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Increased production of the exopolysaccharide succinoglycan enhances Sinorhizobium meliloti 1021 symbiosis with the host plant Medicago truncatula.
- Source :
-
Journal of bacteriology [J Bacteriol] 2012 Aug; Vol. 194 (16), pp. 4322-31. Date of Electronic Publication: 2012 Jun 08. - Publication Year :
- 2012
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Abstract
- The nitrogen-fixing rhizobial symbiont Sinorhizobium meliloti 1021 produces acidic symbiotic exopolysaccharides that enable it to initiate and maintain infection thread formation on host legume plants. The exopolysaccharide that is most efficient in mediating this process is succinoglycan (exopolysaccharide I [EPSI]), a polysaccharide composed of octasaccharide repeating units of 1 galactose and 7 glucose residues, modified with succinyl, acetyl, and pyruvyl substituents. Previous studies had shown that S. meliloti 1021 mutants that produce increased levels of succinoglycan, such as exoR mutants, are defective in symbiosis with host plants, leading to the hypothesis that high levels of succinoglycan production might be detrimental to symbiotic development. This study demonstrates that increased succinoglycan production itself is not detrimental to symbiotic development and, in fact, enhances the symbiotic productivity of S. meliloti 1021 with the host plant Medicago truncatula cv. Jemalong A17. Increased succinoglycan production was engineered by overexpression of the exoY gene, which encodes the enzyme responsible for the first step in succinoglycan biosynthesis. These results suggest that the level of symbiotic exopolysaccharide produced by a rhizobial species is one of the factors involved in optimizing the interaction with plant hosts.
- Subjects :
- Bacterial Proteins genetics
Bacterial Proteins metabolism
Gene Expression
Glucosyltransferases genetics
Glucosyltransferases metabolism
Medicago truncatula physiology
Metabolic Engineering
Sinorhizobium meliloti metabolism
Medicago truncatula microbiology
Polysaccharides, Bacterial biosynthesis
Sinorhizobium meliloti physiology
Symbiosis
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5530
- Volume :
- 194
- Issue :
- 16
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 22685282
- Full Text :
- https://doi.org/10.1128/JB.00751-12