A novel two‐component system modulates quorum sensing and pathogenicity in <i>Burkholderia cenocepacia</i>

Cui, Chaoyu; Yang, Chunxi; Song, Shihao; Fu, Shuna; Sun, Xiaoning; Yang, Liang; He, Fei; Zhang, Lian-Hui; Zhang, Yongliang; Deng, Yinyue

doi:10.1111/mmi.13915

Cited by 32 publications

(42 citation statements)

References 43 publications

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“…RT‐qPCR was carried out as described in previous studies (Cui et al , 2018). The bacterial cells were collected when the cell optical density (OD 600 ) reached 1.0 in NYG medium.…”

Section: Methodsmentioning

confidence: 99%

RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris

Liao

et al. 2020

Molecular Plant Pathology

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Homologous regulatory factors are widely present in bacteria, but whether homologous regulators synergistically or differentially regulate different biological functions remains mostly unknown. Here, we report that the homologous regulators RpoN1 and RpoN2 of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) play different regulatory roles with respect to virulence traits, flagellar biosynthesis, and basal metabolism. RpoN2 directly regulated Xcc fliC and fliQ to modulate flagellar synthesis in X. campestris, thus affecting the swimming motility of X. campestris.Mutation of rpoN2 resulted in reduced production of biofilms and extracellular polysaccharides in Xcc. These defects may together cause reduced virulence of the rpoN2 mutant against the host plant. Moreover, we demonstrated that RpoN1 could regulate branched-chain fatty acid production and modulate the synthesis of diffusible signal factor family quorum sensing signals. Although RpoN1 and RpoN2 are homologues, the regulatory roles and biological functions of these proteins were not interchangeable. Overall, our report provides new insights into the two different molecular roles that form the basis for the transcriptional specialization of RpoN homologues. K E Y W O R D S flagellar synthesis, sigma factor 54 RpoN, virulence, Xanthomonas campestris pv. campestris S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section.

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“…RT‐qPCR was carried out as described in previous studies (Cui et al , 2018). The bacterial cells were collected when the cell optical density (OD 600 ) reached 1.0 in NYG medium.…”

Section: Methodsmentioning

confidence: 99%

RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris

Liao

et al. 2020

Molecular Plant Pathology

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“…The ethyl acetate was collected and evaporated to dryness and dissolved in 1 ml of methanol. BDSF signals were measured by liquid chromatography-mass spectrometry (LC-MS) (33).…”

Section: Methodsmentioning

confidence: 99%

“…qRT-PCR was performed using SYBR green qPCR mastermixes (Thermo Scientific) and a 7300Plus real-time PCR system (Applied Biosystems). The recA gene was used as an internal reference (33). The relative expression levels of the target genes were calculated using the quantitation-comparative C T (ΔΔC T ) method according to Livak and Schmittgen (45).…”

Section: Methodsmentioning

confidence: 99%

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Disruption of Quorum Sensing and Virulence in Burkholderia cenocepacia by a Structural Analogue of the cis -2-Dodecenoic Acid Signal

Cui

Song

Yang

et al. 2019

Appl Environ Microbiol

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Quorum sensing (QS) signals are widely used by bacterial pathogens to control biological functions and virulence in response to changes in cell population densities. Burkholderia cenocepacia employs a molecular mechanism in which the cis-2-dodecenoic acid (named Burkholderia diffusible signal factor [BDSF]) QS system regulates N-acyl homoserine lactone (AHL) signal production and virulence by modulating intracellular levels of cyclic diguanosine monophosphate (c-di-GMP). Thus, inhibition of BDSF signaling may offer a non-antibiotic-based therapeutic strategy against BDSF-regulated bacterial infections. In this study, we report the synthesis of small-molecule mimics of the BDSF signal and evaluate their ability to inhibit BDSF QS signaling in B. cenocepacia. A novel structural analogue of BDSF, 14-Me-C 16:Δ2 (cis-14-methylpentadec-2-enoic acid), was observed to inhibit BDSF production and impair BDSF-regulated phenotypes in B. cenocepacia, including motility, biofilm formation, and virulence, while it did not inhibit the growth rate of this pathogen. 14-Me-C 16:Δ2 also reduced AHL signal production. Genetic and biochemical analyses showed that 14-Me-C 16:Δ2 inhibited the production of the BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Notably, 14-Me-C 16:Δ2 attenuated BDSF-regulated phenotypes in various Burkholderia species. These findings suggest that 14-Me-C 16:Δ2 could potentially be developed as a new therapeutic agent against pathogenic Burkholderia species by interfering with their QS signaling. IMPORTANCE Burkholderia cenocepacia is an important opportunistic pathogen which can cause life-threatening infections in susceptible individuals, particularly in cystic fibrosis and immunocompromised patients. It usually employs two types of quorum sensing (QS) systems, including the cis-2-dodecenoic acid (BDSF) system and N-acyl homoserine lactone (AHL) system, to regulate virulence. In this study, we have designed and identified an unsaturated fatty acid compound (cis-14-methylpentadec-2enoic acid [14-Me-C 16:Δ2 ]) that is capable of interfering with B. cenocepacia QS signaling and virulence. We demonstrate that 14-Me-C 16:Δ2 reduced BDSF and AHL signal production in B. cenocepacia. It also impaired QS-regulated phenotypes in various Burkholderia species. These results suggest that 14-Me-C 16:Δ2 could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.

