Transcriptional activation of genes during the defense response has been widely establish as a major level of regulation. However, the cis-elements and trans-acting factors involved in transcriptional activation have been characterized for only a few defense genes. In addition to positive regulation, there is also evidence for negative regulation of gene expression during the defense response. However, only 3 genes whose mRNAs are negatively regulated have been cloned and the cis elements and trans factors involved in their regulation are completely unknown. A major overall aim of this proposal is to identify and compare the mechanisms underlying the positive and negative regulation of genes involved in the defense response. A second major aim is to elucidate the mechanisms for the differential espression of the central phenylpropanoid and phytoalexin branch pathway genes.
