Fig. 2: E. adhaerens T4 NF-dependent nodulation and T4 competitiveness.
From: Atypical rhizobia trigger nodulation and pathogenesis on the same legume hosts
a T4 harbors nod genes but lacks core nif genes. Heatmap representing the presence/absence of symbiotic genes in T4, T173, S. meliloti AK83, S. meliloti 1021 and S. fredii NGR234 using WSM419 as a reference. The color scale indicates the percentage of identities (amino acid, %) relative to WSM419 reference proteins. For each replicon carrying the nod genes of each strain, detected pseudogene and lacking genes are highlighted in gray and black, respectively. b–f The nodulation ability of the T4 strain relied on the production of Nod factors. b Confocal imaging of T4-GFP entering root hair through an infection thread. (Scale bars, 50 µm). Confocal imaging experiments consisted of four independent experiments. c, d Induction of the Nod factor-reporter construct proENOD11:gusA by WSM419 (c) and T4 (d) in 2-dpi primary root of A17 stable transformants expressing the gusA reporter fusion proENOD11:gusA (n = 12 plants). (Scale bars, 1 mm). e T4 nodABC genes are required to induce nodule formation. For mock, WSM419, T4 and T4ΔnodABC, n = 8, 16, 13 and 32 plants. Experiments have been repeated twice. f Nitrogen inhibits T4 nodule formation. For WSM419 0 mM NO3−, T4 0 mM NO3−, WSM419 5 mM NO3−, T4 5 mM NO3−, n = 39, 39, 30 and 12 plants. Experiments have been repeated twice. g T4 induced more nodules than WSM419 upon single inoculation and reduced the formation of WSM419 nodules when co-inoculated. Three biological replicates have been performed (n = 30 plants). h T4 did not fix nitrogen and reduced the nitrogen fixation of plants when co-inoculated with WSM419. Three biological replicates have been performed (n = 30 plants). i T4 dominated nodule formation over efficient nitrogen-fixing symbionts. Co-inoculation of T4 with nitrogen-fixing S. medicae and S. meliloti strains. Each boxplot reflects the analysis of 40 plants. e–i Plants were analyzed at 21 dpi. For each box-and-whisker plot, the box contains 50% of the data, the bottom and the top of the box represent Q1 and Q3, respectively, the center line indicates the median, the center cross indicates the mean, the whiskers indicate the data that range within 1.5 time the interquartile range and if they exist, outliers are shown. Asterisks indicate significant differences (***, P ≤ 0.001; P values in g = 9.10−13 and 7.10−10; P values in h = 3.10−19 and 7.10−10; Two-sided Student’s t-test). Source data for Fig. 2e-i are provided in Source Data file.
