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C omamonas testosteroni uses a chemoreceptor for tricarboxylic acid cycle intermediates to trigger chemotactic responses towards aromatic compounds
Author(s) -
Ni Bin,
Huang Zhou,
Fan Zheng,
Jiang ChengYing,
Liu ShuangJiang
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12400
Subject(s) - chemotaxis , biology , biochemistry , citric acid cycle , chemoreceptor , mutant , tricarboxylic acid , complementation , metabolism , receptor , gene
Summary Bacterial chemotaxis towards aromatic compounds has been frequently observed; however, knowledge of how bacteria sense aromatic compounds is limited. C omamonas testosteroni CNB ‐1 is able to grow on a range of aromatic compounds. This study investigated the chemotactic responses of CNB ‐1 to 10 aromatic compounds. We constructed a chemoreceptor‐free, non‐chemotactic mutant, CNB ‐1Δ20, by disruption of all 19 putative methyl‐accepting chemotaxis proteins ( MCPs ) and the atypical chemoreceptor in strain CNB ‐1. Individual complementation revealed that a putative MCP (tagged MCP 2201) was involved in triggering chemotaxis towards all 10 aromatic compounds. The recombinant sensory domain of MCP 2201 did not bind to 3‐ or 4‐hydroxybenzoate, protocatechuate, catechol, benzoate, vanillate and gentisate, but bound oxaloacetate, citrate, cis ‐aconitate, isocitrate, α‐ketoglutarate, succinate, fumarate and malate. The mutant CNB ‐1Δ pmdF that lost the ability to metabolize 4‐hydroxybenzoate and protocatechuate also lost its chemotactic response to these compounds, suggesting that taxis towards aromatic compounds is metabolism‐dependent. Based on the ligand profile, we proposed that MCP 2201 triggers taxis towards aromatic compounds by sensing TCA cycle intermediates. Our hypothesis was further supported by the finding that introduction of the previously characterized pseudomonad chemoreceptor ( McpS ) for TCA cycle intermediates into CNB ‐1Δ20 likewise triggered chemotaxis towards aromatic compounds.