Abstract
Bradyrhizobium japonicum is a Gram-negative soil bacterium that can fix nitrogen into ammonia by developing a symbiotic relationship with the soybean plant. MocR proteins make up a subfamily of GntR superfamily, one of the most widely distributed and prolific groups of the helix-turn-helix transcription factors. In this study, we constructed a mutant strain for mocR (blr6977) to investigate its role in cellular processes and symbiosis in B. japonicum. Although growth rate and morphology of the mutant were indistinguishable from those of the wild type, the mutant showed significant differences in motility and attachment (i.e., biofilm formation) from the wild type. The mutant displayed a decrease in biofilm formation, but was more motile than the wild type. The inactivation of mocR did not affect the number of nodules on soybean roots, but caused delayed nodulation. Delayed nodulation intrigued us to study competitiveness of the mutant infecting soybeans. The mutant was less competitive than the wild type, indicating that delayed nodulation might be due to competitiveness. Gene expressions of other MocR subfamily members were also compared between the wild type and mutant strains. None of the mocR-like genes examined in this study were differentially expressed between both strains.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Ames, P. and Bergman, K. 1981. Competitive advantage provided by bacterial motility in the formation of nodules by Rhizobium meliloti. J. Bacteriol. 148, 728–908.
Ballering, K.S., Kristich, C.J., Grindle, S.M., Oromendia, A., Beattie, D.T., and Dunny, G.M. 2009. Functional genomics of Enterococcus faecalis: multiple novel genetic determinants for biofilm formation in the core genome. J. Bacteriol. 191, 2806–2814.
Belitsky, B.R. 2004. Bacillus subtilis GabR, a protein with DNA-binding and aminotransferase domains, is a PLP-dependent transcriptional regulator. J. Mol. Biol. 340, 655–664.
Bittner, M., Butow, R., DeRisi, J., Diehn, M., Eberwine, J., Epstein, C.B., Glynne, R., Grimmond, S., Ideker, T., Kacharmina, J.E., et al. 2003. Expression analysis of RNA. pp. 101–288. In Bowtell, D. and Sambrook, J. (eds.), DNA Microarrays: A Molecular Cloning Manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA.
Bogino, P.C., Oliva Mde, L., Sorroche, F.G., and Giordano, W. 2013. The role of bacterial biofilms and surface components in plantbacterial associations. Int. J. Mol. Sci. 14, 15838–15859.
Bramucci, E., Milano, T., and Pascarella, S. 2011. Genomic distribution and heterogeneity of MocR-like transcriptional factors containing a domain belonging to the superfamily of the pyridoxal-5′-phosphate dependent enzymes of fold type I. Biochem. Biophys. Res. Commun. 415, 88–93.
Broughton, W.J. and Dilworth, M.J. 1971. Control of leghaemoglobin synthesis in snake beans. Biochem. J. 125, 1075–1080.
Caetano-Anolles, G., Wall, L.G., De Micheli, A.T., Macchi, E.M., Bauer, W.D., and Favelukes, G. 1988. Role of motility and chemotaxis in efficiency of nodulation by Rhizobium meliloti. Plant Physiol. 86, 1228–1235.
Caiazza, N.C., Merritt, J.H., Brothers, K.M., and O’Toole, G.A. 2007. Inverse regulation of biofilm formation and swarming motility by Pseudomonas aeruginosa PA14. J. Bacteriol. 189, 3603–3612.
Chang, W.S., Franck, W.L., Cytryn, E., Jeong, S., Joshi, T., Emerich, D.W., Sadowsky, M.J., Xu, D., and Stacey, G. 2007. An oligonucleotide microarray resource for transcriptional profiling of Bradyrhizobium japonicum. Mol. Plant-Microbe Interact. 20, 1298–1307.
Franck, W.L., Chang, W.S., Qiu, J., Sugawara, M., Sadowsky, M.J., Smith, S.A., and Stacey, G. 2008. Whole-genome transcriptional profiling of Bradyrhizobium japonicum during chemoautotrophic growth. J. Bacteriol. 190, 6697–6705.
