Figure 4: Gibberellins regulate M. truncatula infection depending on DELLA proteins.

(a) Quantification of infection events per root in wild type (WT), with or without GA₃ (1 μM) or in della mutants. Results are shown as percentages relatively to the WT untreated control. (b) Relative number of infection events in roots expressing the pMtDELLA1:della1-Δ18 construct. Results are shown as percentages relatively to the empty vector used as control. (c) Representative images of nodule primordia (left panels) in roots expressing the empty vector (top) or in roots expressing the pMtDELLA1:della1-Δ18 construct (bottom). Details of infected root hairs are shown in right panels. Square brackets indicate infection threads. Scale bars, 100 μm. In (a,b), dotted lines indicate a ratio of 100%. In all cases, quantifications were performed 7 days post inoculation with a S. meliloti expressing a LACZ reporter. Error bars represent confidence intervals (α=0.05, n>10 plants), and letters and star indicate significant differences based on a Kruskal and Wallis test (α<0.05) for a and a Mann–Whitney test (α<0.05) for b. One representative example out of two biological replicates is shown.