AUTHOR=Zeng Yanhua , Wang Yanli , Yu Zhiliang , Huang Yili 

TITLE=Hypersensitive Response of Plasmid-Encoded AHL Synthase Gene to Lifestyle and Nutrient by Ensifer adhaerens X097

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01160

DOI=10.3389/fmicb.2017.01160

ISSN=1664-302X

ABSTRACT=<p>It is known that some bacteria, especially members of the family <italic>Rhizobiaceae</italic>, have multiple <italic>N</italic>-acyl homoserine lactones (AHL) synthase genes and produce multiple AHL signals. However, how bacteria selectively utilize these multiple genes and signals to cope with changing environments is poorly understood. <italic>Ensifer adhaerens</italic> is an important microorganism in terms of biotechnology, ecology and evolutionary. In this study, we investigated the AHL-based QS system of <italic>E. adhaerens</italic> X097 and its response to different lifestyles or nutrients. Draft genome sequence data indicated that X097 harbored three distinct AHL synthase genes (<italic>ensI1, 2, 3</italic>) and seven <italic>luxR</italic> homologs, which was different from other <italic>E. adhaerens</italic> strains. <italic>In vitro</italic> expression indicated that plasmid-encoded <italic>ensI1</italic> and <italic>ensI2</italic> directed production of multiple AHLs, while chromosome-encoded <italic>ensI3</italic> only directed production of C14-HSL. Predicted three dimensional structure of EnsI3 was quite different from that of EnsI1 and EnsI2. X097 produced different AHL profiles in Luria-Bertani (LB) and NFB medium, under biofilm and planktonic lifestyle, respectively. Notably, expression of <italic>ensI1</italic> and <italic>ensI2</italic> but not <italic>ensI3</italic> is hypersensitive to different lifestyles and nutrients. The hypersensitive response of plasmid-encoded AHL synthase genes to different culture conditions may shed a light on the phylogenetic development of AHL synthase genes in <italic>Rhizobiaceae</italic> family.</p>