Response to temperature stress in rhizobia

Abstract

It is well established that soil is a challenging environment for bacteria, where conditions may change rapidly and bacteria have to acclimate and adapt in order to survive. Rhizobia are an important group of soil bacteria due to their ability to establish atmospheric nitrogen-fixing symbioses with many legume species. Some of these legumes are used to feed either humans or cattle and therefore the use of rhizobia can reduce the need for synthetic N-fertilizers. Several environmental factors shape the composition and the activity of rhizobia populations in the rhizosphere. Soil pH and temperature are often considered to be the major abiotic factors in determining the bacterial community diversity. The present review focuses on the current knowledge on the molecular bases of temperature stress response in rhizobia. The effects of temperature stress in the legume-rhizobia symbioses are also addressed.

Keywords::

• Heat stress
• cold stress
• symbiosis
• chaperone
• biological nitrogen fixation

Acknowledgments

The authors thank B. R. Glick for the careful reading of the manuscript.

Declaration of interest

Financial support was provided by Fundação para a Ciência e Tecnologia (FCT), including the research project FCOMP-01-0124-FEDER-007091 and post-doctoral fellowship SFRH/BPD/73243/2010 to A.Alexandre.