Extended Data Fig. 8 |. Variovorax degrades auxin and quenches auxin perception by the plant.

a, Primary root elongation of seedlings grown with six hormonal or microbial-associated molecular pattern RGI treatments (panels) individually (self) or with either Burkholderia CL11 or each of four Variovorax isolates (CL14, MF160, B4 and YR216). Significance was determined via ANOVA within each panel; letters correspond to a Tukey post hoc test. n = 74, 46, 61, 48, 49, 49, 45, 44, 46, 43, 49, 40, 22, 19, 22, 19, 20, 25, 28, 30, 29, 29, 29, 29, 12, 12, 21, 20, 19, 18, 26, 30, 30, 29, 30, 30, 29, 30, 30, 26, 29 and 28 biological replicates across 2 independent experiments. b, Variovorax degrades auxin. Growth curves showing optical density at OD₆₀₀ (top) and IAA concentrations (mg ml⁻¹) (bottom) in Variovorax CL14 cultures grown in M9 medium with different carbon sources. Left, IAA (+ 0.5% ethanol as solvent); middle, succinate; right, succinate and IAA (+ 0.5% ethanol as solvent). c, Variovorax quenches induction of the auxin bioreporter DR5::GFP. Quantification of GFP intensity in DR5::GFP Arabidopsis seedlings grown with no bacteria, Arthrobacter CL28 and Arthrobacter CL28 + Variovorax CL14. GFP fluorescence was imaged 1, 3, 6, 9 and 13 d after inoculation, and quantified in the root elongation zone. Significance was determined via ANOVA within each time point, while controlling for experiment, and denoted with asterisks. n = 20 biological replicates across 2 independent experiments. d, Representative primary root images of DR5::GFP plants quantified in c, showing roots from 1, 3 and 6 d after inoculation. In addition to the bacterial treatments shown in c, an exogenous IAA control is shown (IAA, second column), as well as IAA-treated plants inoculated with Variovorax CL14, illustrating that IAA-induced fluorescence is quenched in the presence of Variovorax CL14 within 3 d.