Disturbed gene expression and bacteroid development in Trifolium pratense root nodules induced by a Tn5 mutant of Rhizobium leguminosarum bv. trifolii defective in exopolysaccharide synthesis

Bialek, U.; Skorupska, Anna; Yang, Wei‐Cai; Bisseling, Ton; Lammeren, A.A.M. van

doi:10.1007/bf00239955

Cited by 11 publications

(9 citation statements)

References 20 publications

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“…Several experimental data evidenced that EPS production by rhizobia that nodulate host legumes forming indeterminate-type nodules, such as Vicia, Medicago, Pisum or Trifolium , is required for tight root hair curling, proper infection thread formation, bacteria release, bacteroid development and the effective nodulation [ 11 , 83 , 93 , 130 , 131 ]. Two types of experiments aimed at uncovering the specific role of EPS in symbiosis.…”

Section: Reviewmentioning

confidence: 99%

Rhizobial exopolysaccharides: genetic control and symbiotic functions

et al. 2006

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Specific complex interactions between soil bacteria belonging to Rhizobium, Sinorhizobium, Mesorhizobium, Phylorhizobium, Bradyrhizobium and Azorhizobium commonly known as rhizobia, and their host leguminous plants result in development of root nodules. Nodules are new organs that consist mainly of plant cells infected with bacteroids that provide the host plant with fixed nitrogen. Proper nodule development requires the synthesis and perception of signal molecules such as lipochitooligosaccharides, called Nod factors that are important for induction of nodule development. Bacterial surface polysaccharides are also crucial for establishment of successful symbiosis with legumes. Sugar polymers of rhizobia are composed of a number of different polysaccharides, such as lipopolysaccharides (LPS), capsular polysaccharides (CPS or K-antigens), neutral β-1, 2-glucans and acidic extracellular polysaccharides (EPS). Despite extensive research, the molecular function of the surface polysaccharides in symbiosis remains unclear.This review focuses on exopolysaccharides that are especially important for the invasion that leads to formation of indetermined (with persistent meristem) type of nodules on legumes such as clover, vetch, peas or alfalfa. The significance of EPS synthesis in symbiotic interactions of Rhizobium leguminosarum with clover is especially noticed. Accumulating data suggest that exopolysaccharides may be involved in invasion and nodule development, bacterial release from infection threads, bacteroid development, suppression of plant defense response and protection against plant antimicrobial compounds. Rhizobial exopolysaccharides are species-specific heteropolysaccharide polymers composed of common sugars that are substituted with non-carbohydrate residues. Synthesis of repeating units of exopolysaccharide, their modification, polymerization and export to the cell surface is controlled by clusters of genes, named exo/ exs, exp or pss that are localized on rhizobial megaplasmids or chromosome. The function of these genes was identified by isolation and characterization of several mutants disabled in exopolysaccharide synthesis. The effect of exopolysaccharide deficiency on nodule development has been extensively studied. Production of exopolysaccharides is influenced by a complex network of environmental factors such as phosphate, nitrogen or sulphur. There is a strong suggestion that production of a variety of symbiotically active polysaccharides may allow rhizobial strains to adapt to changing environmental conditions and interact efficiently with legumes.

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Section: Reviewmentioning

confidence: 99%

Rhizobial exopolysaccharides: genetic control and symbiotic functions

et al. 2006

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“…Ulka. Seeds were surface-sterilized, germinated, and grown as described earlier (Skorupska et al 1995). After 5 weeks, the plants were checked for growth, nodule development, and nodule occupancy.…”

Section: Plant Testsmentioning

confidence: 99%

“…Mutants of R. leguminosarum bv. trifolii deficient in EPS production form partially infected nodules that do not fix nitrogen (Białek et al 1995;Chen et al 1985;Rolfe et al 1996;Skorupska et al 1995). EPS is a polymer of repeating units that consists of five glucoses, two glucuronic acids, and one galactose with acetyl, pyruvyl, and hydroxybutanoyl modifications (Philip-Hollingsworth et al 1989).…”

Section: Introductionmentioning

confidence: 98%

The Rhizobium leguminosarum bv. trifolii pssB gene product is an inositol monophosphatase that influences exopolysaccharide synthesis

Janczarek

Skorupska

2001

Archives of Microbiology

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The pssB gene of Rhizobium leguminosarum bv. trifolii encodes a protein of 284 amino acids with sequence similarity to eukaryotic inositol monophosphatases. The gene was cloned and overexpressed in Escherichia coli. The purified gene product of pssB showed inositol monophosphatase activity with a Km of 0.23 mM, and a Vmax of 3.27 mumol Pi min-1 (mg protein)-1. Its substrate specificity, Mg+2 requirement, Li+ inhibition, and subunit association (dimerization) were studied and compared to those of other inositol monophosphatases. Western immunoblotting with anti-PssB antibodies showed the presence of PssB in R. leguminosarum bv. trifolii strain TA1 and lack of this protein in the pssB mutant strain Rt12A. The presence of PssB protein in R. leguminosarum bv. trifolii TA1 was correlated with phosphatase activity with myo-inositol 1-phosphate as a substrate. Evidence for a regulatory function of PssB protein in exopolysaccharide (EPS) synthesis is presented. The mutation in pssB caused EPS overproduction, and introduction of pssB into the wild-type TA1 strain reduced EPS synthesis. The changes in the level of EPS production were correlated with a non-nitrogen-fixing phenotype of rhizobia.

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“…This is particularly the case for the formation of indeterminate nodules, although there are few examples for EPS mutants inducing effective indeterminate nodules, as was reported for EPS mutants of astragali rhizobia on Astragalus sinicus (Chen et al, 1996) and for some EPS mutants of Rhizobium sp. strain TAL1l45 do not nodulate their host plants, which form indeterminate nodules or induce nodules devoid of bacteria due to the formation of abortive infection threads (Chakravorty et al, 1982;Borthakur et aI., 1986;Finan et al, 1985;Leigh et al, 1985;Diebold and Noel 1989;Bialek et al, 1995;Skropuska et al, 1995;Parveen et aJ., 1996;. EPS deficient mutants of R. leguminosarum bv.…”

Section: Ivb Role Of Exopol Ysaccha-rides In Root Nodule Symbiosismentioning

confidence: 99%

“…Definitions of parasitism or mutualism depend on our knowledge of the different types of interactions between the associated organisms. In Trifolium pratense absence of EPS synthesis triggered plant defense responses after release from the infection thread (Skorupska et al, 1995). Actions, which are synergistic in one direction mostly, are antagonistic in the other way.…”

Section: Iic Parasitic ¢ Mutualistic Associationmentioning

confidence: 99%

The Rhizobiaceae

1998

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Disturbed gene expression and bacteroid development in Trifolium pratense root nodules induced by a Tn5 mutant of Rhizobium leguminosarum bv. trifolii defective in exopolysaccharide synthesis

Cited by 11 publications

References 20 publications

Rhizobial exopolysaccharides: genetic control and symbiotic functions

Rhizobial exopolysaccharides: genetic control and symbiotic functions

The Rhizobium leguminosarum bv. trifolii pssB gene product is an inositol monophosphatase that influences exopolysaccharide synthesis

The Rhizobiaceae

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