Fig. 4.

Tandemly-arranged UPT boxes with distinct TAL effector specificity retain their function when combined into a single promoter. (A) Graphical representation of promoter constructs. Yellow arrows and boxes represent the promoters and cds, respectively of the Bs3 and Bs3-E genes. Bs3 and Bs3-E promoters differ only in their UPT boxes and are therefore displayed in identical color. Green, brown, and orange color represents the promoters (arrows) and cds (boxes) of the tomato Bs4, rice Xa27, and rice xa27 genes, respectively. Pink, black and blue boxes represent the UPT_{AvrBs3Δrep16}, UPT_AvrXa27, and UPT_AvrBs3 boxes, respectively. The black box with the white vertical line represents the nonfunctional UPT_AvrXa27* box of the rice xa27 gene. With exception of the Bs3 cds all elements are drawn to scale. (B) In planta analysis of the promoter constructs. The promoter constructs depicted in (A) were codelivered together with 35S promoter-driven avr genes into N. benthamiana leaves (displayed in boldface letters above each leaf) via A. tumefaciens. Asterisks (*) mark areas in which A. tumefaciens containing only a TAL effector gene were infiltrated. Dashed lines mark the inoculated areas. Four days after inoculation, the leaves were harvested and cleared with ethanol to visualize the HR (dark areas).