%0 Journal Article %A Munoz Aguilar, J. Manuel %A Ashby, Alison M. %A Richards, Andrew J. M. %A Loake, Gary J. %A Watson, Martin D. %A Shaw, Charles H. %T Chemotaxis of Rhizobium leguminosarum biovar phaseoli towards Flavonoid Inducers of the Symbiotic Nodulation Genes %D 1988 %J Microbiology, %V 134 %N 10 %P 2741-2746 %@ 1465-2080 %R https://doi.org/10.1099/00221287-134-10-2741 %I Microbiology Society, %X 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. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-134-10-2741