Effect of p19 on the agroinfection efficiency of a Tobacco mosaic virus -based vector. N. benthamiana leaves were infiltrated with mixtures of A. tumefaciens (A.t.) cells (OD600 1.0, or dilutions thereof) containing the binary plasmid pJL43:GFP and, in some treatments, pJL3:P19. pJL43:GFP has as its T-DNA a 35S promoter driven TMV vector with a green fluorescent protein (gfp) gene insert. When TMV RNA is transcribed from the T-DNA, the TMV vector initiates self-replication and expresses GFP. The GFP-expressing TMV vector can move cell-to-cell and systemically in plants. Photographs taken under UV light, where GFP appears green and non-GFP expressing tissue red. A. Leaves infiltrated with (i) 1:1 mix of A.t./pJL43:GFP + A.t./pJL4 (empty vector); (ii) 1:1 mix of A.t./pJL43:GFP + A.t./pJL3:p19; (iii) 1:1 mix of 1:50 dil of A.t./pJL43:GFP + undiluted A.t./pJL4; (iv)1:1 mix of 1:50 dil of A.t./pJL43:GFP + undiluted A.t./pJL3:p19. Photographed 3 days post infiltration (DPI). B. Fluorescent micrographs of infiltrated leaves, 3 DPI. Labelling same as in A. C. Systemic movement of TMV:GFP in N. benthamiana plant where a lower leaf was infiltrated with A.t./pJL43:GFP cells. Photo taken 11 DPI.