Figure 6.

Proposed model for TGA transcription factors in the regulation of PR1. A, Flow chart showing the genetic interactions between key regulatory components in the regulation of PR gene expression. Arrows represent activation and blocked arrows indicate repression. B, Mechanistic model showing recruitment of different factors under uninduced (−SA) and induced (+SA) conditions on the PR1 promoter. T, TGA transcription factors (TGA1–TGA6); T2, TGA2; N, NPR1; N*, activated NPR1; W, WRKY transcription factor; BTM, basal transcription machinery. The negative cis-regulatory elements, LS5 and LS4, are shown as hatched boxes and the positive element, LS7, is shown by a dotted rectangle. The dotted trans-acting factors represent an inactive form. Thickness of the arrow represents the level of expression and the blocked arrow represents repression.