Quorum Sensing Controls the CRISPR and Type VI Secretion Systems in Aliivibrio wodanis 06/09/139
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https://hdl.handle.net/10037/25110Date
2022-02-22Type
Journal articleTidsskriftartikkel
Peer reviewed
Abstract
For bacteria to thrive in an environment with competitors, phages and environmental
cues, they use different strategies, including Type VI Secretion Systems (T6SSs) and
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) to compete
for space. Bacteria often use quorum sensing (QS), to coordinate their behavior as
the cell density increases. Like other aliivibrios, Aliivibrio wodanis 06/09/139 harbors
two QS systems, the main LuxS/LuxPQ system and an N-acyl homoserine lactone
(AHL)-mediated AinS/AinR system and a master QS regulator, LitR. To explore the QS
and survival strategies, we performed genome analysis and gene expression profiling
on A. wodanis and two QS mutants (1ainS and 1litR) at two cell densities (OD600 2.0
and 6.0) and temperatures (6 and 12◦C). Genome analysis of A. wodanis revealed two
CRISPR systems, one without a cas loci (CRISPR system 1) and a type I-F CRISPR
system (CRISPR system 2). Our analysis also identified three main T6SS clusters (T6SS1,
T6SS2, and T6SS3) and four auxiliary clusters, as well about 80 potential Type VI
secretion effectors (T6SEs). When comparing the wildtype transcriptome data at different
cell densities and temperatures, 13–18% of the genes were differentially expressed. The
CRISPR system 2 was cell density and temperature-independent, whereas the CRISPR
system 1 was temperature-dependent and cell density-independent. The primary and
auxiliary clusters of T6SSs were both cell density and temperature-dependent. In the
1litR and 1ainS mutants, several CRISPR and T6SS related genes were differentially
expressed. Deletion of litR resulted in decreased expression of CRISPR system 1 and
increased expression of CRISPR system 2. The T6SS1 and T6SS2 gene clusters were
less expressed while the T6SS3 cluster was highly expressed in 1litR. Moreover, in 1litR,
the hcp1 gene was strongly activated at 6◦C compared to 12◦C. AinS positively affected
the csy genes in the CRISPR system 2 but did not affect the CRISPR arrays. Although
AinS did not significantly affect the expression of T6SSs, the hallmark genes of T6SS
(hcp and vgrG) were AinS-dependent. The work demonstrates that T6SSs and CRISPR
systems in A. wodanis are QS dependent and may play an essential role in survival in its
natural environment.
Is part of
Maharajan, A.D. (2023). AHL-mediated quorum sensing regulation: Role in controlling cytotoxicity, T6SSs and CRISPR-Cas systems in Aliivibrio wodanis. (Doctoral thesis). https://hdl.handle.net/10037/28075Publisher
Frontiers MediaCitation
Maharajan, Hjerde, Hansen, Willassen. Quorum Sensing Controls the CRISPR and Type VI Secretion Systems in Aliivibrio wodanis 06/09/139. Frontiers in Veterinary Science. 2022Metadata
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