Figure 2

Spectral properties and fluorescence quantification of GFP. Fluorescent protein was transiently expressed by co-infiltrating N. benthamiana leaf tissue with an Agrobacterium pSN.5 p19 culture plus a strain with no expression vector (Φ), or 5-fold dilutions of Agrobacterium containing pBin-35S-mGFP5 (mGFP5 at OD₆₀₀ 0.50, 0.10 and 0.02). (A) At 3 dpa, mGFP5 (green) fluorescence was imaged by leaf laser scanning. (B) In a plate reader, excitation (dotted lines) and emission spectra (solid lines) were measured from leaf discs of tissue agro-infiltrated with mGFP5 (green) or no expression vector (black). Relative fluorescence intensity (RFI) was plotted using mGFP5 peaks equal to 100. Ultraviolet (UV) wavelengths are in gray, visible spectrum colors were assigned as described [39]. (C) Box-plot graphs show quantification values from n = 8 samples/condition. Fluorescence intensity of leaf discs agro-infiltrated with mGFP5 strain dilutions, no expression vector (Φ) or non-treated samples (N) was acquired in monochromator-based (Infinite M200) and two filter-based (Appliskan and Victor X2) plate readers. Fluorescence intensity is expressed in arbitrary units (a.u.).