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Monounsaturated fatty acid aerobic synthesis in Bradyrhizobium TAL1000 peanut‐nodulating is affected by temperature
Author(s) -
Paulucci N.S.,
Medeot D.B.,
Woelke M.,
Dardanelli M.S.,
Lema M.G.
Publication year - 2013
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12155
Subject(s) - fatty acid desaturase , bradyrhizobium , biochemistry , biology , fatty acid , escherichia coli , heat shock , bacteria , strain (injury) , heat shock protein , bioprocess , food science , chemistry , gene , polyunsaturated fatty acid , genetics , paleontology , rhizobium , anatomy
Aims The aim of this work was to clarify the mechanism of monounsaturated fatty acid ( MUFA ) synthesis in Bradyrhizobium TAL 1000 and the effect of high temperature on this process. Methods and Results Bradyrhizobium TAL 1000 was exposed to a high growth temperature and heat shock, and fatty acid composition and synthesis were tested. To determine the presence of a possible desaturase, a gene was identify and overexpressed in Escherichia coli . The desaturase expression was detected by RT ‐ PCR and Western blotting. In B . TAL 1000, an aerobic mechanism for MUFA synthesis was detected. Desaturation was decreased by high growth temperature and by heat shock. Two hours of exposure to 37°C were required for the change in MUFA levels. A potential ∆9 desaturase gene was identified and successfully expressed in E. coli . A high growth temperature and not heat shock reduced transcript and protein desaturase levels in rhizobial strain. Conclusions In B . TAL 1000, the anaerobic MUFA biosynthetic pathway is supplemented by an aerobic mechanism mediated by desaturase and is down‐regulated by temperature to maintain membrane fluidity under stressful conditions. Significance and Impact of the Study This knowledge will be useful for developing strategies to improve a sustainable practice of this bacterium under stress and to enhance the bioprocess for the inoculants' manufacture.