Root Lectins and Rhizobia (original) (raw)
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REVIEW Plant lectins: the ties that bind in root symbiosis and plant defense
Lectins are a diverse group of carbohydratebinding proteins that are found within and associated with organisms from all kingdoms of life. Several diVerent classes of plant lectins serve a diverse array of functions. The most prominent of these include participation in plant defense against predators and pathogens and involvement in symbiotic interactions between host plants and symbiotic microbes, including mycorrhizal fungi and nitrogen-Wxing rhizobia. Extensive biological, biochemical, and molecular studies have shed light on the functions of plant lectins, and a plethora of uncharacterized lectin genes are being revealed at the genomic scale, suggesting unexplored and novel diversity in plant lectin structure and function. Integration of the results from these diVerent types of research is beginning to yield a more detailed understanding of the function of lectins in symbiosis, defense, and plant biology in general.
Plant lectins: the ties that bind in root symbiosis and plant defense
Molecular Genetics and Genomics, 2009
Lectins are a diverse group of carbohydratebinding proteins that are found within and associated with organisms from all kingdoms of life. Several diVerent classes of plant lectins serve a diverse array of functions. The most prominent of these include participation in plant defense against predators and pathogens and involvement in symbiotic interactions between host plants and symbiotic microbes, including mycorrhizal fungi and nitrogen-Wxing rhizobia. Extensive biological, biochemical, and molecular studies have shed light on the functions of plant lectins, and a plethora of uncharacterized lectin genes are being revealed at the genomic scale, suggesting unexplored and novel diversity in plant lectin structure and function. Integration of the results from these diVerent types of research is beginning to yield a more detailed understanding of the function of lectins in symbiosis, defense, and plant biology in general.
Effect of Leguminous Lectins on the Growth of Rhizobium tropici CIAT899
Molecules, 2013
Rhizobium tropici is a Gram-negative bacterium that induces nodules and fixed atmospheric nitrogen in symbiotic association with Phaseolus vulgaris (common bean) and some other leguminous species. Lectins are proteins that specifically bind to carbohydrates and, consequently, modulate different biological functions. In this study, the D-glucose/ D-mannose-binding lectins (from seeds of Dioclea megacarpa, D. rostrata and D. violacea) and D-galactose-binding lectins (from seeds of Bauhinia variegata, Erythina velutina and Vatairea macrocarpa) were purified using chromatographic techniques and evaluated for
Plant Physiology, 2001
Transgenic alfalfa (Medicago sativa L. cv Regen) roots carrying genes encoding soybean lectin or pea (Pisum sativum) seed lectin (PSL) were inoculated with Bradyrhizobium japonicum or Rhizobium leguminosarum bv viciae, respectively, and their responses were compared with those of comparably inoculated control plants. We found that nodule-like structures formed on alfalfa roots only when the rhizobial strains produced Nod factor from the alfalfa-nodulating strain, Sinorhizobium meliloti. Uninfected nodule-like structures developed on the soybean lectin-transgenic plant roots at very low inoculum concentrations, but bona fide infection threads were not detected even when B. japonicum produced the appropriate S. meliloti Nod factor. In contrast, the PSL-transgenic plants were not only well nodulated but also exhibited infection thread formation in response to R. leguminosarum bv viciae, but only when the bacteria expressed the complete set of S. meliloti nod genes. A few nodules from the PSL-transgenic plant roots were even found to be colonized by R. leguminosarum bv viciae expressing S. meliloti nod genes, but the plants were yellow and senescent, indicating that nitrogen fixation did not take place. Exopolysaccharide appears to be absolutely required for both nodule development and infection thread formation because neither occurred in PSL-transgenic plant roots following inoculation with an Exo Ϫ R. leguminosarum bv viciae strain that produced S. meliloti Nod factor. to A.M.H.) and by the D. Collen Research Foundation, K.U. Leuven, Belgium (to P.v.R.). LITERATURE CITED Becker A, Pü hler A (1998) Production of exopolysaccharides. In HP Spaink, A Kondorosi, PJJ Hooykaas, eds, The Rhizobiaceae: Molecular Biology of Model Plant-Associated Bacteria. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp 97-118 Beringer JE (1974) R-factor transfer in Rhizobium leguminosarum. J Gen Microbiol 120: 421-429 Bingham ET (1991) Registration of alfalfa hybrid Regen-SY germplasm for tissue culture and transformation research. Crop Sci 31: 1098 Bohlool BB, Schmidt EL (1974) Lectins: a possible basis for specificity in the Rhizobium-legume root nodule symbiosis. Science 185: 269-271 Borthakur D, Barber CE, Lamb JW, Daniels MJ, Downie JA, Johnston AWB (1986) A mutation that blocks exopolysaccharide synthesis prevents nodulation of peas by Rhizobium leguminosarum but not of beans by R. phaseoli and is corrected by cloned DNA from Rhizobium or the phytopathogen Xanthomonas. Mol Gen Genet 203: 320-323 Borthakur D, Barker RF, Latchford JW, Rossen L, Johnston AWB (1988) Analysis of pss genes in Rhizobium leguminosarum required for exopolysaccharide synthesis and nodulation of peas: their primary structure and their interaction with psi and other nodulation genes. Mol Gen Genet 213: 155-162 Cárdenas L, Vidali L, Dominguez J, Perez H, Sánchez F, Hepler PK, Quinto C (1998) Rearrangement of actin microfilaments in plant root hairs responding to Rhizobium etli nodulation signals. Plant Physiol 116: 871-877 Carlson RW, Sanjuan J, Ramadas Bhat U, Glushka J, Spaink JP, Wijfjes AHM, van Brussel AAN, Stokkermans TJW, Peters NK, Stacey G (1993) The structures and biological activities of the lipo-oligosaccharide nodulation signals produced by type I and II strains of Bradyrhizobium japonicum.
