Contribution of Surfactin and SwrA to Flagellin Expression, Swimming, and Surface Motility in Bacillus subtilis

Ghelardi, Emilia; Salvetti, Sara; Ceragioli, Mara; Gueye, Sokhna Aissatou; Celandroni, Francesco; Senesi, Sonia

doi:10.1128/aem.01341-12

Cited by 57 publications

(45 citation statements)

References 36 publications

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“…In addition, strong biosurfactant nature of surfactin plays an intricate role on bacterial swarming to nutrient rich environments and to the biofilm expansion (Kinsinger et al ., ; Bais et al ., ; Angelini et al ., ). In accordance with previous research (Ghelardi et al ., ) our results also indicated that the surfactins influenced swarming motility and were able to enhance the phenotype of swarming motility in surfactin‐deficient Bacillus spp mutants, particularly in B. atrophaeus . We could not observe any surfactin A or C specific effect, pointing to an effect due to the amphiphilic nature of the surfactins or variant unspecific signaling.…”

Section: Discussionmentioning

confidence: 99%

Surfactin variants mediate species‐specific biofilm formation and root colonization in Bacillus

Aleti

Lehner

Bacher

et al. 2016

Environmental Microbiology

101

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Cyclic lipopeptides (cLP) and especially surfactins produced by Bacillus spp. trigger biofilm formation and root colonization and are crucial for biocontrol activity and systemic resistance in plants. Bacillus atrophaeus 176s isolated from the moss Tortella tortuosa produces the cLP fengycins, iturins and surfactins, possesses antifungal activities and can protect tomato, lettuce and sugar beet against Rhizoctonia solani infection. In B. atrophaeus we identified for the first time the variant surfactin C, which differs from surfactin A produced by B. subtilis and B. amyloliquefaciens by an isoleucine instead of a leucine at position 7 of the lipopeptide backbone. The analysis of the complete surfactin gene clusters revealed that the dissimilarity is encoded in the adenylation domain of srfC and show that surfactin variations are distributed in a species-specific manner in bacilli. We demonstrate that the surfactin A and C with subtle structural differences have varying signal strengths on biofilm formation and root colonization and act specifically on the respective producing strain. This became evident as biofilm formation and root colonization but not swarming motility in surfactin biosynthesis mutants was restored differentially in the presence of exogenously supplemented cognate and non-cognate surfactin variants.

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Section: Discussionmentioning

confidence: 99%

Surfactin variants mediate species‐specific biofilm formation and root colonization in Bacillus

Aleti

Lehner

Bacher

et al. 2016

Environmental Microbiology

101

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“…(We sound a cautionary note in this regard when assuming that surfactants extract liquid from the substrate [58,59].) In B. subtilis, the complete lack of motility in the absence of surfactin could stem from an additional signaling function for surfactin, which includes the production of more flagella, as judged by poor flagellation of surfactantdeficient mutants (60) (22,57,62,63).…”

Section: Bacterial Mechanisms For Enabling Surface Navigationmentioning

confidence: 99%

Swarming: Flexible Roaming Plans

Partridge

Harshey

2012

Journal of Bacteriology

165

216

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Movement over an agar surface via swarming motility is subject to formidable challenges not encountered during swimming. Bacteria display a great deal of flexibility in coping with these challenges, which include attracting water to the surface, overcoming frictional forces, and reducing surface tension. Bacteria that swarm on "hard" agar surfaces (robust swarmers) display a hyperflagellated and hyperelongated morphology. Bacteria requiring a "softer" agar surface (temperate swarmers) do not exhibit such a dramatic morphology. For polarly flagellated robust swarmers, there is good evidence that restriction of flagellar rotation somehow signals the induction of a large number of lateral flagella, but this scenario is apparently not relevant to temperate swarmers. Swarming bacteria can be further subdivided by their requirement for multiple stators (Mot proteins) or a statorassociated protein (FliL), secretion of essential polysaccharides, cell density-dependent gene regulation including surfactant synthesis, a functional chemotaxis signaling pathway, appropriate cyclic (c)-di-GMP levels, induction of virulence determinants, and various nutritional requirements such as iron limitation or nitrate availability. Swarming strategies are as diverse as the bacteria that utilize them. The strength of these numerous designs stems from the vantage point they offer for understanding mechanisms for effective colonization of surface niches, acquisition of pathogenic potential, and identification of environmental signals that regulate swarming. The signature swirling and streaming motion within a swarm is an interesting phenomenon in and of itself, an emergent behavior with properties similar to flocking behavior in diverse systems, including birds and fish, providing a convenient new avenue for modeling such behavior.

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“…This is good evidence that surfactin shares same substrates with γ‐PGA. Besides, as mentioned above, surfactin upregulates the transcription of the flagellin gene (Ghelardi et al., ). Chan, Guttenplan, and Kearns () found that defects in the flagellar motor increase synthesis of poly‐γ‐Glutamate in B .…”

Section: Discussionmentioning

confidence: 91%

Mutations in genes encoding antibiotic substances increase the synthesis of poly-γ-glutamic acid inBacillus amyloliquefaciensLL3

et al. 2016

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Poly‐γ‐glutamic acid (γ‐PGA) is an important natural biopolymer that is used widely in fields of foods, medicine, cosmetics, and agriculture. Several B. amyloliquefaciens LL3 mutants were constructed to improve γ‐PGA synthesis via single or multiple marker‐less in‐frame deletions of four gene clusters (itu, bae, srf, and fen) encoding antibiotic substances. γ‐PGA synthesis by the Δsrf mutant showed a slight increase (4.1 g/L) compared with that of the wild‐type strain (3.3 g/L). The ΔituΔsrf mutant showed increased γ‐PGA yield from 3.3 to 4.5 g/L, with an increase of 36.4%. The γ‐PGA yield of the ΔituΔsrfΔfen and ΔituΔsrfΔfenΔbae mutants did not show a further increase. The four gene clusters’ roles in swarming motility and biofilm formation were also studied. The Δsrf and Δbae mutant strains were both significantly defective in swarming, indicating that bacillaene and surfactin are involved in swarming motility of B. amyloliquefaciens LL3. Furthermore, Δsrf and Δitu mutant strains were obviously defective in biofilm formation; therefore, iturin and surfactin must play important roles in biofilm formation in B. amyloliquefaciens LL3.

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Contribution of Surfactin and SwrA to Flagellin Expression, Swimming, and Surface Motility in Bacillus subtilis

Cited by 57 publications

References 36 publications

Surfactin variants mediate species‐specific biofilm formation and root colonization in Bacillus

Surfactin variants mediate species‐specific biofilm formation and root colonization in Bacillus

Swarming: Flexible Roaming Plans

Mutations in genes encoding antibiotic substances increase the synthesis of poly-γ-glutamic acid inBacillus amyloliquefaciensLL3

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