title: Enhancement of geraniol resistance of Escherichia coli by MarA overexpression.
abstract: Improvement of a microorganism's tolerance against organic solvents is required for a microbial factory producing terpenoid based biofuels. The bacterial genes, marA, imp, cls and cti have been found to increase organic solvent tolerance. Thus, the tolerance against the following terpenoids (isopentenol, geraniol, myrcene, and farnesol) was studied with overexpression of marA, imp, cls and cti genes in Escherichia coli. The marA overexpression significantly enhanced the tolerance of E. coli against geraniol, whereas there was no tolerance improvement against the terpenoids by overexpression of cls and cti genes. The imp overexpression even yielded sensitive phenotype to the tested solvents. The colony forming efficiency of the marA overexpressing E. coli was increased by 10(4)-fold in plate overlay of geraniol compared to that of wild type E. coli and a two-fold decrease of intracellular geraniol accumulation was also observed in liquid culture of geraniol. Single knock-out mutations of marA, or one of the following genes (acrA, acrB and tolC) encoding AcrAB-TolC efflux pump made E. coli hypersensitive to geraniol. The geraniol tolerance conferred by marA overexpression was attributed to the AcrAB-TolC efflux pump that is activated by MarA.
authors.affiliation: Division of Applied Life Science (Brain Korea 21 Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, 900 Gajwadong, Jinju, Republic of Korea.
authors.forename: Asad Ali
authors.initials: AA
authors.lastname: Shah
authors.forename: Chonglong
authors.initials: C
authors.lastname: Wang
authors.forename: Young-Ryun
authors.initials: YR
authors.lastname: Chung
authors.forename: Jae-Yean
authors.initials: JY
authors.lastname: Kim
authors.forename: Eui-Sung
authors.initials: ES
authors.lastname: Choi
authors.forename: Seon-Won
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000080462:Acyclic Monoterpenes; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D008074:Lipoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D009154:Mutation; D012997:Solvents / Q000633:toxicity*; D013729:Terpenes / Q000378:metabolism / Q000633:toxicity*
chemical_list: D000080462:Acyclic Monoterpenes; D001425:Bacterial Outer Membrane Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012997:Solvents; D013729:Terpenes; C083497:AcrA protein, E coli; C083496:AcrB protein, E coli; C475958:LptD protein, E coli; C080002:MarA protein, E coli; C073126:tolC protein, E coli; C007836:geraniol