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DqsIR quorum sensing‐mediated gene regulation of the extremophilic bacterium D einococcus radiodurans in response to oxidative stress
Author(s) -
Lin Lin,
Dai Shang,
Tian Bing,
Li Tao,
Yu Jiangliu,
Liu Chengzhi,
Wang Liangyan,
Xu Hong,
Zhao Ye,
Hua Yuejin
Publication year - 2016
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.13331
Subject(s) - quorum sensing , biology , deinococcus radiodurans , mutant , gene , oxidative stress , bacteria , microbiology and biotechnology , biofilm , genetics , biochemistry
Summary Here, we show that AHLs can be employed by Deinococcus radiodurans , which belongs to the unique phylum Deinococcus‐Thermus and is known for its cellular resistance to environmental stresses. An AHL‐mediated quorum‐sensing system (DqsI/DqsR) was identified in D. radiodurans . We found that under non‐stress conditions, the AHL level was “shielded” by quorum quenching enzymes, whereas AHLs accumulated when D. radiodurans was exposed to oxidative stress. Upon exposure to H 2 O 2 , AHL synthetic enzymes (DqsI) were immediately induced, while the expression of quorum‐quenching enzymes began to increase approximately 30 min after exposure to H 2 O 2 , as shown by time‐course analyses of gene expression. Both dqsI mutant (DMDqsI) and dqsR mutant (MDqsR) were more sensitive to oxidative stress compared with the wild‐type strain. Exogenous AHLs (5 μM) could completely restore the survival fraction of DMDqsI under oxidative stress. RNA‐seq analysis showed that a number of genes involved in stress‐response, cellular cleansing, and DNA repair had altered transcriptional levels in MDqsR. The DqsR, acting as a regulator of quorum sensing, controls gene expression along with AHLs. Hence, the DqsIR‐mediated quorum sensing that mediates gene regulation is an adaptive strategy for D. radiodurans in response to oxidative stresses and is conserved in the extremophilic Deinococcus bacteria.