Journal article
ActP controls copper homeostasis in Rhizobium leguminosarum bv. viciae and Sinorhizobium meliloti preventing low pH-induced copper toxicity
Molecular Microbiology, Vol.43(4), pp.981-991
2002
Abstract
Two 'calcium-irreparable' acid-sensitive mutants were identified after mutagenizing Rhizobium leguminosarum bv. viciae and Sinorhizobium meliloti with Tn5. Each mutant contains a single copy of the transposon which, inserted within the actP gene, prevents expression of a P-type ATPase that belongs to the CPx heavy metal-transporting subfamily. Here, we show that both actP-knockout mutants show sensitivity to copper; omission of this heavy metal from low pH-buffered media restores acid tolerance to these strains. Furthermore, complementation of the mutant phenotype requires only the actP gene. An actP-gusA fusion in R. leguminosarum was transcriptionally regulated by copper in a pH-dependent manner. Downstream to actP in both organisms is the hmrR gene that encodes a heavy metal-responsive regulator (HmrR) that belongs to the merR class of regulatory genes. Insertional inactivation of hmrR abolished transcriptional activation of actP by copper ions and increased the basal level of its expression in their absence. These observations suggest that HmrR can regulate actP transcription positively and negatively. We show that copper homeostasis is an essential mechanism for the acid tolerance of these root nodule bacteria since it prevents this heavy metal from becoming overtly toxic in acidic conditions.
Details
- Title
- ActP controls copper homeostasis in Rhizobium leguminosarum bv. viciae and Sinorhizobium meliloti preventing low pH-induced copper toxicity
- Authors/Creators
- W.G. Reeve (Author/Creator)R.P. Tiwari (Author/Creator)N.B. Kale (Author/Creator)M.J. Dilworth (Author/Creator)A.R. Glenn (Author/Creator)
- Publication Details
- Molecular Microbiology, Vol.43(4), pp.981-991
- Publisher
- Blackwell Publishing
- Identifiers
- 991005541674407891
- Copyright
- (c) Blackwell Publishing
- Murdoch Affiliation
- Centre for Rhizobium Studies
- Language
- English
- Resource Type
- Journal article
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Source: InCites
Metrics
66 Record Views
InCites Highlights
These are selected metrics from InCites Benchmarking & Analytics tool, related to this output
- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 3 Agriculture, Environment & Ecology
- 3.97 Plant Pathology
- 3.97.892 Rhizobium-Legume Symbiosis
- Web Of Science research areas
- Biochemistry & Molecular Biology
- Microbiology
- ESI research areas
- Microbiology