Biofilm formation by Paracoccus denitrificans requires a type I secretion system-dependent adhesin BapA.
Paracoccus denitrificans is a non-swimming Gram-negative bacterium, with versatile respiration capability which has remarkable potentials for bioremediation, especially in water treatment. Although biofilms are important in water treatment systems, the genetic mechanisms underlying the cellular adherence and biofilm formation of this bacterium remain unknown. We show that P. denitrificans forms a thin biofilm on surfaces at the air-liquid interface under static conditions. The initial step of biofilm formation requires a biofilm-associated protein BapA, which we identified by transposon mutant screening. BapA contains a unique sequence of dipeptide repeats of aspartate and alanine. Our data indicate that BapA is translocated to the extracellular milieu by a type 1 secretion system, where it enables the cells to attach to the substratum. Furthermore, superresolution microscopy shows that BapA is localized on the cell surface, which alters the cell surface hydrophobicity. Our results show a crucial role of BapA that promotes the adhesion and biofilm formation of P. denitrificans.
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Keitaro
K
Yoshida
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.|Department of Plant and Microbial Biology, University of Zurich, Zürich 8008, Switzerland.
Masanori
M
Toyofuku
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Nozomu
N
Obana
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Nobuhiko
N
Nomura
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D057927:Hydrophobic and Hydrophilic Interactions; D010231:Paracoccus denitrificans / Q000378:metabolism / Q000502:physiology*; D000069177:Type I Secretion Systems / Q000378:metabolism*
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D000069177:Type I Secretion Systems
Paracoccus denitrificans; adhesin; bap; biofilm; motility; type I secretion system