As mentioned above, TGA factors can regulate gene expression in response to salicylic acid (SA) in either an NPR1- or NPR1-independent manner. During our search for TGA-interacting proteins that might play a role in NPR1-independent processes, we have identified Scarecrow like (SCL) 14, a member of the GRAS family of proteins, as an interacting protein. GRAS proteins are regulatory proteins that are involved in a variety of different biological processes like e.g. gibberrellic acid signalling or root patterning. Using chromatin immunoprecipitation assays we have shown that TGA factors recruit SCL14 to a certain type of salicylic acid-inducible promoters (Fode et al., submitted). Whole genome microarray analysis has revealed a number of genes that are regulated by the TGA/SCL14 complex. These genes seem to play a role in the detoxification of chemicals or reactive molecules that are formed during a plant-pathogen interaction. Consistently, these genes are not only inducible by salicylic acid, but also by hydrogen peroxide, phytoprostanes or xenobiotics. Indeed, tga and scl14 mutants are more sensitive to these compounds. We aim to elucidate the mechanisms that lead to the activation of these genes.

PhD students: Ben Fode (2005-2008)

Publications: Fode et al. 2008, submitted