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Crp ‐dependent cytochrome bd oxidase confers nitrite resistance to S hewanella oneidensis
Author(s) -
Fu Huihui,
Chen Haijiang,
Wang Jixuan,
Zhou Guangqi,
Zhang Haiyan,
Zhang Lili,
Gao Haichun
Publication year - 2013
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12091
Subject(s) - shewanella oneidensis , nitrite , biology , operon , nitrite reductase , biochemistry , transposon mutagenesis , nitrate , oxidase test , mutant , cytochrome , microbiology and biotechnology , bacteria , transposable element , gene , enzyme , genetics , ecology
Summary S hewanella oneidensis is able to respire on a variety of organic and inorganic substrates, including nitrate and nitrite. Conversion of nitrate to nitrite and nitrite to ammonium is catalysed by periplasmic nitrate and nitrite reductases ( NAP and NRF ) respectively. Global regulator Crp ( c yclic AMP r eceptor p rotein) is essential for growth of S . oneidensis on both nitrate and nitrite. In this study, we discovered that crp mutants are not only severely deficient in nitrate or nitrite respiration, but are also hypersensitive to nitrite. This hypersusceptibility phenotype is independent of nitrite respiration. Using random transposon mutagenesis, we obtained 73 Δ crp suppressor strains resistant to nitrite. Transposon insertion sites in 24 suppressor strains were exclusively mapped in the region upstream of the cyd operon encoding a cytochrome bd oxidase, resulting in expression of the operon now driven by a Crp ‐independent promoter. Further investigation indicated that the promoter in suppressor strains comes from the transposon. Mutational analysis of the cydB gene (encoding the essential subunit II of the bd oxidase) confirmed that the cytochrome bd oxidase confers nitrite resistance to S . oneidensis .