title: Manganese scavenging and oxidative stress response mediated by type VI secretion system inBurkholderia thailandensis.
abstract: Type VI secretion system (T6SS) is a versatile protein export machinery widely distributed in Gram-negative bacteria. Known to translocate protein substrates to eukaryotic and prokaryotic target cells to cause cellular damage, the T6SS has been primarily recognized as a contact-dependent bacterial weapon for microbe-host and microbial interspecies competition. Here we report contact-independent functions of the T6SS for metal acquisition, bacteria competition, and resistance to oxidative stress. We demonstrate that the T6SS-4 inBurkholderia thailandensisis critical for survival under oxidative stress and is regulated by OxyR, a conserved oxidative stress regulator. The T6SS-4 is important for intracellular accumulation of manganese (Mn2+) under oxidative stress. Next, we identified a T6SS-4-dependent Mn2+-binding effector TseM, and its interacting partner MnoT, a Mn2+-specific TonB-dependent outer membrane transporter. Similar to the T6SS-4 genes, expression ofmnoTis regulated by OxyR and is induced under oxidative stress and low Mn2+conditions. Both TseM and MnoT are required for efficient uptake of Mn2+across the outer membrane under Mn2+-limited and -oxidative stress conditions. The TseM-MnoT-mediated active Mn2+transport system is also involved in contact-independent bacteria-bacteria competition and bacterial virulence. This finding provides a perspective for understanding the mechanisms of metal ion uptake and the roles of T6SS in bacteria-bacteria competition.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.|College of Life Sciences, Qufu Normal University, Qufu, Shandong 273165, China.
authors.forename: Meiru
authors.initials: M
authors.lastname: Si
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4Z6.
authors.forename: Brianne
authors.initials: B
authors.lastname: Burkinshaw
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4Z6 xihuishen@nwsuaf.edu.cn tdong@ucalgary.ca.
authors.forename: Tao G
authors.initials: TG
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China; xihuishen@nwsuaf.edu.cn tdong@ucalgary.ca.
authors.forename: Xihui
authors.initials: X
authors.lastname: Shen
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001665:Binding Sites; D001692:Biological Transport; D019117:Burkholderia / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D019121:Burkholderia Infections / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D007814:Larva / Q000382:microbiology; D008345:Manganese / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D008958:Models, Molecular; D009036:Moths / Q000382:microbiology; D009154:Mutation; D009876:Operon; D018384:Oxidative Stress / Q000235:genetics; D010802:Phylogeny; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000378:metabolism; D020218:Response Elements; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity; D000069376:Type VI Secretion Systems / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins; D026901:Membrane Transport Proteins; D012097:Repressor Proteins; D000069376:Type VI Secretion Systems; D008345:Manganese
keywords: Burkholderia; ion uptake; outer membrane transporter; oxidative stress; type VI secretion