Effects of Temperature Stress on Bean-Nodulating Rhizobium Strains

• DOI: 10.1128/aem.60.4.1206-1212.1994
• Publication Date: 2020-01-01T04:56:33Z
• Authors: Jan Michiels; Christel Verreth; Jos Vanderleyden
• Keywords: Strain (injury); Thermal shock

High soil temperatures in tropical areas limit nodulation and dinitrogen fixation by strains of Rhizobium. Several heat-tolerant bean-nodulating Rhizobium have been isolated previously. However, the basis their resistance to heat remains unknown. In this study, we compared effects on symbiotic nitrogen fixation, cell survival, amino acid uptake, protein synthesis a (CIAT899) heat-sensitive (CNPAF512) strain. Acetylene reduction activity nodulated roots excised from unstressed plants was strongly diminished at 35 or 40°C when were either CIAT899 CNPAF512. When these tested under free-living conditions, survival as well kinetics l -[ S]methionine uptake indicated higher tolerance than CNPAF512 thermal stress. The shock proteins detected both strains, although different temperatures. Increased 14 6 observed 40 45°C, respectively. A approximately 21 kDa, which strongest upon temperature shift up, also conserved several other rhizobia. Acquired thermotolerance shown depend synthesis.