Characterization of two TonB systems in marine fish pathogen Vibrio alginolyticus: their roles in iron utilization and virulence.
In Gram-negative bacteria, the TonB/ExbB/ExbD complex is required to energize the specific high-affinity receptors mediating iron uptake processes. In fish pathogen Vibrio alginolyticus MVP01, which exhibited capacities to scavenge iron sources with various specific iron uptake systems, we identified and characterized two sets of TonB systems. In V. alginolyticus, TonB1 and TonB2 systems were arrayed as TonB1-ExbB1-ExbD1 and ExbB2-ExbD2-TonB2, respectively. The transcription of the TonB systems was regulated by the iron concentration in culture medium. While TonB1 system specifically contributed to the hemin and hemoglobin utilization in V. alginolyticus MVP01, both of the TonB systems showed abilities to support the utilization of iron sources from ferrichrome and vibrioferrin, the endogenous siderophore of V. alginolyticus. In addition, when mutants of the TonB systems were inoculated intraperitoneally into the fish Brachydanio rerio, marked attenuation in virulence of V. alginolyticus was observed, indicating that both of the TonB systems are essential for the virulence of V. alginolyticus.
Wang
Qiyao
Q
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
Liu
Qin
Q
Cao
Xiaodan
X
Yang
Minjun
M
Zhang
Yuanxing
Y
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D002951:Citrates / Q000378:metabolism; D005291:Ferrichrome / Q000378:metabolism; D005393:Fish Diseases / Q000382:microbiology; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D006427:Hemin / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology*; D008969:Molecular Sequence Data; D011760:Pyrrolidinones / Q000378:metabolism; D016415:Sequence Alignment; D014735:Vibrio Infections / Q000382:microbiology / Q000662:veterinary; D044149:Vibrio alginolyticus / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics* / Q000502:physiology*; D015027:Zebrafish
D001426:Bacterial Proteins; D002951:Citrates; D006454:Hemoglobins; D008565:Membrane Proteins; D011760:Pyrrolidinones; D037521:Virulence Factors; C057616:tonB protein, Bacteria; D005291:Ferrichrome; C090126:vibrioferrin; D006427:Hemin; D007501:Iron