title: Production of indole-3-acetic acid in the plant-beneficial strain Pseudomonas chlororaphis O6 is negatively regulated by the global sensor kinase GacS.
abstract: Certain plant growth-promoting bacteria, such as Pseudomonas fluorescens 89B61 and Bacillus pumilus SE34, secreted high levels of indole-3-acetic acid (IAA) in tryptophan-amended medium in stationary phase as determined by chromogenic analysis and high-performance liquid chromatography. Two other growth-promoting strains, P. chlororaphis O6 and Serratia marcescens 90-166, did not produce these high levels of IAA. However, when the gacS mutant of P. chlororaphis O6 was grown in tryptophan-supplemented medium, IAA was detected in culture filtrates. IAA production by the gacS mutant in P. chlororaphis O6 was repressed in the tryptophan medium by complementation with the wild-type gacS gene. Thus, the global regulatory Gac system in P. chlororaphis O6 acts as a negative regulator of IAA production from trypophan.
authors.affiliation: Agricultural Plant Stress Research Center and Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea,
authors.forename: Beom Ryong
authors.initials: BR
authors.lastname: Kang
authors.forename: Kwang Yeol
authors.initials: KY
authors.lastname: Yang
authors.forename: Baik Ho
authors.initials: BH
authors.lastname: Cho
authors.forename: Tae Ho
authors.initials: TH
authors.lastname: Han
authors.forename: In Seon
authors.initials: IS
authors.lastname: Kim
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Lee
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Anderson
authors.forename: Young Cheol
authors.initials: YC
authors.lastname: Kim
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D003470:Culture Media / Q000737:chemistry; D007210:Indoleacetic Acids / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology*; D011549:Pseudomonas / Q000378:metabolism*; D014026:Nicotiana / Q000254:growth & development; D014157:Transcription Factors / Q000235:genetics*; D014364:Tryptophan / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D007210:Indoleacetic Acids; D014157:Transcription Factors; C030737:indoleacetic acid; D014364:Tryptophan; C074165:lemA protein, bacterial