Functional analysis of jasmonate-responsive transcription factors in Arabidopsis thaliana

Abstract

The aim of the studies described in this thesis was the functional analysis of JA-responsive transcription factors in Arabidopsis with an emphasis on the interaction with the promoters of their target genes. In short, the following new results were obtained. The promoter of the PDF1.2 gene contains at least two functionally equivalent GCC boxes instead of one as reported earlier (Brown et al., 2003). The JA biosynthesis genes AOC1 and AOC2 are direct target genes of ORA47, corroborating the notion that ORA47 controls JA biosynthesis via regulation of the biosynthesis genes (Pr_, 2006). JA controls ORA59 activity by promoting the nuclear localization and stabilization of the protein. JA-responsive nuclear localization is independent of the jasmonate receptor COI11, indicating the existence of an alternative jasmonate receptor. The JRE from the ORCA3 promoter is active in Arabidopsis and its activity is controlled by the bHLH transcription factor AtMYC2, suggesting that a related bHLH protein controls ORCA3 gene expression in Catharanthus.