caa a22 4500 47710195X CHVBK 20180405111544.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF00196568 doi (NATIONALLICENCE)springer-10.1007/BF00196568 Suppression of fungal β-glucan-induced plant defence in soybean ( Glycine max L.) by cyclic 1,3-1,6-β-glucans from the symbiont Bradyrhizobium japonicum [Elektronische Daten] [Axel Mithöfer, Arvind Bhagwat, Markus Feger, Jürgen Ebel] The production of antimicrobial phytoalexins is one of the best-known inducible defence responses following microbial infection of plants or treatment with elicitors. In the legume soybean (Glycine max L.), 1,3-1,6-β-glucans derived from the fungal pathogen Phytophthora sojae have been identified as potent elicitors of the synthesis of the phytoalexin, glyceollin. Recently it has been reported that during symbiotic interaction between soybean and the nitrogen-fixing bacterium Bradyrhizobium japonicum USDA 110 the bacteria synthesize cyclic 1,3-1,6-β-glucans. Here we demonstrate that both the fungal and the bacterial β-glucans are ligands of β-glucan-binding sites which are putative receptors for the elicitor signal compounds in soybean roots. Whereas the fungal β-glucans stimulate phytoalexin synthesis at low concentrations, the bacterial cyclic 1,3-1,6-β-glucans appear to be inactive even at relatively high concentrations. Competition studies indicate that increasing concentrations of the bacterial 1,3-1,6-β-glucans progressively inhibit stimulation of phytoalexin synthesis in a bioassay induced by the fungal 1,3-1,6-β-glucans. Another type of cyclic β-glucan, a 1,2-β-glucan from Rhizobium meliloti, that does not nodulate on soybean, seems to be inactive as elicitor and as ligand of the β-glucan-binding sites. These results may indicate a novel mechanism for a successful plant-symbiont interaction by suppressing the plant's defence response. Springer-Verlag, 1996 Bradyrhizobium nationallicence Bacterial/fungal 1,3-1,6-β-glucans nationallicence Elicitor nationallicence Glycine nationallicence Phytoalexins nationallicence β-Glucanbinding sites nationallicence HG-APEA : 1-[2-(4-aminophenyl)ethyl]amino-l-[hexaglucosyl]deoxyglucitol nationallicence HG-AzPEA : l-[2-(4-azidophenyl)-ethyl]amino-l-[hexaglucosyl]deoxyglucitol nationallicence IC50 : concentration for half-maximal displacement nationallicence Mithöfer Axel Botanisches Institut der Universität, Menzinger Strasse 67, D-80638, München, Germany aut Bhagwat Arvind Agricultural Research Service, BARC-W, USDA, 20705, Beltsville, MD, USA aut Feger Markus Botanisches Institut der Universität, Menzinger Strasse 67, D-80638, München, Germany aut Ebel Jürgen Botanisches Institut der Universität, Menzinger Strasse 67, D-80638, München, Germany aut Planta Springer-Verlag 199/2(1996-06-01), 270-275 0032-0935 199:2<270 1996 199 425 https://doi.org/10.1007/BF00196568 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00196568 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mithöfer Axel Botanisches Institut der Universität, Menzinger Strasse 67, D-80638, München, Germany aut NATIONALLICENCE 700 1- Bhagwat Arvind Agricultural Research Service, BARC-W, USDA, 20705, Beltsville, MD, USA aut NATIONALLICENCE 700 1- Feger Markus Botanisches Institut der Universität, Menzinger Strasse 67, D-80638, München, Germany aut NATIONALLICENCE 700 1- Ebel Jürgen Botanisches Institut der Universität, Menzinger Strasse 67, D-80638, München, Germany aut NATIONALLICENCE 773 0- Planta Springer-Verlag 199/2(1996-06-01), 270-275 0032-0935 199:2<270 1996 199 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer