Characterization of a diffusible signaling factor from Xylella fastidiosa.
Characterization of a diffusible signaling factor from Xylella fastidiosa.
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DOI：
10.1128/mbio.00539-12
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发表时间：
2013-01-08
期刊：
影响因子：
6.4
通讯作者：
Lindow S
中科院分区：
文献类型：
--
作者：
Beaulieu ED;Ionescu M;Chatterjee S;Yokota K;Trauner D;Lindow S
苛养木杆菌中的细胞-细胞信号转导与植物宿主和昆虫载体中能够定殖的性状的协调有关。这种细胞密度依赖性信号传导归因于由DSF合酶RpfF产生的可扩散信号传导因子（DSF）。相关细菌产生的DSF是不饱和脂肪酸，但苛养木杆菌的DSF被认为不同于其他类群。本文描述了苛养木杆菌DSF（XfDSF）作为2（Z）-十四烯酸的分离和表征。该化合物从表达苛养木杆菌rpfF的重组草生欧文氏菌和过量产生DSF的苛养木杆菌rpfC缺失突变体中分离得到。由于rpfF突变体在生物膜形成中受损，并且低表达血凝素样蛋白编码基因hxfA和hxfB，因此我们证明这些特征可以通过ca恢复。0.5µM XfDSF，但不被肉豆蔻酸，完全饱和的十四烯酸。基于phoA的苛养木杆菌生物传感器评估hxfA或hxfB的DSF依赖性表达，揭示了DSF信号传导的高水平分子特异性。苛养木蠹蛾在许多重要植物中引起疾病，包括葡萄，在那里它引发皮尔斯病。苛养木霉菌对葡萄的毒力是由细胞间信号分子DSF（Diffusible Signaling Factor）协调的。在DSF生产中被阻断的突变体对葡萄是高毒性的，这表明DSF积累后毒性被抑制，并且可以通过人工升高植物中的DSF水平来控制疾病。在这项工作中，我们描述了分离的DSF产生的苛养木杆菌和验证其生物活性作为一种抗毒力因子。我们还开发了苛养木杆菌DSF生物传感器，以评估待研究的细胞-细胞信号传导的特异性。
Cell-cell signaling in Xylella fastidiosa has been implicated in the coordination of traits enabling colonization in plant hosts as well as insect vectors. This cell density-dependent signaling has been attributed to a diffusible signaling factor (DSF) produced by the DSF synthase RpfF. DSF produced by related bacterial species are unsaturated fatty acids, but that of X. fastidiosa was thought to be different from those of other taxa. We describe here the isolation and characterization of an X. fastidiosa DSF (XfDSF) as 2(Z)-tetradecenoic acid. This compound was isolated both from recombinant Erwinia herbicola expressing X. fastidiosa rpfF and from an X. fastidiosa rpfC deletion mutant that overproduces DSF. Since an rpfF mutant is impaired in biofilm formation and underexpresses the hemagglutinin-like protein-encoding genes hxfA and hxfB, we demonstrate that these traits can be restored by ca. 0.5 µM XfDSF but not by myristic acid, the fully saturated tetradecenoic acid. A phoA-based X. fastidiosa biosensor that assesses DSF-dependent expression of hxfA or hxfB revealed a high level of molecular specificity of DSF signaling. X. fastidiosa causes diseases in many important plants, including grape, where it incites Pierce’s disease. Virulence of X. fastidiosa for grape is coordinated by cell-cell signaling molecules, designated DSF (Diffusible Signaling Factor). Mutants blocked in DSF production are hypervirulent for grape, suggesting that virulence is suppressed upon DSF accumulation and that disease could be controlled by artificial elevation of the DSF level in plants. In this work, we describe the isolation of the DSF produced by X. fastidiosa and the verification of its biological activity as an antivirulence factor. We also have developed X. fastidiosa DSF biosensors to evaluate the specificity of cell-cell signaling to be investigated.