Fig. 1.

AvrXa27 activates the rice Xa27 promoter and triggers a Bs3-dependent HR in N. benthamiana. (A) Graphical representation of constructs used for promoter analysis. The Bs3, Xa27, xa27, and the xa27_mut promoters are displayed as yellow, brown, and orange arrows, respectively. A yellow box represents the Bs3 cds. The UPT_AvrBs3, and UPT_AvrXa27 boxes are shown as blue and black boxes, respectively. A black box with a white bar represents the UPT_AvrXa27* box of the xa27 promoter. Black arrows represent transcription start sites (TSS). The scale indicates distances from the ATG start codon. Numbers below the arrows denote the distances between the 3′ end of a UPT box and its TSS. The Bs3 cds is not drawn to scale. (B) The promoter-Bs3 cds and the 35S promoter-driven avr constructs (avrXa27 [Left] or avrBs3 [Right]) were expressed transiently in N. benthamiana leaves via A. tumefaciens. Asterisks (*) mark areas in which the avr construct but no promoter construct was infiltrated. Dashed lines mark the inoculated areas. Four days after infiltration, the leaves were cleared with ethanol to visualize the HR (dark areas).