Legume Lectins : A Promising Candidate for Confronting a Plethora of Biotic Stresses
Legume lectins are largest and best characterized families of plant lectins. These are homologous carbohydrate binding proteins that are found mainly in the seeds of legume plants. Despite their strong similarity on the level of their amino acid sequences and tertiary structures, their carbohydrate specificities and quaternary structures vary widely. In this review we will focus on the structural features of legume lectins and their complexes with carbohydrates. Legume lectins comprise a structurally related, Ca/Mn-dependent, widespread, abundant and well characterized lectin family when compared to the large number of lectins from other sources described in the literature. They have at least one non-catalytic domain that binds reversibly to specific monosaccharides or oligosaccharides. Legume lectins have diverse of activity such as antimicrobial, insecticidal activities, antitumor, immune-modulatory, and HIV-1 reverse transcriptase inhibitory, which may find applications in many therapeutic areas.
Canadian Journal of Microbiology, 1978
The binding of purified, ferritin-labeled soybean seed lectin to the cell surfaces of Rhizobium japonicum 31 lb 138 has been examined by whole mount, thin section, and freeze-etch electron microscopy. The ferritin-labeled lectin binds in a biochemically specific manner to the capsular material of this bacterium. The lectin does not bind to the outer membranes of the cells or to flagella. Labeled lectin binds to sites throughout the capsular structure, although the density of labeling is somewhat greater on the outer surface of the capsule. Some cells appear to be partially encapsulated. Preservation of the capsular material proved difficult, and methods for retaining most of the capsular material were developed.
Artificial colonization of non-symbiotic plants roots with the use of lectins
Rhizobia have the ability to increase growth of non-legume plants due to the production of phytohormones and protection of plant from diseases and pathogens. However, the practical use of these beneficial bacteria sometimes fails because of their inability to effectively colonize rhizoplane and rhizosphere of inoculated plants. We chose the legume lectins as a factor that allows plants to form associative symbiosis with rhizobia. To test the fact that transgenic tobacco, tomato and rape roots with pea lectin gene may affect specific interaction with rhizobia, transgenic roots have been artificially inoculated by fluorescentlylabeled pea rhizobia R. leguminosarum and east galega rhizobia Rhizobium galega. Microscopic and microbiological tests have shown that the number of adhered R. leguminosarum onto tobacco, rape and tomato roots which transformed with pea lectin gene is higher in comparison with the control, but no such effect through inoculation of these plants with R. galegae has been found. This confirms the interaction of R. leguminosarum with pea lectin at the surface of transformed roots. Undoubtedly, the improvement of recognition and attachment processes by using lectins can lead to the achievement of a stable associative relationship between non-symbiotic plants and rhizobia.
Interaction of pea (Pisum sativum L.) lectins with rhizobial strains
Microbiological Research, 2001
Lectins from two varieties (PG-3 and LFP-48) of pea have been purified by affinity chromatography on Sephadex G-50. The specific activity increased by 23 and 25 folds, respectively. These lectins from both the varieties were found to be specific for mannose. The purified fluorescein isothiocyanate (FITC) -labelled lectins showed binding reaction with homologous as well as heterologous strains of Rhizobium spp. The results revealed that pea lectins are not highly specific to their respective rhizobia. Moreover, these lectins showed a greater stimulatory effect on homologous Rhizobium leguminosarum strains.
Plant Science, 2005
Transgenic rice (Oryza sativa L. cv. Murasaki) carrying genes encoding pea (Pisum sativum) lectin (PSL) or wild-soybean (Glycine soja) lectin-nucleotide phosphohydrolase (GS52) were inoculated with Rhizobium leguminosarum bv. viciae or Bradyrhizobium japonicum USDA110, respectively, as well as with Rhizobium sp. NGR234, and root colonization was assessed in comparison to comparably inoculated control plants. The data showed that expression of PSL and GS52 significantly promoted rhizobial colonization of root epidermal cells including root hairs in rice. In addition, in the case of R. leguminosarum bv. viciae and B. japonicum USDA110 colonization of the psl and gs52 transgenic rice plants, respectively, the bacterial cells were found to preferentially home towards and aggregate maximally at the root hair tip regions rather than on the root hair ''stalks''. The above data suggest that the lectins PSL and GS52, which participate in rhizobial recognition by root epidermal cells in pea and soybean, respectively, are also able to facilitate rhizobial attachment and colonization of the epidermal cells in rice roots. Moreover, aggregation of R. leguminosarum bv. viciae and B. japonicum USDA110 cells preferentially at root hair tip regions suggest that similar to legumes, the PSL and GS52 lectins are targeted to the root hair tips in transgenic rice, enabling higher bacterial attachment/colonization at the tip region. Rhizobial colonization at root hair tips in the psl and gs52 rice plants frequently led to the localized dissolution of the cell wall creating perforations at the tip region. It is likely that the presence of lectins, such as PSL and GS52 leads to structural modifications in cell wall organization of the root hair/epidermal cells, making them prone to localized dissolution by the hydrolytic activity of compatible rhizobia to permit invasion of the root cells. #