Open AccessNitrogen regulation in Sinorhizobium meliloti probed with whole genome arrays
Author(s) -
Davalos Marcela,
Fourment Joëlle,
Lucas Antoine,
Bergès Hélène,
Kahn Daniel
Publication year - 2004
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2004.09.041
Subject(s) - sinorhizobium meliloti , glutamate synthase , operon , glutamine synthetase , biochemistry , biology , bacteria , gene , chemistry , microbiology and biotechnology , glutamine , genetics , amino acid , mutant
Using whole genome arrays, we systematically investigated nitrogen regulation in the plant symbiotic bacterium Sinorhizobium meliloti . The use of glutamate instead of ammonium as a nitrogen source induced nitrogen catabolic genes independently of the carbon source, including two glutamine synthetase genes, various aminoacid transporters and the glnKamtB operon. These responses depended on both the ntrC and glnB nitrogen regulators. Glutamate repressible genes included glutamate synthase and a H + ‐translocating pyrophosphate synthase. The smc01041 ‐ ntrBC operon was negatively autoregulated in a glnB ‐dependent fashion, indicating an involvement of phosphorylated NtrC. In addition to the nitrogen response, glutamate remodelled expression of carbon metabolism by inhibiting expression of the Entner–Doudoroff and pentose phosphate pathways, and by stimulating gluconeogenetic genes independently of ntrC .