Effects of nutritional and environmental conditions on Sinorhizobium meliloti biofilm formation

Rinaudi, Luciana Veronica; Fujishige, Nancy A.; Hirsch, Ann M.; Banchio, Erika; Zorreguieta, Ángeles; Giordano, Walter

doi:10.1016/j.resmic.2006.06.002

Cited by 110 publications

(94 citation statements)

References 51 publications

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“…It was found that concentrations of phosphate, calcium, and sucrose influenced biofilm formation in S. meliloti, and these effects were positively correlated with amounts of EPS synthesized under these conditions (Rinaudi et al 2006). In contrast, pH and extreme temperature negatively influenced this process.…”

Section: Discussionmentioning

confidence: 96%

Production of exopolysaccharide by Rhizobium leguminosarum bv. trifolii and its role in bacterial attachment and surface properties

et al. 2014

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Background and aims The acidic exopolysaccharide (EPS) produced by Rhizobium leguminosarum bv. trifolii is required for the establishment of effective symbiosis with compatible host plants (Trifolium spp.). In the rhizobium-legume interaction, early stages of root infection and nodule development have been well studied from a genetic standpoint. However, factors important for colonization of several surfaces by rhizobia, including soil particles and roots, have not yet been thoroughly investigated. The aim of this study was establishing of environmental factors affecting production of EPS by R. leguminosarum bv. trifolii strain 24.2 and the role of this polysaccharide in bacterial surface properties and attachment ability. Methods Besides the wild-type strain, its derivatives differing in the level of EPS produced were used to these analyses. The ability of attachment to abiotic and biotic surfaces of these strains were established using CFU counting experiments. Three-dimensional structure and other parameters of biofilms formed were characterized in confocal laser scanning microscopy. Electrokinetic (zeta) potential of rhizobial cells were determined using Laser Doppler Velocimetry. Results It was evidenced that the ability of R. leguminosarum bv. trifolii to produce EPS significantly affected bacterial attachment and biofilm formation on both abiotic and biotic surfaces. In addition, the presence of this polysaccharide influenced the zeta potential of rhizobial cells. Mutant strains having a mutation in genes involved in EPS synthesis were significantly impaired in attachment, whereas strains overproducing this polysaccharide showed higher adhesion efficiency to all of the tested materials. EPS facilitated attachment of bacterial cells to the tested surfaces most probably due to hydrophobic interactions and heterogeneity of the envelope surface. Conclusions EPS produced by R. leguminosarum bv. trifolii plays a significant role in attachment and biofilm formation to both abiotic and biotic surfaces as well as bacterial surface properties.

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Section: Discussionmentioning

confidence: 96%

Production of exopolysaccharide by Rhizobium leguminosarum bv. trifolii and its role in bacterial attachment and surface properties

et al. 2014

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“…It is interesting, however, that similar phenotypes have been linked to biofilm production (22,26,73). Biofilms have recently been shown to occur in Rhizobia (23,62,65). In Rhizobium leguminosarum, the PrsD-PrsE secretion system was shown to be involved in biofilm production (65).…”

Section: Discussionmentioning

confidence: 99%

The ExpR/Sin Quorum-Sensing System Controls Succinoglycan Production in Sinorhizobium meliloti

et al. 2007

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Sinorhizobium meliloti is a gram-negative soil bacterium capable of forming a symbiotic nitrogen-fixing relationship with its plant host, Medicago sativa. Various bacterially produced factors are essential for successful nodulation. For example, at least one of two exopolysaccharides produced by S. meliloti (succinoglycan or EPS II) is required for nodule invasion. Both of these polymers are produced in high-and low-molecular-weight (HMW and LMW, respectively) fractions; however, only the LMW forms of either succinoglycan or EPS II are active in nodule invasion. The production of LMW succinoglycan can be generated by direct synthesis or through the depolymerization of HMW products by the action of two specific endoglycanases, ExsH and ExoK. Here, we show that the ExpR/Sin quorum-sensing system in S. meliloti is involved in the regulation of genes responsible for succinoglycan biosynthesis as well as in the production of LMW succinoglycan. Therefore, quorum sensing, which has been shown to regulate the production of EPS II, also plays an important role in succinoglycan biosynthesis.

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“…Coordination of many cellular processes, including exopolysaccharide production, motility, stress adaptation, and biofilm production, must occur in order for rhizobia to persist in their soil and plant settings (5,33,50,59). In the gramnegative soil bacterium Sinorhizobium meliloti, the production of exopolysaccharides is particularly crucial because it provides the capacity to form an association with Medicago sativa (alfalfa) (27,33).…”

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confidence: 99%

The Novel Genes emmABC Are Associated with Exopolysaccharide Production, Motility, Stress Adaptation, and Symbiosis in Sinorhizobium meliloti

Morris

Gonzalez

2009

J Bacteriol

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The nitrogen-fixing symbiont Sinorhizobium meliloti senses and responds to constantly changing environmental conditions as it makes its way through the soil in search of its leguminous plant host, Medicago sativa (alfalfa). As a result, this bacterium regulates various aspects of its physiology in order to respond appropriately to stress, starvation, and competition. For example, exopolysaccharide production, which has been shown to play an important role in the ability of S. meliloti to successfully invade its host, also helps the bacterium withstand osmotic changes and other environmental stresses. In an effort to further elucidate the intricate regulation of this important cell component, we set out to identify genetic factors that may affect its production. Here we characterize novel genes that encode a small protein (EmmA) and a putative two-component system (EmmB-EmmC). A mutation in any of these genes leads to increased production of the symbiotically important exopolysaccharide succinoglycan. In addition, emm mutants display membrane-associated defects, are nonmotile, and are unable to form an optimal symbiosis with alfalfa, suggesting that these novel genes may play a greater role in the overall fitness of S. meliloti both during the free-living stage and in its association with its host.

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Effects of nutritional and environmental conditions on Sinorhizobium meliloti biofilm formation

Cited by 110 publications

References 51 publications

Production of exopolysaccharide by Rhizobium leguminosarum bv. trifolii and its role in bacterial attachment and surface properties

Production of exopolysaccharide by Rhizobium leguminosarum bv. trifolii and its role in bacterial attachment and surface properties

The ExpR/Sin Quorum-Sensing System Controls Succinoglycan Production in Sinorhizobium meliloti

The Novel Genes emmABC Are Associated with Exopolysaccharide Production, Motility, Stress Adaptation, and Symbiosis in Sinorhizobium meliloti

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