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“…A single-crossover integrant colony was spread on LB medium without gentamycin and incubated at 28°C for 3 days, and after appropriate dilution the culture was spread on LB plates containing 15% sucrose. Colonies sensitive to gentamycin were screened by PCR using the primers listed in Table 3, and the Le rpfB1 Quantitative real-time PCR was carried out according to previous studies (40). The bacterial cells were collected when the cellular optical density (OD600) reached 1.0 in 10% TSB.…”

Section: Deletion Of Le Rpfbs and Complementationmentioning

confidence: 99%

Two Functional Fatty Acyl Coenzyme A Ligases Affect Free Fatty Acid Metabolism To Block Biosynthesis of an Antifungal Antibiotic in Lysobacter enzymogenes

Hou

et al. 2020

Appl Environ Microbiol

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In Lysobacter enzymogenes OH11, RpfB1 and RpfB2 were predicted to encode acyl coenzyme A (CoA) ligases. RpfB1 is located in the Rpf gene cluster. Interestingly, we found an RpfB1 homolog (RpfB2) outside this canonical gene cluster, and nothing is known about its functionality or mechanism. Here, we report that rpfB1 and rpfB2 can functionally replace EcFadD in the Escherichia coli fadD mutant JW1794. RpfB activates long-chain fatty acids (n-C16:0 and n-C18:0) for the corresponding fatty acyl-CoA ligase (FCL) activity in vitro, and Glu-361 plays critical roles in the catalytic mechanism of RpfB1 and RpfB2. Deletion of rpfB1 and rpfB2 resulted in significantly increased heat-stable antifungal factor (HSAF) production, and overexpression of rpfB1 or rpfB2 completely suppressed HSAF production. Deletion of rpfB1 and rpfB2 resulted in increased L. enzymogenes diffusible signaling factor 3 (LeDSF3) synthesis in L. enzymogenes. Overall, our results showed that changes in intracellular free fatty acid levels significantly altered HSAF production. Our report shows that intracellular free fatty acids are required for HSAF production and that RpfB affects HSAF production via FCL activity. The global transcriptional regulator Clp directly regulated the expression of rpfB1 and rpfB2. In conclusion, these findings reveal new roles of RpfB in antibiotic biosynthesis in L. enzymogenes. IMPORTANCE Understanding the biosynthetic and regulatory mechanisms of heat-stable antifungal factor (HSAF) could improve the yield in Lysobacter enzymogenes. Here, we report that RpfB1 and RpfB2 encode acyl coenzyme A (CoA) ligases. Our research shows that RpfB1 and RpfB2 affect free fatty acid metabolism via fatty acyl-CoA ligase (FCL) activity to reduce the substrate for HSAF synthesis and, thereby, block HSAF production in L. enzymogenes. Furthermore, these findings reveal new roles for the fatty acyl-CoA ligases RpfB1 and RpfB2 in antibiotic biosynthesis in L. enzymogenes. Importantly, the novelty of this work is the finding that RpfB2 lies outside the Rpf gene cluster and plays a key role in HSAF production, which has not been reported in other diffusible signaling factor (DSF)/Rpf-producing bacteria.

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A novel two‐component system modulates quorum sensing and pathogenicity in Burkholderia cenocepacia

Cited by 32 publications

References 43 publications

RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris

RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris

Disruption of Quorum Sensing and Virulence in Burkholderia cenocepacia by a Structural Analogue of the cis -2-Dodecenoic Acid Signal

Two Functional Fatty Acyl Coenzyme A Ligases Affect Free Fatty Acid Metabolism To Block Biosynthesis of an Antifungal Antibiotic in Lysobacter enzymogenes

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