Analysis of the lateral flagellar gene system of Aeromonas hydrophila AH-3.
Mesophilic Aeromonas strains express a polar flagellum in all culture conditions, and certain strains produce lateral flagella on semisolid media or on surfaces. Although Aeromonas lateral flagella have been described as a colonization factor, little is known about their organization and expression. Here we characterized the complete lateral flagellar gene cluster of Aeromonas hydrophila AH-3 containing 38 genes, 9 of which (lafA-U) have been reported previously. Among the flgLL and lafA structural genes we found a modification accessory factor gene (maf-5) that is involved in formation of lateral flagella; this is the first time that such a gene has been described for lateral flagellar gene systems. All Aeromonas lateral flagellar genes were located in a unique chromosomal region, in contrast to Vibrio parahaemolyticus, in which the analogous genes are distributed in two different chromosomal regions. In A. hydrophila mutations in flhAL, lafK, fliJL, flgNL, flgEL, and maf-5 resulted in a loss of lateral flagella and reductions in adherence and biofilm formation, but they did not affect polar flagellum synthesis. Furthermore, we also cloned and sequenced the A. hydrophila AH-3 alternative sigma factor sigma54 (rpoN); mutation of this factor suggested that it is involved in expression of both types of flagella.
Canals
Rocío
R
Departamento Microbiología, Facultad Biología, Universidad Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Altarriba
Maria
M
Vilches
Silvia
S
Horsburgh
Gavin
G
Shaw
Jonathan G
JG
Tomás
Juan M
JM
Merino
Susana
S
D016980:Aeromonas hydrophila / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure*; D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D002460:Cell Line; D004269:DNA, Bacterial; D004847:Epithelial Cells / Q000382:microbiology; D005407:Flagella; D005408:Flagellin / Q000235:genetics*; D008969:Molecular Sequence Data
D004269:DNA, Bacterial; D005408:Flagellin