Chemotaxis of Rhizobium leguminosarum biovar phaseoli towards flavonoid inducers of the symbiotic nodulation genes

• Published in: Journal of general microbiology Vol. 134; no. 10; pp. 2741 - 2746
• Main Authors: Aguilar, J.M.M, Ashby, A.M, Richards, A.J.M, Loake, G.J, Watson, M.D, Shaw, C.H
• Format: Journal Article
• Language: English
• Published: London Soc General Microbiol 01.10.1988; New York, NY Cambridge University Press
• Subjects: Agronomy. Soil science and plant productions; Bacteriology; Biological and medical sciences; chemotaxis; Economic plant physiology; flavonoids; Fundamental and applied biological sciences. Psychology; genes; Microbiology; Motility, taxis; nodulation; Rhizobium leguminosarum; symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Attractant; Symbiosis; Inheritance; Phenols; Vegetal microorganism relation; Bacteria; Environmental factor; Carbohydrate; Plant nodule; Rhizobiaceae; Rhizobium leguminosarum
• ISSN: 0022-1287; 1350-0872; 1465-2080
• DOI: 10.1099/00221287-134-10-2741

Department of Botany, University of Durham, Science Laboratories, South Road, Durham DH1 3LE, UK ICI Biological Products Business, PO Box 1, Billingham, Cleveland, TS23 1LB, UK ABSTRACT Summary: Chemotaxis of Rhizobium leguminosarum biovar phaseoli RP8002 towards a range of carbohydrates, phenolic compounds and flavonoids was assayed. Xylose (peak response 10 –4 M ), sucrose (peak response 10 –6 M ) and raffinose (peak response 10 –5 M ) were strong chemoattractants amongst the carbohydrates, whilst glucose, fructose, galactose and maltose produced little or no detectable response. Of the monocyclic phenolic compounds, vanillyl alcohol, p -hydroxybenzoic acid (both peak responses 10 –6 M ) and 3,4-dihydroxybenzoic acid (peak response 10 –4 M ) all evoked strong chemotactic responses. Amongst the nod -inducing flavonoids, apigenin and luteolin were both strong chemoattractants (peaks at 10 –5 M ) while naringenin produced a very low response. Competition experiments suggest that apigenin and luteolin are recognized by a common receptor, but that there exists a separate receptor for luteolin alone. The inhibitors of nod -induction, umbelliferone and acetosyringone, both produced strong chemotactic responses, with peaks at 10 –3 M and 10 –2 M respectively. This evidence is indicative of a role for chemotaxis towards nod -inducing flavonoids in the initiation of root nodule formation by rhizobia, and also suggests that chemotaxis may influence the host range of the interaction.