Specific gamma-aminobutyrate chemotaxis in pseudomonads with different lifestyle
Specific gamma-aminobutyrate chemotaxis in pseudomonads with different lifestyle
复制标题
DOI：
10.1111/mmi.13045
复制
发表时间：
2015-08-01
影响因子：
3.6
通讯作者：
Krell, Tino
中科院分区：
文献类型：
--
作者：
Antonio Reyes-Darias, Jose;Garcia, Vanina;Krell, Tino
铜绿假单胞菌的PCTC化学受体介导对γ-氨基丁酸(GABA)高度特异的趋化作用。这种化合物在自然界中无处不在，具有多种功能，包括作为人类神经递质或植物信号化合物。由于铜绿假单胞菌在自然界中广泛分布，能够感染和定植不同的宿主，因此GABA趋向性的生理相关性尚不清楚，但已有研究表明，细菌对神经递质的吸引可能会增强毒力。在非致病性恶臭假单胞菌KT2440中，我们发现McpG是一种特异性的GABA化学受体。与PCTC一样，GABA被发现与McpG紧密结合。对融合到Tar信号域的PCTC和McpG配体结合域的嵌合体的分析表明，GABA具有很高的灵敏度。我们还表明，PCTC灭活不会改变秀丽线虫的毒力。在番茄根分泌物中检测到大量的GABA，mcpG的缺失减少了根的定植，这需要通过琼脂进行趋化。秀丽线虫的数据和在非致病物种中检测到的GABA受体表明，GABA趋向性可能与动物系统的毒力无关，但在土壤假单胞菌侵染植物根部的背景下可能是重要的。
The PctC chemoreceptor of Pseudomonas aeruginosa mediates chemotaxis with high specificity to gamma-aminobutyric acid (GABA). This compound is present everywhere in nature and has multiple functions, including being a human neurotransmitter or plant signaling compound. Because P.aeruginosa is ubiquitously distributed in nature and able to infect and colonize different hosts, the physiological relevance of GABA taxis is unclear, but it has been suggested that bacterial attraction to neurotransmitters may enhance virulence. We report the identification of McpG as a specific GABA chemoreceptor in non-pathogenic Pseudomonas putidaKT2440. As with PctC, GABA was found to bind McpG tightly. The analysis of chimeras comprising the PctC and McpG ligand-binding domains fused to the Tar signaling domain showed very high GABA sensitivities. We also show that PctC inactivation does not alter virulence in Caenorhabditis elegans. Significant amounts of GABA were detected in tomato root exudates, and deletion of mcpG reduced root colonization that requires chemotaxis through agar. The C.elegans data and the detection of a GABA receptor in non-pathogenic species indicate that GABA taxis may not be related to virulence in animal systems but may be of importance in the context of colonization and infection of plant roots by soil-dwelling pseudomonads.