Abstract
Early stages in the infection of leguminous plants by Rhizobium spp. are restricted at low pH and are further influenced by the presence of Ca and Al ions. In the experiments reported here, transcriptional and translational fusions of the Escherichia coli lacZ gene to Rhizobium leguminosarum biovar trifolii nodulation (nod) genes were used to investigate the effects of pH and of Ca and Al ions on nod gene expression. The regulatory nodD gene in R. leguminosarum biovar trifolii was constitutively expressed at a range of pH levels between 4.8 and 6.5, and expression was not affected by the addition of 22.5 μM Al or 1,250 μM Ca. Induction of expression of nodA, nodF, and region II nodulation genes in the presence of 5 × 10−7 M 7,4′-dihydroxyflavone was restricted at a pH of <5.7 and was extremely poor at pH 4.8. Induction of nodA expression was further restricted by 22.5 μM Al over a range of pH levels but was increased in the presence of Ca. The addition of Ca, however, only slightly alleviated the Al-mediated inhibition of nodA induction. Induction of expression of nodA was equally sensitive to low pH in three strains of R. leguminosarum biovar trifolii (ANU845, ANU815, and ANU1184), which exhibited contrasting growth abilities in solution culture at a pH of <5.0. Aluminum, however, differentially affected the induction of nodA in these three strains, with the most Al-tolerant strain for growth being the most Al-sensitive strain for nod gene induction. Poor induction of expression of nodulation genes in R. leguminosarum biovar trifolii was considered to be an important factor contributing to the acid-sensitive step of legume root infection.
Full text
PDF







Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bhuvaneswari T. V., Bhagwat A. A., Bauer W. D. Transient susceptibility of root cells in four common legumes to nodulation by rhizobia. Plant Physiol. 1981 Nov;68(5):1144–1149. doi: 10.1104/pp.68.5.1144. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Castilho B. A., Olfson P., Casadaban M. J. Plasmid insertion mutagenesis and lac gene fusion with mini-mu bacteriophage transposons. J Bacteriol. 1984 May;158(2):488–495. doi: 10.1128/jb.158.2.488-495.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dazzo F. B., Hubbell D. H. Cross-reactive antigens and lectin as determinants of symbiotic specificity in the Rhizobium-clover association. Appl Microbiol. 1975 Dec;30(6):1017–1033. doi: 10.1128/am.30.6.1017-1033.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Djordjevic M. A., Redmond J. W., Batley M., Rolfe B. G. Clovers secrete specific phenolic compounds which either stimulate or repress nod gene expression in Rhizobium trifolii. EMBO J. 1987 May;6(5):1173–1179. doi: 10.1002/j.1460-2075.1987.tb02351.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Djordjevic M. A., Zurkowski W., Shine J., Rolfe B. G. Sym plasmid transfer to various symbiotic mutants of Rhizobium trifolii, R. leguminosarum, and R. meliloti. J Bacteriol. 1983 Dec;156(3):1035–1045. doi: 10.1128/jb.156.3.1035-1045.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hong G. F., Burn J. E., Johnston A. W. Evidence that DNA involved in the expression of nodulation (nod) genes in Rhizobium binds to the product of the regulatory gene nodD. Nucleic Acids Res. 1987 Dec 10;15(23):9677–9690. doi: 10.1093/nar/15.23.9677. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horvath B., Bachem C. W., Schell J., Kondorosi A. Host-specific regulation of nodulation genes in Rhizobium is mediated by a plant-signal, interacting with the nodD gene product. EMBO J. 1987 Apr;6(4):841–848. doi: 10.1002/j.1460-2075.1987.tb04829.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lowther W. L., Loneragan J. F. Calcium and Nodulation in Subterranean Clover (Trifolium subterraneum L.). Plant Physiol. 1968 Sep;43(9):1362–1366. doi: 10.1104/pp.43.9.1362. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mulligan J. T., Long S. R. Induction of Rhizobium meliloti nodC expression by plant exudate requires nodD. Proc Natl Acad Sci U S A. 1985 Oct;82(19):6609–6613. doi: 10.1073/pnas.82.19.6609. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Peters N. K., Frost J. W., Long S. R. A plant flavone, luteolin, induces expression of Rhizobium meliloti nodulation genes. Science. 1986 Aug 29;233(4767):977–980. doi: 10.1126/science.3738520. [DOI] [PubMed] [Google Scholar]
- Plazinski J., Cen Y. H., Rolfe B. G. General method for the identification of plasmid species in fast-growing soil microorganisms. Appl Environ Microbiol. 1985 Apr;49(4):1001–1003. doi: 10.1128/aem.49.4.1001-1003.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rossen L., Shearman C. A., Johnston A. W., Downie J. A. The nodD gene of Rhizobium leguminosarum is autoregulatory and in the presence of plant exudate induces the nodA,B,C genes. EMBO J. 1985 Dec 16;4(13A):3369–3373. doi: 10.1002/j.1460-2075.1985.tb04092.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rostas K., Kondorosi E., Horvath B., Simoncsits A., Kondorosi A. Conservation of extended promoter regions of nodulation genes in Rhizobium. Proc Natl Acad Sci U S A. 1986 Mar;83(6):1757–1761. doi: 10.1073/pnas.83.6.1757. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schofield P. R., Watson J. M. DNA sequence of Rhizobium trifolii nodulation genes reveals a reiterated and potentially regulatory sequence preceding nodABC and nodFE. Nucleic Acids Res. 1986 Apr 11;14(7):2891–2903. doi: 10.1093/nar/14.7.2891. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Surin B. P., Downie J. A. Characterization of the Rhizobium leguminosarum genes nodLMN involved in efficient host-specific nodulation. Mol Microbiol. 1988 Mar;2(2):173–183. doi: 10.1111/j.1365-2958.1988.tb00019.x. [DOI] [PubMed] [Google Scholar]
- Török I., Kondorosi E., Stepkowski T., Pósfai J., Kondorosi A. Nucleotide sequence of Rhizobium meliloti nodulation genes. Nucleic Acids Res. 1984 Dec 21;12(24):9509–9524. doi: 10.1093/nar/12.24.9509. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zaat S. A., Wijffelman C. A., Spaink H. P., van Brussel A. A., Okker R. J., Lugtenberg B. J. Induction of the nodA promoter of Rhizobium leguminosarum Sym plasmid pRL1JI by plant flavanones and flavones. J Bacteriol. 1987 Jan;169(1):198–204. doi: 10.1128/jb.169.1.198-204.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]