Role of Lectins in Plant-Microorganism Interactions

Bhuvaneswari, T. V.; Bauer, Wolfgang

doi:10.1104/pp.62.1.71

Cited by 72 publications

(15 citation statements)

References 35 publications

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“…6 and 7). The reduced nodulation efficiency on soybean confirms the earlier report by Law et al (19) and is consistent with the notion that interactions involving soybean lectin and B. japonicum receptor polysaccharide are important to establishment of the symbiosis (1,6,7,9,14,15,19,27). Since these mutants were just as efficient in nodule initiation as the parent on cowpea, the presence or absence of the soybean lectin binding polysaccharide was not important to cowpea nodulation, implying that nodule initiation on cowpea requires a different sort of signal substance from the cells.…”

Section: Resultssupporting

confidence: 81%

“…Since these mutants were just as efficient in nodule initiation as the parent on cowpea, the presence or absence of the soybean lectin binding polysaccharide was not important to cowpea nodulation, implying that nodule initiation on cowpea requires a different sort of signal substance from the cells. In this regard, it is of interest that B. japonicum strain 61A76 is deficient in synthesis of soybean lectin binding polysaccharide relative to stains 110, 123, and 138 (6,7) and is considerably less efficient in nodule initiation on soybean than these strains (6) but is just about as efficient in nodule initiation as 138 on cowpea (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

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Efficiency of Nodule Initiation in Cowpea and Soybean

Bhuvaneswari

Lesniak²,

Bauer³

1988

Plant Physiol.

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When serial dilutions of a suspension of Bradyrhizobium japonicum strain 138 were inoculated onto both soybean and cowpea roots, the formation of nodules in the initially susceptible region of the roots of both hosts was found to be linearly dependent on the log of the inoculum dosage until an optimum dosage was reached. Approximately 30-to 100-fold higher dosages were required to elicit half-maximal nodulation on cowpea than on soybean in the initially susceptible zone of the root. However, at optimal dosages, about six times as many nodules formed in this region on cowpea roots than on soybean roots. There was no appreciable difference in the apparent rate of nodule initiation on these two hosts nor in the number of inoculum bacteria in contact with the root. These results are consistent with the possibility that cowpea roots have a substantially higher threshold of response to symbiotic signals from the bacteria than do soybean roots. Storage ofB.japonicum cells in distilled water for several weeks did not affect their viability or efficiency of nodule initiation on soybean. However, the nodulation efficiency of these same cells on cowpea diminished markedly over a 2 week period. These differential effects of water storage indicate that at least some aspects of signal production by the bacteria during nodule initiation are different on the two hosts. Mutants of B. japonicum 138 defective in synthesis of soybean lectin binding polysaccharide were defective in their efficiency of nodule initiation on soybean but not on cowpea. These results also suggest that B. japonicum may produce different substances to initiate nodules on these two hosts.Rhizobium and Bradyrhizobium are soil bacteria able to symbiotically infect and nodulate a wide diversity of legumes, reducing atmospheric nitrogen in these nodules to ammonia for the plant in exchange for fixed carbon (1,12

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Section: Resultssupporting

confidence: 81%

Section: Resultsmentioning

confidence: 99%

Efficiency of Nodule Initiation in Cowpea and Soybean

Bhuvaneswari

Lesniak²,

Bauer³

1988

Plant Physiol.

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“…Recently, evidence has accumulated from several laboratories indicating that some form of bacterium-plant communication is important for the early symbiotic steps (3,4,7,8,13,14,17,18,29,37 (7), cause a phenotypic reversion in slow-to-nodulate B. japonicum HS111 (18), induce symbiosis-associated genes in Rhizobium fredii (29), and increase the competitiveness of some B. japonicum strains (3). Both positive and negative interactions of root-or seed-derived compounds (flavanones, flavanols, flavones, and isoflavones) have been shown with the common nodulation genes of Rhizobium meliloti (28, 30), Rhizobium trifolii (22), Rhizobium leguminosarum (49), and B. japonicum (Kosslak et al, in press).…”

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confidence: 99%

Two host-inducible genes of Rhizobium fredii and characterization of the inducing compound

