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Revealing the roles of y4wF and tidC genes in Rhizobium tropici CIAT 899: biosynthesis of indolic compounds and impact on symbiotic properties
- Source :
- Archives of Microbiology. 201:171-183
- Publication Year :
- 2018
- Publisher :
- Springer Science and Business Media LLC, 2018.
-
Abstract
- Rhizobium tropici CIAT 899 is a strain known by its ability to nodulate a broad range of legume species, to synthesize a variety of Nod factors, its tolerance of abiotic stresses, and its high capacity to fix atmospheric N2, especially in symbiosis with common bean (Phaseolus vulgaris L.). Genes putatively related to the synthesis of indole acetic acid (IAA) have been found in the symbiotic plasmid of CIAT 899, in the vicinity of the regulatory nodulation gene nodD5, and, in this study, we obtained mutants for two of these genes, y4wF and tidC (R. tropiciindole-3-pyruvic acid decarboxylase), and investigated their expression in the absence and presence of tryptophan (TRP) and apigenin (API). In general, mutations of both genes increased exopolysaccharide (EPS) synthesis and did not affect swimming or surface motility; mutations also delayed nodule formation, but increased competitiveness. We found that the indole-3-acetamide (IAM) pathway was active in CIAT 899 and not affected by the mutations, and-noteworthy-that API was required to activate the tryptamine (TAM) and the indol-3-pyruvic acid (IPyA) pathways in all strains, particularly in the mutants. High up-regulation of y4wF and tidC genes was observed in both the wild-type and the mutant strains in the presence of API. The results obtained revealed an intriguing relationship between IAA metabolism and nod-gene-inducing activity in R. tropici CIAT 899. We discuss the IAA pathways, and, based on our results, we attribute functions to the y4wF and tidC genes of R. tropici.
- Subjects :
- Tryptamine
Rhizobium tropici
Indoles
Carboxy-Lyases
Mutant
Biochemistry
Microbiology
03 medical and health sciences
chemistry.chemical_compound
Plasmid
Biosynthesis
Symbiosis
Genetics
Molecular Biology
Gene
030304 developmental biology
Phaseolus
0303 health sciences
Indoleacetic Acids
biology
030306 microbiology
Polysaccharides, Bacterial
Tryptophan
food and beverages
General Medicine
biology.organism_classification
chemistry
Genes, Bacterial
Mutation
Subjects
Details
- ISSN :
- 1432072X and 03028933
- Volume :
- 201
- Database :
- OpenAIRE
- Journal :
- Archives of Microbiology
- Accession number :
- edsair.doi.dedup.....7509682fa309e5bd3284361d52dacd7d