Rhizobium tropici response to acidity involves activation of glutathione synthesis

MUGLIA, C., D.H. GRASSO, AND O.M. AGUILAR

MICROBIOLOGY

SGM Society General Microbiology UK

Año: 2007 vol. 153 p. 1286 - 1296

0026-2617

Rhizobium tropici CIAT899 displays intrinsic tolerance to acidity, and efficiently nodulatesPhaseolus vulgaris at low pH. By characterizing a gshB mutant strain, glutathione has beenpreviously demonstrated to be essential for R. tropici tolerance to acid stress. The wild-type gshBgene region has been cloned and its transcription profile has been characterized by usingquantitative real-time PCR and transcriptional gene fusions. Activation of the gshB gene underacid-stress conditions was demonstrated. gshB is also induced by UV irradiation. Upstream fromgshB a putative s70 promoter element and an inverted repeat sequence were identified, which areproposed to be involved in expression under neutral and acidic conditions, respectively. Gelretardation assays indicate that transcription in acid conditions may involve protein binding to anupstream regulatory region