Figure 1.

WRKY proteins are key regulators of gene expression during SAR. (a,b) The PR-1 gene is thought to be regulated by three transcription factors: a TGA-bZIP factor and an unknown factor that activate transcription, and a WRKY factor that represses transcription [11]. SNI1 is a negative regulator of PR-1 gene expression, possibly acting through the WRKY factor. (b) NPR1 regulates PR-1 gene expression through interactions with the TGA-bZIP factor, and possibly with the other two transcription factors and/or with SNI1. (c) Common regulation of genes in the PR-1 regulon is proposed to occur through WRKY transcription factors acting either positively or negatively and in an NPR1-dependent fashion. Dashed lines indicate putative interactions.