Pleiotropic effects of a rel mutation on stress survival of Rhizobium etli CNPAF512

• DOI: 10.1186/1471-2180-8-219
• Publication Date: 2008-12-11T07:13:20Z
• Authors: Kristien Braeken; Maarten Fauvart; Maarten Vercruysse; Serge Beullens; Ivo Lambrichts; Jan Michiels
• Keywords: Wild type; Strain (injury)

Abstract Background The rel gene of Rhizobium etli ( Ret ), the nodulating endosymbiont common bean plant, determines cellular level alarmone (p)ppGpp and was previously shown to affect free-living growth symbiosis. Here, we demonstrate its role in adaptation survival response various stresses. Results Growth R. mutant strongly reduced or abolished presence elevated NaCl levels at 37°C, compared wild type. In addition, depending on cell density, decreased exponentially growing stationary phase cells obtained after H 2 O , heat shock wild-type strain. Survival unstressed cultures differentially affected medium used. Colony forming units (CFU) continuously minimal supplemented with succinate, whereas stabilised higher CFU levels. Microscopic examination indicated that unable reach typical coccoid morphology type cultures. Assessment stress resistance re-isolated bacteroids showed increased sensitivity a slightly temperature (45°C) shock, bacteroids. Conclusion is an important factor regulating rhizobial physiology, during as well symbiotic conditions. Additionally, differential responses several stresses applied exponential point essential physiological differences between different states.