Publication: Regulation of the cobalt/nickel efflux operon DmeRF in Agrobacterium tumefaciens and a link between the iron-sensing regulator rirA and cobalt/nickel resistance
Issued Date
2016-01-01
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ISSN
10985336
00992240
00992240
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2-s2.0-84979944301
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Mahidol University
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SCOPUS
Bibliographic Citation
Applied and Environmental Microbiology. Vol.82, No.15 (2016), 4732-4742
Suggested Citation
Thanittra Dokpikul, Paweena Chaoprasid, Kritsakorn Saninjuk, Sirin Sirirakphaisarn, Jaruwan Johnrod, Sumontha Nookabkaew, Rojana Sukchawalit, Skorn Mongkolsuk Regulation of the cobalt/nickel efflux operon DmeRF in Agrobacterium tumefaciens and a link between the iron-sensing regulator rirA and cobalt/nickel resistance. Applied and Environmental Microbiology. Vol.82, No.15 (2016), 4732-4742. doi:10.1128/AEM.01262-16 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/42793
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Title
Regulation of the cobalt/nickel efflux operon DmeRF in Agrobacterium tumefaciens and a link between the iron-sensing regulator rirA and cobalt/nickel resistance
Abstract
© 2016, American Society for Microbiology. The Agrobacterium tumefaciens C58 genome harbors an operon containing the dmeR (Atu0890) and dmeF (Atu0891) genes, which encode a transcriptional regulatory protein belonging to the RcnR/CsoR family and a metal efflux protein belonging to the cation diffusion facilitator (CDF) family, respectively. The dmeRF operon is specifically induced by cobalt and nickel, with cobalt being the more potent inducer. Promoter-lacZ transcriptional fusion, an electrophoretic mobility shift assay, and DNase I footprinting assays revealed that DmeR represses dmeRF transcription through direct binding to the promoter region upstream of dmeR. A strain lacking dmeF showed increased accumulation of intracellular cobalt and nickel and exhibited hypersensitivity to these metals; however, this strain displayed full virulence, comparable to that of the wild-type strain, when infecting a Nicotiana benthamiana plant model under the tested conditions. Cobalt, but not nickel, increased the expression of many iron-responsive genes and reduced the induction of the SoxR-regulated gene sodBII. Furthermore, control of iron homeostasis via RirA is important for the ability of A. tumefaciens to cope with cobalt and nickel toxicity.