Involvement of tonB-exbBD1D2 operon in infection of Xanthomonas campestris phage phi L7.
phi L7 is a lytic bacteriophage infecting Xanthomonas campestris pv. campestris, a Gram-negative bacterium producing xanthan gum and causing black rot in crucifers. A mutant resistant to phi L7 was isolated by Tn5 mutagenesis. Sequence analysis indicated that the gene responsible for the mutation is tonB encoding an inner membrane protein previously shown to be required for iron uptake and pathogenesis. This gene is clustered with three other genes, tonB-exbB-exbD1-exbD2. Results of insertional mutations, DNA and protein sequence analyses, phage sensitivity tests, transfection tests, complementation tests, and phage adsorption assays together with the cellular location of the proteins indicate that TonB, ExbB, and ExbD1 are essential for penetration of phage phi L7. The genome organization, structural features of the tonB-exb region, and transcriptional analyses including Northern hybridization, reporter assays, and primer extension together indicate that the four genes are organized into an operon.
Hung
Chih-Hsin
CH
Department of Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan.
Yang
Chi-Fan
CF
Yang
Chiou-Ying
CY
Tseng
Yi-Hsiung
YH
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001435:Bacteriophages / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D017930:Genes, Reporter; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009876:Operon; D010935:Plant Diseases / Q000382:microbiology; D011401:Promoter Regions, Genetic; D016959:Xanthomonas campestris / Q000235:genetics* / Q000821:virology
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; C057616:tonB protein, Bacteria