Fujita, Y. and Fujita, T. 1987. The gluconate operon gnt of Bacillus subtilis encodes its own transcriptional negative regulator. Proc. Nat. Acad. Sci. USA 84, 4524–4528.
Göttfert, M., Holzhauser, D., Bani, D., and Hennecke, H. 1992. Structural and functional analysis of two different nodD genes in Bradyrhizobium japonicum USDA110. Mol. Plant-Microbe Interact. 5, 257–265.
Haine, V., Sinon, A., Van Steen, F., Rousseau, S., Dozot, M., Lestrate, P., Lambert, C., Letesson, J.J., and De Bolle, X. 2005. Systematic targeted mutagenesis of Brucella melitensis 16M reveals a major role for GntR regulators in the control of virulence. Infect. Immun. 73, 5578–5586.
Hillerich, B. and Westpheling, J. 2006. A new GntR family transcriptional regulator in Streptomyces coelicolor is required for morphogenesis and antibiotic production and controls transcription of an ABC transporter in response to carbon source. J. Bacteriol. 188, 7477–7487.
Hoskisson, P.A. and Rigali, S. 2009. Chapter 1: Variation in form and function the helix-turn-helix regulators of the GntR superfamily. Adv. Appl. Microbiol. 69, 1–22.
Jaques, S. and McCarter, L.L. 2006. Three new regulators of swarming in Vibrio parahaemolyticus. J. Bacteriol. 188, 2625–2635.
Jochmann, N., Gotker, S., and Tauch, A. 2011. Positive transcriptional control of the pyridoxal phosphate biosynthesis genes pdxST by the MocR-type regulator PdxR of Corynebacterium glutamicum ATCC 13032. Microbiology 157, 77–88.
Kaneko, T., Nakamura, Y., Sato, S., Minamisawa, K., Uchiumi, T., Sasamoto, S., Watanabe, A., Idesawa, K., Iriguchi, M., Kawashima, K., et al. 2002. Complete genomic sequence of nitrogen-fixing symbiotic bacterium Bradyrhizobium japonicum USDA110. DNA Res. 9, 189–197.
Kovach, M.E., Phillips, R.W., Elzer, P.H., Roop, R.M., 2nd, and Peterson, K.M. 1994. pBBR1MCS: a broad-host-range cloning vector. BioTechniques 16, 800–802.
Lee, H.I., In, Y.H., Jeong, S.Y., Jeon, J.M., Noh, J.G., So, J.S., and Chang, W.S. 2014. Inactivation of the lpcC gene alters surfacerelated properties and symbiotic capability of Bradyrhizobium japonicum. Lett. Appl. Microbiol. 59, 9–16.
Lee, Y.W., Jeong, S.Y., In, Y.H., Kim, K.Y., So, J.S., and Chang, W.S. 2010. Lack of O-polysaccharide enhances biofilm formation by Bradyrhizobium japonicum. Lett. Appl. Microbiol. 50, 452–456.
Lee, H.I., Lee, J.H., Park, K.H., Sangurdekar, D., and Chang, W.S. 2012. Effect of soybean coumestrol on Bradyrhizobium japonicum nodulation ability, biofilm formation, and transcriptional profile. Appl. Environ. Microbiol. 78, 2896–2903.
Leong, S.A., Ditta, G.S., and Helinski, D.R. 1982. Heme biosynthesis in Rhizobium. Identification of a cloned gene coding for deltaaminolevulinic acid synthetase from Rhizobium meliloti. J. Biol. Chem. 257, 8724–8730.
Liao, S., Bitoun, J.P., Nguyen, A.H., Bozner, D., Yao, X., and Wen, Z.T. 2015. Deficiency of PdxR in Streptococcus mutans affects vitamin B6 metabolism, acid tolerance response and biofilm formation. Mol. Oral Microbiol. 30, 255–268.
Loh, J.T., Yuen-Tsai, J.P., Stacey, M.G., Lohar, D., Welborn, A., and Stacey, G. 2001. Population density-dependent regulation of the Bradyrhizobium japonicum nodulation genes. Mol. Microbiol. 42, 37–46.
