Fig. 1

Transient expression of reporter genes in wild strawberry using Agrobacterium-mediated infiltration. (A) Agroinfiltration of a F. vesca leaf was initially conducted by infiltrating at a single spot (single infiltration, left panel) on the abaxial side of the leaf. The right panel shows a leaf infiltrated in multiple spots to ensure comprehensive coverage of the leaf surface. (B) Confocal laser-scanning microscopy images of F. vesca leaf cells transfected with the GFP expression cassette at 3 days after infiltration (DAI). CaMV 35S pro represents the strong constitutive Cauliflower mosaic virus (CaMV) 35S promoter. NOS ter indicates the terminator sequence of the nopaline synthase (NOS) gene. Scale bars represent 50 μm. (C) Spatial expression of the GUS reporter in agroinfiltrated F. vesca leaves at 3 DAI. Agrobacterium carrying the GUS expression cassette was infiltrated into one half of each F. vesca leaf (+), and the other half of the leaf was used as the non-infiltrated control (−). (D) Transient expression of the GUS reporter in agroinfiltrated F. vesca leaves at 3 DAI. F. vesca leaves were infiltrated with solutions containing different strains of Agrobacterium harboring pBI121, a binary vector containing the bacterial β-glucuronidase (GUS) gene. NT represents control leaf samples with no transfection. Error bars show standard deviations of the mean GUS activity in four agroinfiltrated leaves from two biologically independent experiments (n = 4). Different letters indicate statistically significant differences in mean GUS activity, as analyzed by one-way ANOVA with Tukey’s HSD test at p = 0.05. (E) Agrobacterium injection to introduce a gene expression cassette into vascular cells of wild strawberry runners. (F) Expression of the GFP reporter in an injected strawberry runner. CLSM was used to observe GFP expression in cross-sections of the apical ends at 3 DAI. Scale bars represent 200 μm.