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Identification and characterization of new LuxR/LuxI‐type quorum sensing systems from metagenomic libraries
Author(s) -
Hao Youai,
Winans Stephen C.,
Glick Bernard R.,
Charles Trevor C.
Publication year - 2010
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2009.02049.x
Subject(s) - quorum sensing , biology , metagenomics , cosmid , chromobacterium violaceum , gene , genetics , virulence
Summary Quorum sensing (QS) cell–cell communication systems are utilized by bacteria to coordinate their behaviour according to cell density. Several different types of QS signal molecules have been identified, among which acyl‐homoserine lactones (AHLs) produced by Proteobacteria have been studied to the greatest extent. Although QS has been studied extensively in cultured microorganisms, little is known about the QS systems of uncultured microorganisms and the roles of these systems in microbial communities. To extend our knowledge of QS systems and to better understand the signalling that takes place in the natural environment, metagenomic libraries constructed using DNA from activated sludge and soil were screened, using an Agrobacterium biosensor strain, for novel QS synthase genes. Three cosmids (QS6‐1, QS10‐1 and QS10‐2) that encode the production of QS signals were identified and DNA sequence analysis revealed that all three clones encode a novel luxI family AHL synthase and a luxR family transcriptional regulator. Thin layer chromatography revealed that these LuxI homologue proteins are able to synthesize multiple AHL signals. Tandem mass spectrometry analysis revealed that LuxI QS6‐1 directs the synthesis of at least three AHLs, 3‐O‐C14:1 HSL, 3‐O‐C16:1 HSL and 3‐O‐C14 HSL; LuxI QS10‐1 directs the synthesis of at least 3‐O‐C12 HSL and 3‐O‐C14 HSL; while LuxI QS10‐2 directs the synthesis of at least C8 HSL and C10 HSL. Two possible new AHLs, C14:3 HSL and (?)‐hydroxymethyl‐3‐O‐C14 HSL, were also found to be synthesized by LuxI QS6‐1 .