The Jasmonate-Responsive Element from the ORCA3 Promoter from Catharanthus roseus is Active in Arabidopsis and is Controlled by the Transcription Factor AtMYC2

Abstract

Jasmonates are plant signaling molecules that play key roles in protection against certain pathogens and against insects by switching on the expression of genes encoding defense proteins including enzymes involved in the biosynthesis of toxic secondary metabolites. In Catharanthus roseus, the ethylene response factor (ERF) transcription factor ORCA3 controls the jasmonate-responsive activation of terpenoid indole alkaloid biosynthetic genes. ORCA3 gene expression is itself induced by jasmonate. Its promoter contains an autonomous jasmonate-responsive element (JRE). Here we describe the jasmonate-responsive activity of the JRE from the ORCA3 promoter in Arabidopsis thaliana. We found that it interacts in vitro and in vivo with the basic helix-loop-helix transcription factor AtMYC2. Analysis of JRE-mediated reporter gene expression in an atmyc2-1 mutant background showed that the activity was strictly dependent on AtMYC2.

Jasmonate-responsive expression of paclitaxel biosynthesis genes in Taxus cuspidata cultured cells is negatively regulated by the bHLH transcription factors TcJAMYC1, TcJAMYC2, and TcJAMYC4

“…For example, the Arabidopsis bHLH MYC2 protein preferentially binds to the E-box sequence CACGTG. Furthermore, E-boxes are commonly found on the promoters of genes that respond to MJ (Dombrecht et al, 2007; Montiel et al, 2011). The Solanum JAMYC2 binds a related, “T/G-box” sequence (AACGTG) on the proteinase inhibitor promoter (Boter et al, 2004).…”

Analyses of Catharanthus roseus and Arabidopsis thaliana WRKY transcription factors reveal involvement in jasmonate signaling

“…While Arabidopsis does not produce TIAs or nicotine, CrMYC2 and NtMYC2 act in the jasmonte signaling pathway to regulate biosynthesis of these metabolites [16, 97]. Moreover, AtMYC2 can bind the jasmonate-responsive elements present in the promoter of Catharanthus ORCA3, an AP2/EFR TF gene, and activates its expression, illustrating the conserved nature of these orthologous regulators [98]. These reports further strengthen our reasoning for cross-species comparison of WRKY TFs from Catharanthus , Arabidopsis, and other medicinal plant to identify regulators conserved in jasmonate response and possibly secondary metabolite production.…”

Mapping cell fate decisions that occur during soybean defense responses

“…The shikimate pathway provides metabolites for the production of phenylpropanoids that are metabolized into substances that perform defense roles. The pathway involved in the biosynthesis of alkaloids from terpenoid and polykeytides that are jasmonate regulated (Menke et al 1999;Montiel et al 2011) and fatty acid biosynthesis (Savchenko et al 2010;Gao et al 2011;Meldau et al 2011) are also active. Some pathways appeared to be active at all points during the defense response, including increased activity of components of the arachidonic acid pathway (Klink et al 2011).…”