Assessment of the contribution of chemoreceptor-based signalling to biofilm formation

作者：Corral Lugo Andres; De la Torre Jesus; Matilla Miguel A; Fernandez Matilde; Morel Bertrand; Espinosa Urgel Manuel; Krell Tino

来源：Environmental Microbiology, 2016, 18(10): 3355-3372.

DOI：10.1111/1462-2920.13170

<jats:title>Summary</jats:title><jats:p>Although it is well established that one‐ and two‐component regulatory systems participate in regulating biofilm formation, there also exists evidence suggesting that chemosensory pathways are also involved. However, little information exists about which chemoreceptors and signals modulate this process. Here we report the generation of the complete set of chemoreceptor mutants of <jats:styled-content style="fixed-case"><jats:italic>P</jats:italic></jats:styled-content><jats:italic>seudomonas putida</jats:italic> <jats:styled-content style="fixed-case">KT2440</jats:styled-content> and the identification of four mutants with significantly altered biofilm phenotypes. These receptors are a <jats:styled-content style="fixed-case">WspA</jats:styled-content> homologue of <jats:styled-content style="fixed-case"><jats:italic>P</jats:italic></jats:styled-content><jats:italic>seudomonas aeruginosa</jats:italic>, previously identified to control biofilm formation by regulating c‐di‐<jats:styled-content style="fixed-case">GMP</jats:styled-content> levels, and three uncharacterized chemoreceptors. One of these receptors, named <jats:styled-content style="fixed-case">McpU</jats:styled-content>, was found to mediate chemotaxis towards different polyamines. The functional annotation of <jats:styled-content style="fixed-case">McpU</jats:styled-content> was initiated by high‐throughput thermal shift assays of the receptor ligand binding domain (<jats:styled-content style="fixed-case">LBD</jats:styled-content>). Isothermal titration calorimetry showed that <jats:styled-content style="fixed-case">McpU</jats:styled-content>‐<jats:styled-content style="fixed-case">LBD</jats:styled-content> specifically binds putrescine, cadaverine and spermidine, indicating that <jats:styled-content style="fixed-case">McpU</jats:styled-content> represents a novel chemoreceptor type. Another uncharacterized receptor, named <jats:styled-content style="fixed-case">McpA</jats:styled-content>, specifically binds 12 different proteinogenic amino acids and mediates chemotaxis towards these compounds. We also show that mutants in <jats:styled-content style="fixed-case">McpU</jats:styled-content> and <jats:styled-content style="fixed-case">WspA</jats:styled-content>‐<jats:styled-content style="fixed-case">Pp</jats:styled-content> have a significantly reduced ability to colonize plant roots. Data agree with other reports showing that polyamines are signal molecules involved in the regulation of bacteria–plant communication and biofilm formation.</jats:p>

• 出版日期2016-10