Lord, D.M., Uzgoren Baran, A., Soo, V.W., Wood, T.K., Peti, W., and Page, R. 2014. McbR/YncC: implications for the mechanism of ligand and DNA binding by a bacterial GntR transcriptional regulator involved in biofilm formation. Biochemistry 53, 7223–7231.
Merritt, J.H., Brothers, K.M., Kuchma, S.L., and O’Toole, G.A. 2007. SadC reciprocally influences biofilm formation and swarming motility via modulation of exopolysaccharide production and flagellar function. J. Bacteriol. 189, 8154–8164.
Rigali, S., Derouaux, A., Giannotta, F., and Dusart, J. 2002. Subdivision of the helix-turn-helix GntR family of bacterial regulators in the FadR, HutC, MocR, and YtrA subfamilies. J. Biol. Chem. 277, 12507–12515.
Rossbach, S., Kulpa, D.A., Rossbach, U., and de Bruijn, F.J. 1994. Molecular and genetic characterization of the rhizopine catabolism (mocABRC) genes of Rhizobium meliloti L5-30. Mol. Gen. Genet. 245, 11–24.
Sadowsky, M.J., Cregan, P.B., Gottfert, M., Sharma, A., Gerhold, D., Rodriguez-Quinones, F., Keyser, H.H., Hennecke, H., and Stacey, G. 1991. The Bradyrhizobium japonicum nolA gene and its involvement in the genotype-specific nodulation of soybeans. Proc. Nat. Acad. Sci. USA 88, 637–641.
Sadowsky, M.J., Tully, R.E., Cregan, P.B., and Keyser, H.H. 1987. Genetic diversity in Bradyrhizobium japonicum serogroup 123 and its relation to genotype-specific nodulation of soybean. Appl. Environ. Microbiol. 53, 2624–2630.
Sambrook, J., Fritsch, E.F., and Maniatis, T. 1989. Molecular Cloning: a Laboratory Manual. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., USA.
So, J.S., Hodgson, A.L., Haugland, R., Leavitt, M., Banfalvi, Z., Nieuwkoop, A.J., and Stacey, G. 1987. Transposon-induced symbiotic mutants of Bradyrhizobium japonicum: isolation of two gene regions essential for nodulation. Mol. Gen. Genet. 207, 15–23.
Tanaka, Y., Takemoto, N., Ito, T., Teramoto, H., Yukawa, H., and Inui, M. 2014. Genome-wide analysis of the role of global transcriptional regulator GntR1 in Corynebacterium glutamicum. J. Bacteriol. 196, 3249–3258.
van Rhijn, P. and Vanderleyden, J. 1995. The Rhizobium-plant symbiosis. Microbiol. Rev. 59, 124–142.
Vincent, J.M. 1970. A manual for the practice study of root-nodule bacteria. Blackwell Scientific.
Wang, Y., Chen, A.M., Yu, A.Y., Luo, L., Yu, G.Q., Zhu, J.B., and Wang, Y.Z. 2008. The GntR-type regulators gtrA and gtrB affect cell growth and nodulation of Sinorhizobium meliloti. J. Microbiol. 46, 137–145.
Wiethaus, J., Schubert, B., Pfander, Y., Narberhaus, F., and Masepohl, B. 2008. The GntR-like regulator TauR activates expression of taurine utilization genes in Rhodobacter capsulatus. J. Bacteriol. 190, 487–493.
Windgassen, M., Urban, A., and Jaeger, K.E. 2000. Rapid gene inactivation in Pseudomonas aeruginosa. FEMS Microbiol. Lett. 193, 201–205.
Yanisch-Perron, C., Vieira, J., and Messing, J. 1985. Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors. Gene 33, 103–119.
Author information
Authors and Affiliations
Corresponding author
Additional information
Supplemental material for this article may be found at http://www.springerlink.com/content/120956.
Electronic supplementary material
Rights and permissions
About this article
Cite this article
Taw, M.N., Lee, HI., Lee, SH. et al. Characterization of MocR, a GntR-like transcriptional regulator, in Bradyrhizobium japonicum: its impact on motility, biofilm formation, and soybean nodulation. J Microbiol. 53, 518–525 (2015). https://doi.org/10.1007/s12275-015-5313-z
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12275-015-5313-z