Rhizobium tropici response to acidity involves activation of glutathione synthesis.
Rhizobium tropici CIAT899 displays intrinsic tolerance to acidity, and efficiently nodulates Phaseolus vulgaris at low pH. By characterizing a gshB mutant strain, glutathione has been previously demonstrated to be essential for R. tropici tolerance to acid stress. The wild-type gshB gene region has been cloned and its transcription profile has been characterized by using quantitative real-time PCR and transcriptional gene fusions. Activation of the gshB gene under acid-stress conditions was demonstrated. gshB is also induced by UV irradiation. Upstream from gshB a putative sigma(70) promoter element and an inverted repeat sequence were identified, which are proposed to be involved in expression under neutral and acidic conditions, respectively. Gel retardation assays indicate that transcription in acid conditions may involve protein binding to an upstream regulatory region.
Muglia
Cecilia I
CI
Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900, La Plata, Argentina.
Grasso
Daniel H
DH
Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900, La Plata, Argentina.
Aguilar
O Mario
OM
Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900, La Plata, Argentina.
D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005978:Glutathione / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D027805:Phaseolus / Q000382:microbiology; D011401:Promoter Regions, Genetic; D042162:Rhizobium tropici / Q000378:metabolism*; D012988:Soil Microbiology
D001426:Bacterial Proteins; D005978:Glutathione