Restriction of Host Range by the <i>sym2</i> Allele of Afghan Pea Is Nonspecific for the Type of Modification at the Reducing Terminus of Nodulation Signals

Ovtsyna, Alexandra O.; Geurts, René; Bisseling, Ton; Lugtenberg, Ben; Тихонович, И. А.; Spaink, Herman P.

doi:10.1094/mpmi.1998.11.5.418

Cited by 29 publications

(19 citation statements)

References 31 publications

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“…Tetrameric Nod factors of S. meliloti were more stable against degradation by root hydrolytic enzymes when they carried a sulfate ester at the reducingterminal residue (21). Recently, Ovtsyna et al (52) proposed that the 6-O-acetyl group at the reducing-terminal residue of Nod factors of R. leguminosarum bv. viciae may play a role in increasing the stability toward Afghan pea chitinases, but not in a specific receptor-ligand interaction, because a fucosyl group could functionally replace the structurally different 6-Oacetyl group.…”

Section: Discussionmentioning

confidence: 99%

Nod Factor Requirements for Efficient Stem and Root Nodulation of the Tropical Legume Sesbania rostrata

D’Haeze¹,

Mergaert²,

Promé³

et al. 2000

Journal of Biological Chemistry

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Azorhizobium caulinodans ORS571 synthesizes mainly pentameric Nod factors with a household fatty acid, an N-methyl, and a 6-O-carbamoyl group at the nonreducing-terminal residue and with a D-arabinosyl, an L-fucosyl group, or both at the reducing-terminal residue. Nodulation on Sesbania rostrata was carried out with a set of bacterial mutants that produce well characterized Nod factor populations. Purified Nod factors were tested for their capacity to induce root hair formation and for their stability in an in vitro degradation assay with extracts of uninfected adventitious rootlets. The glycosylations increased synergistically the nodulation efficiency and the capacity to induce root hairs, and they protected the Nod factor against degradation. The D-arabinosyl group was more important than the L-fucosyl group for nodulation efficiency. Replacement of the 6-O-L-fucosyl group by a 6-O-sulfate ester did not affect Nod factor stability, but reduced nodulation efficiency, indicating that the L-fucosyl group may play a role in recognition. The 6-O-carbamoyl group contributes to nodulation efficiency, biological activity, and protection, but could be replaced by a 6-O-acetyl group for root nodulation. The results demonstrate that none of the studied substitutions is strictly required for triggering normal nodule formation. However, the nodulation efficiency was greatly determined by the synergistic presence of substitutions. Within the range tested, fluctuations of Nod factor amounts had little impact on the symbiotic phenotype.

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Section: Discussionmentioning

confidence: 99%

Nod Factor Requirements for Efficient Stem and Root Nodulation of the Tropical Legume Sesbania rostrata

D’Haeze¹,

Mergaert²,

Promé³

et al. 2000

Journal of Biological Chemistry

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“…Several cultivar-specific interactions have been studied where the host range of nodulation within a species of plant is specifically limited. In the Afghanistan cultivar of pea, specific non-nodulation responses occur that are determined by the absence of acetylation at the nonreducing end of the LCOs made by non-nodulating strains and by a single gene trait in the plant, sym-2 [6]. This non-nodulation response is known to be governed by both host and bacterial determinants and is somewhat similar to cultivar-based resistance well recognised in plant-pathogen interactions [4,5].…”

Section: Introductionmentioning

confidence: 89%

Proteome analysis of cultivar-specific interactions betweenRhizobium leguminosarum biovartrifolii and subterranean clover cultivar Woogenellup

Morris

Djordjevic

2001

Electrophoresis

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Proteome analysis was used to identify proteins that are involved in the early stages of nodulation between the subterranean clover cultivar Woogenellup and the Rhizobium leguminosarum bv. trifolii strains ANU843 and ANU794. Strain ANU843 induces nitrogen-fixing nodules whereas strain ANU794 forms aberrant nodules on the roots of cv. Woogenellup that fail to develop beyond an early stage. Our aim was to identify proteins that might be involved in the early stages of nodulation over a 48 h period and to identify proteins that are differentially displayed during the interactions between the host and the two microbes. Proteome maps from control Woogenellup roots and inoculated roots were generated and compared at 24 and 48 h post inoculation. Over 1500 spots were resolved on all gels. Of the 16 protein spots that were differentally displayed or developmentally regulated, 10 were assigned putative identities. These included an alpha-fucosidase, several ethylene-induced proteins, a Cu/Zn superoxide dismutase, a hypothetical 16.5 kDa protein, tubulin alpha-chain, chaperonin 21 precursor and triosephosphate isomerase. Of the 22 constitutively expressed proteins spots examined, eight spots were assigned putative protein homologies through N-terminal sequencing and included several pathogenesis and stress-related proteins. The result may suggest that ethylene levels are upregulated during the early stages of infection but that this does not result in the induction of common pathogenesis-related proteins. The specific induction of alpha-fucosidase by ANU794 may be important in the nodulation failure phenotype of strain ANU794.

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“…In R. leguminosarum bv. viciae however, a fucosyl group added by NodZ can functionally replace the missing acetyl group in a nodX mutant (189). Although NodL is responsible for acetylation of C-6 of the nonreducing terminus in R. meliloti Nod factors (2), R. meliloti nodL mutants are impaired in their ability to elicit infection thread formation on M. sativa but form nodules with only a moderate delay (96).…”

Section: Nod Enzymes and Nod Factor Synthesismentioning

confidence: 99%

Molecular Basis of Symbiotic Promiscuity

Perret

Staehelin

Broughton

2000

Microbiol Mol Biol Rev

877

630

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SUMMARY Eukaryotes often form symbioses with microorganisms. Among these, associations between plants and nitrogen-fixing bacteria are responsible for the nitrogen input into various ecological niches. Plants of many different families have evolved the capacity to develop root or stem nodules with diverse genera of soil bacteria. Of these, symbioses between legumes and rhizobia (Azorhizobium, Bradyrhizobium, Mesorhizobium, and Rhizobium) are the most important from an agricultural perspective. Nitrogen-fixing nodules arise when symbiotic rhizobia penetrate their hosts in a strictly controlled and coordinated manner. Molecular codes are exchanged between the symbionts in the rhizosphere to select compatible rhizobia from pathogens. Entry into the plant is restricted to bacteria that have the “keys” to a succession of legume “doors”. Some symbionts intimately associate with many different partners (and are thus promiscuous), while others are more selective and have a narrow host range. For historical reasons, narrow host range has been more intensively investigated than promiscuity. In our view, this has given a false impression of specificity in legume-Rhizobium associations. Rather, we suggest that restricted host ranges are limited to specific niches and represent specialization of widespread and more ancestral promiscuous symbioses. Here we analyze the molecular mechanisms governing symbiotic promiscuity in rhizobia and show that it is controlled by a number of molecular keys.

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Restriction of Host Range by the sym2 Allele of Afghan Pea Is Nonspecific for the Type of Modification at the Reducing Terminus of Nodulation Signals

Cited by 29 publications

References 31 publications

Nod Factor Requirements for Efficient Stem and Root Nodulation of the Tropical Legume Sesbania rostrata

Nod Factor Requirements for Efficient Stem and Root Nodulation of the Tropical Legume Sesbania rostrata

Proteome analysis of cultivar-specific interactions betweenRhizobium leguminosarum biovartrifolii and subterranean clover cultivar Woogenellup

Molecular Basis of Symbiotic Promiscuity

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