Rhizobium leguminosarum methyl-accepting chemotaxis protein genes are down-regulated in the pea nodule

• Published in: Archives of microbiology Vol. 182; no. 6; pp. 505 - 513
• Main Authors: Yost, C.K, Del Bel, K.L, Quandt, J, Hynes, M.F
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-12-2004; Berlin Springer Nature B.V
• Subjects: Artificial Gene Fusion; Bacteria; bacterial proteins; Bacterial Proteins - analysis; Bacterial Proteins - biosynthesis; Bacterial Proteins - genetics; Bacteriology; bacteroids; Biological and medical sciences; Blotting, Western; Carbon sources; chemotaxis; Down-Regulation; Environmental conditions; Fundamental and applied biological sciences. Psychology; gene down-regulation; gene expression regulation; Gene Expression Regulation, Bacterial; gene fusion; Growth conditions; Legumes; mcp gene; Membrane Proteins - analysis; Membrane Proteins - biosynthesis; Membrane Proteins - genetics; Methyl-Accepting Chemotaxis Proteins; Microbiology; Miscellaneous; Nitrogen fixation; Nitrogen Fixation - genetics; nitrogen-fixing bacteria; nodulation; Oxygen - metabolism; peas; Pisum sativum; Pisum sativum - microbiology; Rhizobium leguminosarum; Rhizobium leguminosarum - genetics; Rhizobium leguminosarum - physiology; root nodules; structural genes; Succinates - metabolism; Symbiosis; Microbiology; Gene regulation; Chemotaxis; Rhizobium leguminosarum; Chemoreceptor; Protein; Grain legume; Regulation(control); Rhizobia; Leguminosae; Gene; Dicotyledones; Pisum sativum; Modulation; Angiospermae; Methyl-accepting chemotaxis proteins; Bacteria; High protein crop; Spermatophyta; Rhizobiaceae; Bacteroid; Chemoreceptors
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-004-0736-7

Regulation of methyl-accepting chemotaxis protein (MCP) genes of Rhizobium leguminosarum was studied under symbiotic conditions. Transcriptional fusions using both β-galactosidase and β-glucuronidase genes within two different mcp genes demonstrated that mcp expression decreased significantly during nodulation. Immunoblots using an anti-MCP antibody detected MCPs in free-living cells but not in bacteroids. Down-regulation during nodulation was not dependent upon known regulatory proteins involved in induction of expression of genes involved in nitrogen fixation. Environmental conditions found in the bacteroid that may trigger down-regulation were investigated by growing free-living cultures under a variety of growth conditions. Growth under low oxygen concentration or using succinate as a sole carbon source did not lower expression of the mcp gene fusions.