Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395
ABSTRACT Flagellar motility is crucial for the swim-and-stick lifestyle and plays an important role in bacterial-algal interactions of Rhodobacterales. This alphaproteobacterial order contains three distinct types of flagellar gene clusters (FGCs) for the formation of a functional flagellum. Our phy...
Saved in:
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2025-08-01
|
| Series: | mSystems |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/msystems.00419-25 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849329414871973888 |
|---|---|
| author | Jürgen Tomasch Pascal Bartling John Vollmers Lars Wöhlbrand Michael Jarek Manfred Rohde Henner Brinkmann Heike M. Freese Ralf Rabus Jörn Petersen |
| author_facet | Jürgen Tomasch Pascal Bartling John Vollmers Lars Wöhlbrand Michael Jarek Manfred Rohde Henner Brinkmann Heike M. Freese Ralf Rabus Jörn Petersen |
| author_sort | Jürgen Tomasch |
| collection | DOAJ |
| description | ABSTRACT Flagellar motility is crucial for the swim-and-stick lifestyle and plays an important role in bacterial-algal interactions of Rhodobacterales. This alphaproteobacterial order contains three distinct types of flagellar gene clusters (FGCs) for the formation of a functional flagellum. Our phylogenetically broad taxon sampling of more than 300 genomes revealed that the most common FGC, the fla1-type, was probably already present in the common ancestor of Rhodobacterales and was strictly vertically inherited, while the other two FGC types, fla2 and fla3, were spread via horizontal operon transfers. Swimming of the marine model organism Phaeobacter inhibens DSM 17395 (Roseobacteraceae) is mediated by the archetypal fla1-type flagellum. Screening of 13,000 transposon mutants of P. inhibens on soft agar plates revealed that 40 genes, including four genes encoding conserved but not yet characterized proteins (CP1–4) within the FGC, are essential for motility. Exoproteome analyses indicated that CP1–4 are required at different stages of flagellar assembly. Only eight genes outside the FGC were identified as essential for swimming motility, including all three genes of the CtrA phosphorelay. Using comparative transcriptomics of ΔcckA, ΔchpT, and ΔctrA mutants of the distantly related model organisms P. inhibens and Dinoroseobacter shibae DSM 16493, we identified genes for the flagellum and cyclic di-GMP turnover as core targets of the CtrA phosphorelay and a conserved connection with quorum sensing across members of the Rhodobacterales.IMPORTANCEThe bacterial flagellum is a sophisticated nanomachine for swimming motility and rapid chemotactic response to gradients of attractants or repellents in the environment. It is structurally highly conserved and has been intensively studied in gammaproteobacterial model bacteria such as Escherichia coli and Salmonella enterica. However, the flagellar gene clusters of different alphaproteobacterial orders have distinct structures and compositions, as demonstrated by the three flagellar systems of Rhodobacterales investigated in the current study. The archetypal fla1-type flagellum originated in its common ancestor and evolved synchronously with the host. The universal presence of four as yet uncharacterized essential genes in fla1-type FGCs (CP1–4) reflects the order-specific adaptation of the flagellar system during bacterial evolution. Comparative transcriptome analyses of ΔcckA, ΔchpT, and ΔctrA mutants showed that the core function of the CtrA phosphorelay in Rhodobacterales is the transcriptional control of flagellar genes. |
| format | Article |
| id | doaj-art-9fe27bcb7f774b4899c5ea154d61c41f |
| institution | Kabale University |
| issn | 2379-5077 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mSystems |
| spelling | doaj-art-9fe27bcb7f774b4899c5ea154d61c41f2025-08-20T03:47:16ZengAmerican Society for MicrobiologymSystems2379-50772025-08-0110810.1128/msystems.00419-25Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395Jürgen Tomasch0Pascal Bartling1John Vollmers2Lars Wöhlbrand3Michael Jarek4Manfred Rohde5Henner Brinkmann6Heike M. Freese7Ralf Rabus8Jörn Petersen9Laboratory of Anoxygenic Phototrophs, Institute of Microbiology of the Czech Academy of Science – Centre Algatech, Třeboň, Czech RepublicLeibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Lower Saxony, GermanyInstitute for Biological Interfaces 5, Karlsruhe Institute of Technology, Karlsruhe, Baden-Württemberg, GermanyGeneral and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Lower Saxony, GermanyGenome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Lower Saxony, GermanyGenome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Lower Saxony, GermanyLeibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Lower Saxony, GermanyLeibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Lower