Editor: Kornelia Smalla
Most heat-tolerant rhizobia show high induction of major chaperone genes upon stress
Article first published online: 12 NOV 2010
© 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Ecology
Volume 75, Issue 1, pages 28–36, January 2011
How to Cite
Alexandre, A. and Oliveira, S. (2011), Most heat-tolerant rhizobia show high induction of major chaperone genes upon stress. FEMS Microbiology Ecology, 75: 28–36. doi: 10.1111/j.1574-6941.2010.00993.x
- Issue published online: 6 DEC 2010
- Article first published online: 12 NOV 2010
- Accepted manuscript online: 20 OCT 2010 10:03AM EST
- Received 9 February 2010; revised 12 August 2010; accepted 10 October 2010.Final version published online 12 November 2010.
- temperature stress;
- gene expression;
The aims of this study were to evaluate the temperature stress tolerance of chickpea rhizobia and to investigate whether tolerance is related to the species or the site of origin of the isolates. Additionally, the molecular bases of temperature stress tolerance in rhizobia were investigated, by comparing the expression of chaperone genes dnaKJ and groESL in thermotolerant and thermosensitive isolates. Tolerance to cold, heat and heat shock was evaluated for 53 mesorhizobia obtained from several provinces of Portugal and assigned to different species. Associations between isolates' tolerance phenotype and several provinces of origin were found. Some species groups were found to differ significantly in their ability to tolerate temperature stress. Analysis of the dnaK and groESL expression by Northern hybridization, using isolates from three species groups, showed an increase in the transcripts levels with heat, but not with cold stress. Interestingly, a higher induction of chaperone genes was detected in heat-tolerant isolates when compared with that of sensitive isolates of the same species. To our knowledge, this is the first analysis of chaperone genes' expression comparing tolerant and sensitive strains. The present study suggests a relationship between higher transcriptional induction of major chaperone genes and higher tolerance to heat in rhizobia.