Characterization of a<i>Rhizobium meliloti</i>Proline Dehydrogenase Mutant Altered in Nodulation Efficiency and Competitiveness on Alfalfa Roots

Jiménez‐Zurdo, José I.; Dillewijn, Pieter van; Soto, Marı́a José; Felipe, Ma Rosario de; Olivares, J.; Toro, Nicolás

doi:10.1094/mpmi-8-0492

Cited by 55 publications

(37 citation statements)

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“…It was previously shown that mutations in genes responsible for the catabolism of carbon sources, such as rhamnose and myoinositol, and other used nutrients, such as mimosine, are correlated with a decreased ability to compete for nodule occupancy (47)(48)(49)(50). Therefore, we investigated if the presence of the oxalate catabolic pathway could represent a competitive advantage for nodulation occupancy on all host plants.…”

Section: Resultsmentioning

confidence: 99%

A Link between Arabinose Utilization and Oxalotrophy in Bradyrhizobium japonicum

Koch

Delmotte

Ahrens

et al. 2014

Appl Environ Microbiol

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cRhizobia have a versatile catabolism that allows them to compete successfully with other microorganisms for nutrients in the soil and in the rhizosphere of their respective host plants. In this study, Bradyrhizobium japonicum USDA 110 was found to be able to utilize oxalate as the sole carbon source. A proteome analysis of cells grown in minimal medium containing arabinose suggested that oxalate oxidation extends the arabinose degradation branch via glycolaldehyde. A mutant of the key pathway genes oxc (for oxalyl-coenzyme A decarboxylase) and frc (for formyl-coenzyme A transferase) was constructed and shown to be (i) impaired in growth on arabinose and (ii) unable to grow on oxalate. Oxalate was detected in roots and, at elevated levels, in root nodules of four different B. japonicum host plants. Mixed-inoculation experiments with wild-type and oxc-frc mutant cells revealed that oxalotrophy might be a beneficial trait of B. japonicum at some stage during legume root nodule colonization.

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Section: Resultsmentioning

confidence: 99%

A Link between Arabinose Utilization and Oxalotrophy in Bradyrhizobium japonicum

Koch

Delmotte

Ahrens

et al. 2014

Appl Environ Microbiol

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“…Previous studies (11) have suggested that the competitiveness of S. meliloti strains could be increased by increasing expression of the putA gene. To test this hypothesis, we inserted a promoter that would ensure high basal putA gene expression.…”

Section: Resultsmentioning

confidence: 96%

“…The putA gene, which encodes proline dehydrogenase, the enzyme catalyzing the oxidation of proline to glutamate, is one of the genetic loci thought to be involved in this symbiotic property. The ability of a PutA Ϫ mutant to colonize the root surface was found to be impaired, as were nodulation efficiency and competitiveness (11,12). The root exudates of the host plant of S. meliloti, alfalfa (Medicago sativa L.), contain proline and compounds such as betaines and stachydrine that release proline upon degradation (20).…”

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confidence: 99%

“…Complementation of the PutA Ϫ mutant with a cosmid containing the wild-type putA gene did more than merely restore the competitiveness of the mutant to wild-type levels; it actually rendered the complemented mutant more competitive than the wild type (11). This suggested that manipulation of the expression of this gene could be used to improve the competitiveness of S. meliloti strains in field conditions.…”

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confidence: 99%

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Construction and Environmental Release of a Sinorhizobium meliloti Strain Genetically Modified To Be More Competitive for Alfalfa Nodulation

Dillewijn

Soto

Villadas

et al. 2001

Appl Environ Microbiol

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؊ mutant strain, that proline dehydrogenase activity is required for colonization and therefore for the nodulation efficiency and competitiveness of S. meliloti on alfalfa roots (J. I. Jiménez-Zurdo, P. van Dillewijn, M. J. Soto, M. R. de Felipe, J. Olivares, and N. Toro, Mol. Plant-Microbe Interact. 8:492-498, 1995). In this work, we investigated whether the putA gene could be used as a means of increasing the competitiveness of S. meliloti strains. We produced a construct in which a constitutive promoter was placed 190 nucleotides upstream from the start codon of the putA gene. This resulted in an increase in the basal expression of this gene, with this increase being even greater in the presence of the substrate proline. We found that the presence of multicopy plasmids containing this putA gene construct increased the competitiveness of S. meliloti in microcosm experiments in nonsterile soil planted with alfalfa plants subjected to drought stress only during the first month. We investigated whether this construct also increased the competitiveness of S. meliloti strains under agricultural conditions by using it as the inoculum in a contained field experiment at León, Spain. We found that the frequency of nodule occupancy was higher with inoculum containing the modified putA gene for samples that were analyzed after 34 days but not for samples that were analyzed later.

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“…The partial-growth as opposed to the no-growth phenotype of the hypH and hypO mutants can be attributed to the presence of alternate enzyme activities. HypO is (20,49,64,65,67). Abbreviations: Pyr5C, ⌬ 1 -pyrroline-5-carboxylate; Pyr2C, ⌬ 1 -pyrroline-2-carboxylate; ␥-glutamyl-5-P, ␥-glutamyl-5-phosphate; Pi, phosphate.…”

Section: Discussionmentioning

confidence: 99%

l -Hydroxyproline and d -Proline Catabolism in Sinorhizobium meliloti

et al. 2016

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Sinorhizobium meliloti IMPORTANCEHydroxyproline is abundant in proteins in animal and plant tissues and serves as a carbon and a nitrogen source for bacteria in diverse environments, including the rhizosphere, compost, and the mammalian gut. While the main biochemical features of bacterial hydroxyproline catabolism were elucidated in the 1960s, the genetic and molecular details have only recently been determined. Elucidating the genetics of hydroxyproline catabolism will aid in the annotation of these genes in other genomes and metagenomic libraries. This will facilitate an improved understanding of the importance of this pathway and may assist in determining the prevalence of hydroxyproline in a particular environment.4-Hydroxyproline and 3-hydroxyproline in animal and plant proteins are formed through the posttranslational modification of proline residues by the enzyme proline hydroxylase. In some bacteria, hydroxyproline is synthesized from free L-proline, where it is employed in the synthesis of secondary metabolites (1, 2). 4-Hydroxyproline has two chiral carbon atoms, and of its four isomeric forms, trans-4-hydroxy-L-proline (trans-4-L-Hyp) and cis-4-hydroxy-D-proline (cis-4-D-Hyp) appear to be the two most common isomers. trans-4-

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Characterization of aRhizobium melilotiProline Dehydrogenase Mutant Altered in Nodulation Efficiency and Competitiveness on Alfalfa Roots

Cited by 55 publications

References 0 publications

A Link between Arabinose Utilization and Oxalotrophy in Bradyrhizobium japonicum

A Link between Arabinose Utilization and Oxalotrophy in Bradyrhizobium japonicum

Construction and Environmental Release of a Sinorhizobium meliloti Strain Genetically Modified To Be More Competitive for Alfalfa Nodulation

l -Hydroxyproline and d -Proline Catabolism in Sinorhizobium meliloti

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