Comparison of the symbiotic properties of Bradyrhizobium ORS285 and the ΔT3SS mutant on various NF-dependent and NF-independent Aeschynomene species. (a) Number of nodules per plant elicited by Bradyrhizobium ORS285 (blue bars) and ORS285ΔT3SS (red bars) on various Aeschynomene species. (b) Acetylene-reducing activity (ARA) in various Aeschynomene plants inoculated with Bradyrhizobium ORS285 (blue bars) and ORS285ΔT3SS (red bars). A.U., Arbitrary Unit. Error bars in a and b represent s.d. (n=5). (c–e, h–j). Aspect of the nodules elicited by ORS285 and 285ΔT3SS on A. nilotica (c and h), A. uniflora (d and i) and A. afraspera (e and j). Bars, 1 mm. (f–k, g–l) Cytological observations of the A. afraspera nodules elicited by ORS285 (f and g) and 285ΔT3SS (k and l). Bars, 500 μm (f and l) and 100 μm (g and l). A full colour version of this figure is available at the ISME journal online.