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Article
Open AccessA consolidated analysis of the physiologic and molecular responses induced under acid stress in the legume-symbiont model-soil bacterium Sinorhizobium meliloti
Abiotic stresses in general and extracellular acidity in particular disturb and limit nitrogen-fixing symbioses between rhizobia and their host legumes. Except for valuable molecular-biological studies on diff...
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Article
A Rab-related small GTP binding protein is predominantly expressed in root nodules of Medicago sativa
Rab-related small GTP-binding proteins are known to be involved in the regulation of the vesicular transport system in eucaryotic cells. In this paper we report the isolation of the cDNA clone MS- rab11f from Med...
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Article
A microcosm study on the influence of pH and the host-plant on the soil persistence of two alfalfa-nodulating rhizobia with different saprophytic and symbiotic characteristics
The acid tolerance of Sinorhizobium meliloti in culture media and in soils is considered a useful criteria to select for strains with improved survival in agricultural acidic soils. Using a glass tube system wit...
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Article
Lipopolysaccharide biosynthesis in Xanthomonas campestris pv. campestris: a cluster of 15 genes is involved in the biosynthesis of the LPS O-antigen and the LPS core
As a result of mutational and DNA sequence analysis, a wxc gene cluster involved in the synthesis of the surface lipopolysaccharide (LPS) was identified in Xanthomonas campestris pv. campestris. This gene cluste...
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Article
Suppression of an elicitor-induced oxidative burst reaction in Nicotiana tabacum and Medicago sativa cell cultures by corticrocin but not by mycorradicin
The biological activities of mycorradicin, the major component of the yellow pigment formed in maize and other grasses upon colonization by arbuscular mycorrhizal fungi, and corticrocin from the ectomycorrhiza...
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Article
Transgenic tobacco plants that express an antisense construct derived from a Medicago sativa cDNA encoding a Rac-related small GTP-binding protein fail to develop necrotic lesions upon elicitor infiltration
Using an RT-PCR approach a rac-related cDNA clone, designated Ms-rac1, was isolated from Medicago sativa (alfalfa). Ms-rac1 encodes a putative protein of 197 amino acids, which is closely related to known Rac-re...
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Chapter
Suppression of Plant Defence Reactions in Alfalfa Cell Cultures by Sinorhizobium meliloti Surface Carbohydrates
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Chapter
The Usefulness of a Microcosms System with Acid Soil to Assess the Persistence of Acid Tolerant Alfalfa Nodulating Rhizobia
Acid soils represent a severe constraint for alfalfa crop in Argentina and Uruguay. The sustainable management of alfalfa pastures in these countries represents a main alternative to introduce N to the arable ...
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Chapter
Symbiotic Suppression of the Medicago sativa Plant Defence System by Rhizobium meliloti Oligosaccharides
The Rhizobium meliloti cell surface components, the exopolysaccharides (EPS I & EPS II) and the lipopolysaccharide (LPS), are known to be important in different stages of the establishment of the Medicago sativa ...
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Chapter
lpsB a Symbiotically Relevant Gene for R. meliloti is also Present and Functional in other Rhizobial Species
Rhizobial LPSs are among the bacterial surface compounds relevant for root infection in different symbiotic systems. In our laboratory we have characterized a Rhizobium meliloti lpsB mutant which was altered in c...
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Chapter
Characterization of an Acid Tolerant Rhizobium spp. Population-Low Diversity as a Consequence of Adaptation to Acid Soil?
The isolation of alfalfa-nodulating bacteria from acid soils in Argentina resulted in 12 distinct acid tolerant Rhizobium strains able to grow in synthetic media adjusted to pH 5.2. In this work we analysed the b...
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Article
Plant defence and delayed infection of alfalfa pseudonodules induced by an exopolysaccharide (EPS I)-deficient Rhizobium meliloti mutant
Mutants of the symbiotic soil bacterium Rhizobium meliloti that fail to synthesize the acidic exopolysaccharide EPS I were unable to induce infected root nodules on Medicago sativa L. (alfalfa). These strains, ho...
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Chapter
The Role of Rhizobium Meliloti Surface Polysaccharides in Nodule Development
The soil bacterium Rhizobium meliloti is well known for its symbiosis with Medicago sativa (alfalfa). It induces the development of so called root nodules which are infected by the microsymbiont. After colonizati...
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Chapter
The Role of the Rhizobium Meliloti Exopolysaccharides EPS I and EPS II in the Infection Process of Alfalfa Nodules
Rhizobium meliloti is able to produce two different exopolysaccharides, the succinoglucan EPS I and the alternative EPS II. R. meliloti mutants deficient in EPS I production are unable to form in...
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Chapter and Conference Paper
Infection Mutants of Rhizobium Meliloti are Altered in Acidic Exopolysaccharide Production
Rhizobium meliloti induces the formation of root nodules on its symbiotic partner alfalfa (Medicago sativa). The morphogenesis of the nodule is a complex interaction between the host plant and th...
