In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 71, No. 10 ( 2005-10), p. 5969-5982
Abstract:
A regulatory network of Sinorhizobium meliloti genes involved in adaptation to iron-limiting conditions and the involvement of the rhizobial iron regulator gene ( rirA ) were analyzed by mutation and microarray analyses. A constructed S. meliloti rirA mutant exhibited growth defects and enhanced H 2 O 2 sensitivity in the presence of iron, but symbiotic nitrogen fixation was not affected. To identify iron-responsive and RirA-regulated S. meliloti genes, a transcriptome approach using whole-genome microarrays was used. Altogether, 45 genes were found to be jointly derepressed by mutation of rirA and under different iron-limited conditions. As expected, a number of genes involved in iron transport (e.g., hmuPSTU , shmR , rhbABCDEF , rhtX , and rhtA ) and also genes with predicted functions in energy metabolism (e.g., fixN3 , fixP3 , and qxtAB ) and exopolysaccharide production (e.g., exoY and exoN ) were found in this group of genes. In addition, the iron deficiency response of S. meliloti also involved rirA -independent expression changes, including repression of the S. meliloti flagellar regulon. Finally, the RirA modulon also includes genes that are not iron responsive, including a gene cluster putatively involved in Fe-S cluster formation ( sufA , sufS , sufD , sufC , and sufB ).
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.71.10.5969-5982.2005
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2005
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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