Saxony, GermanyGeneral and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Lower Saxony, GermanyLeibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Lower Saxony, GermanyABSTRACT Flagellar motility is crucial for the swim-and-stick lifestyle and plays an important role in bacterial-algal interactions of Rhodobacterales. This alphaproteobacterial order contains three distinct types of flagellar gene clusters (FGCs) for the formation of a functional flagellum. Our phylogenetically broad taxon sampling of more than 300 genomes revealed that the most common FGC, the fla1-type, was probably already present in the common ancestor of Rhodobacterales and was strictly vertically inherited, while the other two FGC types, fla2 and fla3, were spread via horizontal operon transfers. Swimming of the marine model organism Phaeobacter inhibens DSM 17395 (Roseobacteraceae) is mediated by the archetypal fla1-type flagellum. Screening of 13,000 transposon mutants of P. inhibens on soft agar plates revealed that 40 genes, including four genes encoding conserved but not yet characterized proteins (CP1–4) within the FGC, are essential for motility. Exoproteome analyses indicated that CP1–4 are required at different stages of flagellar assembly. Only eight genes outside the FGC were identified as essential for swimming motility, including all three genes of the CtrA phosphorelay. Using comparative transcriptomics of ΔcckA, ΔchpT, and ΔctrA mutants of the distantly related model organisms P. inhibens and Dinoroseobacter shibae DSM 16493, we identified genes for the flagellum and cyclic di-GMP turnover as core targets of the CtrA phosphorelay and a conserved connection with quorum sensing across members of the Rhodobacterales.IMPORTANCEThe bacterial flagellum is a sophisticated nanomachine for swimming motility and rapid chemotactic response to gradients of attractants or repellents in the environment. It is structurally highly conserved and has been intensively studied in gammaproteobacterial model bacteria such as Escherichia coli and Salmonella enterica. However, the flagellar gene clusters of different alphaproteobacterial orders have distinct structures and compositions, as demonstrated by the three flagellar systems of Rhodobacterales investigated in the current study. The archetypal fla1-type flagellum originated in its common ancestor and evolved synchronously with the host. The universal presence of four as yet uncharacterized essential genes in fla1-type FGCs (CP1–4) reflects the order-specific adaptation of the flagellar system during bacterial evolution. Comparative transcriptome analyses of ΔcckA, ΔchpT, and ΔctrA mutants showed that the core function of the CtrA phosphorelay in Rhodobacterales is the transcriptional control of flagellar genes.https://journals.asm.org/doi/10.1128/msystems.00419-25flagellar motilityflagellar gene regulationCtrA phosphorelayRhodobacteralesevolution |
| spellingShingle | Jürgen Tomasch Pascal Bartling John Vollmers Lars Wöhlbrand Michael Jarek Manfred Rohde Henner Brinkmann Heike M. Freese Ralf Rabus Jörn Petersen Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395 mSystems flagellar motility flagellar gene regulation CtrA phosphorelay Rhodobacterales evolution |
| title | Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395 |
| title_full | Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395 |
| title_fullStr | Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395 |
| title_full_unstemmed | Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395 |
| title_short | Structural and regulatory determinants of flagellar motility in Rhodobacterales—the archetypal flagellum of Phaeobacter inhibens DSM 17395 |
| title_sort | structural and regulatory determinants of flagellar motility in rhodobacterales the archetypal flagellum of phaeobacter inhibens dsm 17395 |
| topic | flagellar motility flagellar gene regulation CtrA phosphorelay Rhodobacterales evolution |
| url | https://journals.asm.org/doi/10.1128/msystems.00419-25 |
| work_keys_str_mv | AT jurgentomasch structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT pascalbartling structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT johnvollmers structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT larswohlbrand structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT michaeljarek structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT manfredrohde structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT hennerbrinkmann structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT heikemfreese structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT ralfrabus structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 AT jornpetersen structuralandregulatorydeterminantsofflagellarmotilityinrhodobacteralesthearchetypalflagellumofphaeobacterinhibensdsm17395 |