et al. 1988

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Random transcription fusions with Mu dl(Kan lac) generated three mutants in Rhizobium fredii (strain USDA 201) which showed induction of I-galactosidase when grown in root exudate of the host plants Glycine max, Phaseolus vulgaris, and Vigna ungliculata. Two genes were isolated from a library of total plasmid DNA of one of the mutants, 3F1. These genes, present in tandem on a 4.2-kilobase Hindlll fragment, appear in one copy each on the symbiotic plasmid and do not hybridize to the Rhizobium meliloti common nodulation region. Regions homologous to both sequences were detected in EcoRI digests of genomic DNAs from B. japonicum USDA 110, USDA 122, and 61A76, but not in genomic DNA from R. trifolii, Rhizobium leguminosarum, or Rhizobium phaseoli. Mass spectrometry and nuclear magnetic resonance analysis indicated that the inducing compound has properties of 4',7-dihydroxyisoflavone, daidzein. These results suggest that, in addition to common nodulation genes, several other genes appear to be specifically induced by compounds in the root exudate of the host plants.The establishment of the Rhizobium-legume symbiosis requires that complex biochemical, physiological, and molecular changes occur in both partners. The most pronounced changes which occur during the formation of nitrogen-fixing nodules are the production of nodulins (10, 24), and the differentiation of rhizobia into nitrogen-fixing bacteroids (45). However, many subtle changes also occur during the early stages of the symbiotic process and likely involve the induction and repression of a large number of bacterial and plant genes (29; see references 32 and 46).While the early periods of the symbiosis have been shown to be important for nodulation and competition (23), most of our knowledge about plant-bacterium interactions has been limited to postinfection events (3). Recently, evidence has accumulated from several laboratories indicating that some form of bacterium-plant communication is important for the early symbiotic steps (3,4,7,8,13,14,17,18,29,37 (7), cause a phenotypic reversion in slow-to-nodulate B. japonicum HS111 (18), induce symbiosis-associated genes in Rhizobium fredii (29), and increase the competitiveness of some B. japonicum strains (3). Both positive and negative interactions of root-or seed-derived compounds (flavanones, flavanols, flavones, and isoflavones) have been shown with the common nodulation genes of Rhizobium meliloti (28, 30), Rhizobium trifolii (22), Rhizobium leguminosarum (49), and B. japonicum (Kosslak et al., in press). Using Mu dl(Kan lac) transcription fusions, we have identified three R. fredii USDA 201 insertion mutants which have symbiosis-related genes specifically induced by soybean root exudate and extract (29). Here we report on the isolation, cloning, and molecular analysis of two host plant-inducible operons in one of these mutants and the characterization of the inducing substance.MATERIALS AND METHODS Bacteria, plasmids, and growth conditions. R. fredii USDA 201 and the Mu dl(Kan lac) insertion mutants (3F...

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“…It is possible that these EPSs could vary in the location of their acetyl groups or in the amounts and/or location of (l-hydroxybutyric acid residues (18,19). In addition, changes in CPSs and EPSs (5) (3) (5) (5) (6) (3) (4) (2) (0) (2) (2) (2) (0) (2) (0) (0) have been detected as a function of growth phase (22), media (25), and the presence of root exudate (7). We are presently analyzing the extracellular material from several mutants which appear defective in EPS production (10, 12) but still nodulate their respective hosts.…”

Section: Discussionmentioning

confidence: 99%

A Structural Comparison of the Acidic Extracellular Polysaccharides from Rhizobium trifolii Mutants Affected in Root Hair Infection

Carlson

Hanley²,

Rolfe³

et al. 1986

Plant Physiol.

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The structures of the acidic extracellular polysaccharides (EPSs) from several R. trifolii mutants were compared by examining their compositions and their sugar linkages as determined by methylation analysis. These mutant strains were derived from the wild-type R. trifolii ANU843 and were unable to induce normal root hair curling (Hac-phenotype) or nodulation response (Nod-phenotype) in clover plants. These strains included several transposon Tn5-induced Nod-mutants, strain ANU871, which possesses a 40 to 50 kilobase deletion of the resident Sym plasmid, and strain ANU845 which is missing the Sym plasmid (pSym-). Strains ANU845(pSym-) containing either plasmid pRtl5O or pBRlAN were also used. The recombinant plasmid pRtlSO restores only root hair curling capacity to ANU845 while plasmid pBR1AN (an R. trifolii pSym) restores both root hair curling and nodulation capacity to this strain. Our composition and methylation results show that the EPSs from all these strains have the same glycosyl and pyruvyl linkages. Thus we suggest that neither the nod genes involved in root hair curling nor the entire pSym encodes for the arrangement of glycosyl or pyruvyl residues in these EPSs. Whether or not the nod genes dictate the location of acetyl or,6-hydroxybutyrate substituent groups remains to be determined.Rhizobia are gram-negative soil bacteria which form a nitrogen-fixing symbiotic relationship with legumes. This symbiotic relationship can be quite specific in which one species of Rhizobium will infect one genus of the Leguminosae. Early steps in Rhizobium-legume interaction involve the binding of rhizobia to the root hairs, root hair curling, and then infection thread formation (5, 9). Since the initial interaction between the symbiont Rhizobium and its host legume occurs at the surfaces of these two organisms, surface molecules are thought to play a role in determining some of these initial events. Specifically, the major surface polysaccharides of rhizobia are thought to be involved in their binding to the host root hair (5, 9). In addition, supernatants from rhizobia cultures are also known to deform and curl root hairs (29 (2,15,16,20), and R. phaseoli (13, 14) have been reported. These reports show that all the acidic EPSs consist of oligosaccharide repeating units. These structure studies reveal that: (a) strains of a single species such as R. phaseoli can produce EPSs with different structures (13,14), and (b) strains of different species, e.g. R. trifolii and R. meliloti (15) or R. trifolii, R. leguminosarum, and R. phaseoli ( 13,23) can produce EPSs with identical structures. This report compares the structures of the major acidic EPSs from several R. trifolii mutants which are altered in their ability to induce root hair curling and are defective in nodulation (Nod-).The mutants studied in this report are affected in the early infection event known as root hair curling. Table I gives a decription of these mutants. The genes responsible for this symbiotic event are located on a 5.3 kb BgI II fragment...

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Role of Lectins in Plant-Microorganism Interactions

Cited by 72 publications

References 35 publications

Efficiency of Nodule Initiation in Cowpea and Soybean

Efficiency of Nodule Initiation in Cowpea and Soybean

Two host-inducible genes of Rhizobium fredii and characterization of the inducing compound

A Structural Comparison of the Acidic Extracellular Polysaccharides from Rhizobium trifolii Mutants Affected in Root Hair Infection

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