Isolation of salt-sensitive mutants from Sinorhizobium meliloti and characterization of genes involved in salt tolerance.
OBJECTIVE
The purpose of our research is to isolate salt-sensitive mutants and to study the genes involved in salt tolerance of the salt-tolerant bacterium Sinorhizobium meliloti 042BM.


METHODS
Wild type S. meliloti 042BM bacteria are able to grow at a NaCl concentration of 0.6 mol l(-1). A transposon Tn5-1063a mutagenesis library of S. meliloti 042BM was constructed and eight salt-sensitive mutants were isolated, which were unable to growth on FY plates containing 0.4 mol l(-1) NaCl.


CONCLUSIONS
Our interest is to provide information about the mechanism of salt tolerance in bacteria by studying the genes involved in salt tolerance. Here, seven different genes were identified. These genes include omp10 encoding a cell outer membrane protein, relA encoding (p)ppGpp synthetase, greA encoding a transcription cleavage factor, nuoL encoding NADH dehydrogenase I chain L transmembrane protein, a putative nuclease/helicase gene and two unknown genes. Based on these findings, we suggest that the regulation of salt tolerance of S. meliloti 042BM is complex and on several levels.
Department of Microbiology, College of Biological Sciences, China Agricultural University, Beijing, PR China.
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W
Wei
J
J
Jiang
X
X
Li
L
L
Wang
S S
SS
Yang
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D000455:Medicago sativa / Q000382:microbiology*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D009997:Osmotic Pressure; D017422:Sequence Analysis, DNA; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D012965:Sodium Chloride / Q000378:metabolism*
D001426:Bacterial Proteins; D003470:Culture Media; D004251:DNA Transposable Elements; D012965:Sodium Chloride