Transient expression assays. Cotyledon explants from MT (A, B) and MT-Rg1 (C, D) were inoculated with Agrobacterium tumefaciens EHA105 harboring the gusA reporter gene (see Methods). For the transfection frequency (E) calculation, only explants showing coverage of more than 50% of the surface with GUS staining (A, C) were considered positive. Vertical bars indicate ± standard deviation of the mean (n = 30 explants). The absence of statistic significance (P ≤ 0.05, Student's t-test) is represented by n.s.