Fig. 4.

Induction of VRE-controlled GFP expression by AtVIP1 and its homologs. (A) Confocal microscopy analysis of GFP expression in N. benthamiana leaves three days after co-infiltration with two Agrobacterium strains carrying the VRE1-35Smin-GFP reporter construct and a construct expressing AtVIP1 or its indicated homologs. GFP signal is in green; plastid autofluorescence is in red. Images are single confocal sections, and they are representative of images obtained in three infiltrations performed on three different leaves, with two images recorded per infiltration. Scale bars = 100 μm. (B) Quantification of the VRE1-GFP reporter expression shown in (A). GFP signal was quantified using the LSM Pascal software (Zeiss) by measuring the total GFP fluorescence in one field inside the infiltration area with a low magnification objective (10×); all images used for fluorescence measurement were taken with the same settings. Basal signal measured in area infiltrated with VRE1-GFP alone was subtracted from the values measured for each experimental condition, and the signal obtained with AtVIP1 was set as 100%. Error bars represent SEM of N=3 independent biological replicates (leaves).