Fig. 3.

AM phenotype of M. truncatula roots and transgenic roots expressing a dominant DELLA1 gene (della1-Δ18) after GA₃ treatment. (A and B) Fluorescence/differential interference contrast overlay images of G. versiforme in roots of M. truncatula after treatment with solvent (A) or GA₃ (B). The arrow in A marks an arbuscule. Arbuscules are absent in GA₃-treated roots. (C) Infected root length in GA₃-treated roots does not differ from control. Data are averages ± SEM (n ≥ 31). (D) Morphology of G. versiforme in roots expressing della1-Δ18 after treatment with GA₃. Arbuscule formation is restored. (E) Percentage of infected root sections containing only intercellular hyphae or arbuscules after GA₃ treatment in roots expressing a vector control or della1-Δ18. Data are averages ± SEM from two independent experiments (n ≥ 10). (Scale bars: 50 µm.)