title: Type IV pilin is glycosylated in Pseudomonas syringae pv. tabaci 6605 and is required for surface motility and virulence.
abstract: Type IV pilin (PilA) is a major constituent of pilus and is required for bacterial biofilm formation, surface motility and virulence. It is known that mature PilA is produced by cleavage of the short leader sequence of the pilin precursor, followed by methylation of N-terminal phenylalanine. The molecular mass of the PilA mature protein from the tobacco bacterial pathogen Pseudomonas syringae pv. tabaci 6605 (Pta 6605) has been predicted to be 12 329 Da from its deduced amino acid sequence. Previously, we have detected PilA as an approximately 13-kDa protein by immunoblot analysis with anti-PilA-specific antibody. In addition, we found the putative oligosaccharide-transferase gene tfpO downstream of pilA. These findings suggest that PilA in Pta 6605 is glycosylated. The defective mutant of tfpO (ΔtfpO) shows reductions in pilin molecular mass, surface motility and virulence towards host tobacco plants. Thus, pilin glycan plays important roles in bacterial motility and virulence. The genetic region around pilA was compared among P. syringae pathovars. The tfpO gene exists in some strains of pathovars tabaci, syringae, lachrymans, mori, actinidiae, maculicola and P. savastanoi pv. savastanoi. However, some strains of pathovars tabaci, syringae, glycinea, tomato, aesculi and oryzae do not possess tfpO, and the existence of tfpO is independent of the classification of pathovars/strains in P. syringae. Interestingly, the PilA amino acid sequences in tfpO-possessing strains show higher homology with each other than with tfpO-nonpossessing strains. These results suggest that tfpO and pilA might co-evolve in certain specific bacterial strains.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Linh Chi
authors.initials: LC
authors.lastname: Nguyen
authors.forename: Fumiko
authors.initials: F
authors.lastname: Taguchi
authors.forename: Quang Minh
authors.initials: QM
authors.lastname: Tran
authors.forename: Kana
authors.initials: K
authors.lastname: Naito
authors.forename: Masanobu
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ohnishi-Kameyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ono
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yoshida
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiku
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishii
authors.forename: Yoshishige
authors.initials: Y
authors.lastname: Inagaki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Toyoda
authors.forename: Tomonori
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ichinose
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005408:Flagellin / Q000378:metabolism; D005798:Genes, Bacterial / Q000235:genetics; D006031:Glycosylation; D008969:Molecular Sequence Data; D009068:Movement; D009154:Mutation / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology*; D014026:Nicotiana / Q000821:virology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D005408:Flagellin; D036781:Fimbriae Proteins