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

Li, Kaihuai; Wu, Guichun; Liao, Y.P.; Zeng, Quan; Wang, Haihong; Liu, Fengquan

doi:10.1111/mpp.12938

Cited by 21 publications

(31 citation statements)

References 64 publications

(105 reference statements)

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“…The alternative sigma factor σ 54 was originally discovered in Salmonella as the sigma factor required for the synthesis of glutamine synthetase [41]. Subsequently, σ 54 was identified in a wide range of Gram-negative and Gram-positive bacteria, and found to play a general role in the control of nitrogen metabolism and to affect various other cellular functions such as motility, dicarboxylate transport, degradation of xenobiotics, and virulence in plant and human pathogens [42][43][44][45][46][47][48].…”

Section: Discussionmentioning

confidence: 99%

Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression

et al. 2020

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Rhizobia have two major life styles, one as free-living bacteria in the soil, and the other as bacteroids within the root/stem nodules of host legumes where they convert atmospheric nitrogen into ammonia. In the soil, rhizobia have to cope with changing and sometimes stressful environmental conditions, such as nitrogen limitation. In the beta-rhizobial strain Paraburkholderia phymatum STM815, the alternative sigma factor σ54 (or RpoN) has recently been shown to control nitrogenase activity during symbiosis with Phaseolus vulgaris. In this study, we determined P. phymatum’s σ54 regulon under nitrogen-limited free-living conditions. Among the genes significantly downregulated in the absence of σ54, we found a C4-dicarboxylate carrier protein (Bphy_0225), a flagellar biosynthesis cluster (Bphy_2926-64), and one of the two type VI secretion systems (T6SS-b) present in the P. phymatum STM815 genome (Bphy_5978-97). A defined σ54 mutant was unable to grow on C4 dicarboxylates as sole carbon source and was less motile compared to the wild-type strain. Both defects could be complemented by introducing rpoNin trans. Using promoter reporter gene fusions, we also confirmed that the expression of the T6SS-b cluster is regulated by σ54. Accordingly, we show that σ54 affects in vitro competitiveness of P. phymatum STM815 against Paraburkholderia diazotrophica.

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Section: Discussionmentioning

confidence: 99%

Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression

et al. 2020

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“…In this study, RNA-seq was employed to analyze the transcriptome-wide regulome of RpoN1 and RpoN2 and elucidate their co-regulatory and specific-regulatory pathways in Xoo . In previous reports, the regulatory roles of two homologous σ 54 factors were found to be no overlapping in Xanthomonas campestris ( Li et al, 2020 ). However, in Xoo , both RpoN1 and RpoN2 were involved in regulating flagellar assembly, chemotaxis and c-di-GMP synthesis, and degradation.…”

Section: Discussionmentioning

confidence: 92%

“…In R. solanacearum, rpoN1, but not rpoN2, is necessary for virulence, twitching motility, natural transformation, and growth on nitrate (Ray et al, 2015). However, in X. campestris, RpoN1 regulates branched-chain fatty acid production and diffusible signal synthesis, whereas RpoN2 regulates swimming motility, biofilms, EPS production, and virulence (Li et al, 2020). Unlike these studies, in the current study, both RpoN1 and RpoN2 were involved in regulating Xoo swimming motility and virulence (Figures 1, 2).…”

Section: Discussionmentioning

confidence: 99%

“…In Xanthomonas campestris , σ 54 factor RpoN2 regulates flagellar biosynthesis, swimming motility, biofilm formation, EPS, and virulence. In contrast, its homologous protein RpoN1 is involved in branched-chain fatty acid production and quorum sensing ( Li et al, 2020 ). These studies demonstrated specific regulatory roles and biological functions of σ 54 factors in pathogenic bacteria.…”

Section: Introductionmentioning

confidence: 99%

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Transcriptome Analysis Revealed Overlapping and Special Regulatory Roles of RpoN1 and RpoN2 in Motility, Virulence, and Growth of Xanthomonas oryzae pv. oryzae

Nguyen

Yang

et al. 2021

Front. Microbiol.

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σ54 factor (RpoN) plays a crucial role in bacterial motility, virulence, growth, and other biological functions. In our previous study, two homologous σ54 factors, RpoN1 and RpoN2, were identified in Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight in rice. However, their functional roles, i.e., whether they exert combined or independent effects, remain unknown. In the current study, rpoN1 or rpoN2 deletion in Xoo significantly disrupted bacterial swimming motility, flagellar assembly, and virulence. Transcriptome analysis led to the identification of 127 overlapping differentially expressed genes (DEGs) regulated by both RpoN1 and RpoN2. Furthermore, GO and KEGG classification demonstrated that these DEGs were highly enriched in flagellar assembly, chemotaxis, and c-di-GMP pathways. Interestingly, ropN1 deletion decreased ropN2 transcription, while rpoN2 deletion did not affect ropN1 transcription. No interaction between the rpoN2 promoter and RpoN1 was detected, suggesting that RpoN1 indirectly regulates rpoN2 transcription. In addition, RpoN1-regulated DEGs were specially enriched in ribosome, carbon, and nitrogen metabolism pathways. Besides, bacterial growth was remarkably repressed in ΔrpoN1 but not in ΔrpoN2. Taken together, this study demonstrates the overlapping and unique regulatory roles of RpoN1 and RpoN2 in motility, virulence, growth and provides new insights into the regulatory mechanism of σ54 factors in Xoo.

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“…The protein purity was monitored by SDS-PAGE. His 6 -tagged protein expression and puri cation were performed as described previously [35][36][37] .…”

Section: Protein Expression and Puri Cationmentioning

confidence: 99%

A predatory soil bacterium reprograms a quorum sensing signal system to regulate antifungal weapon production in a cyclic-di-GMP-independent manner

Wang

et al. 2021

Preprint

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Soil bacteria often provide multiple weapons for eukaryotes or prokaryotes to use against predators. Diffusible signal factors (DSFs) represent a unique group of quorum sensing (QS) chemicals that modulate interspecies competition in bacteria that do not produce antibiotic-like molecules. However, the molecular mechanism by which DSF-mediated QS systems regulate weapons production for interspecies competition remains largely unknown in soil biocontrol bacteria. In this study, we found that the necessary QS system component protein RpfG from Lysobacter, in addition to being a cyclic dimeric GMP (c-di-GMP) phosphodiesterase (PDE), regulates the biosynthesis of an antifungal weapon (heat-stable antifungal factor, HSAF), which does not appear to depend on the enzymatic activity. Interestingly, we showed for the first time that RpfG interacts with three hybrid two-component system (HyTCS) proteins, HtsH1, HtsH2, and HtsH3, to regulate HSAF production in Lysobacter. In vitro studies showed that each of these proteins interacted with RpfG, which reduced the PDE activity of RpfG. Finally, we showed that the cytoplasmic proportions of these proteins depended on their phosphorylation activity and binding to the promoter controlling the genes implicated in HSAF synthesis. These findings reveal a new mechanism of DSF signalling in antifungal weapon production in soil bacteria.

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

Cited by 21 publications

References 64 publications

Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression

Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression

Transcriptome Analysis Revealed Overlapping and Special Regulatory Roles of RpoN1 and RpoN2 in Motility, Virulence, and Growth of Xanthomonas oryzae pv. oryzae

A predatory soil bacterium reprograms a quorum sensing signal system to regulate antifungal weapon production in a cyclic-di-GMP-independent manner

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