [(3-O)C8HSL], N-octanoyl homoserine lactone, and N-hexanoyl homoserine lactone. Cells without pRLIJI produced only two major signals, N-(3-hydroxy,7-cis)tetradecanoyl homoserine lactone [(3-OH)C1.4:1HSL] and (3-O)C8HSL. Each AHL exhibited a distinct temporal pattern of synthesis, suggesting that each AHL is subject to unique regulatory mechanisms. While (3-O)C8HSL was produced in both cultures, the patterns of synthesis were different in cells with and without pRLIJI, possibly as a result of redundant gene functions that are present on both the chromosome and the symbiosis plasmid. None of the AHLs appeared to regulate its own biosynthesis, although exogenous (3-OH)C1.4:1HSL did activate synthesis of the three NHLs made by cells containing pRLIJI. These results indicate that the synthesis of multiple AHLs in R. leguminosarum is regulated by complex mechanisms that operate independently of quorum sensing itself but that (3-OH)C14:1HSL can supersede these controls in pRLIJI-containing cells. This,work provides an important global perspective for AHL regulation that both complements and contrasts with the results of previous studies performed with isolated gene systems.