CrMYC1, a Catharanthus roseus elicitor- and jasmonate-responsive bHLH transcription factor that binds the G-box element of the strictosidine synthase gene promoter

Abstract

A cDNA encoding a bHLH transcription factor was isolated by the yeast one-hybrid system from a Catharanthus roseus cDNA library using the G-box element of the Strictosidine synthase gene promoter as bait. The corresponding protein (named CrMYC1) was shown to bind specifically to the G-box in yeast. In C. roseus suspension cells CrMYC1 mRNA levels are induced by fungal elicitor and jasmonate suggesting that CrMYC1 may be involved in the regulation of gene expression in response to these signals.

Identification of a Bipartite Jasmonate-Responsive Promoter Element in the Catharanthus roseus ORCA3 Transcription Factor Gene That Interacts Specifically with AT-Hook DNA-Binding Proteins

“…The cold-responsive expression of the CBF genes is controlled by the bHLH transcription factor INDUCER OF CBF EXPRESSION1 (Chinnusamy et al, 2003). A G box in the STR promoter was also shown to bind bHLH proteins (Pré et al, 2000;Chatel et al, 2003). It is interesting in this context that the gene encoding the bHLH protein CrMYC1 showed JA-responsive expression (Chatel et al, 2003).…”

“…A G box in the STR promoter was also shown to bind bHLH proteins (Pré et al, 2000;Chatel et al, 2003). It is interesting in this context that the gene encoding the bHLH protein CrMYC1 showed JA-responsive expression (Chatel et al, 2003). The STR G box also binds two bZIP proteins called G-box binding factor1 (CrGBF1) and CrGBF2, which acted as repressors of this promoter in transient assays (Sibéril et al, 2001).…”

Transcriptional regulation of plant inducible defenses against herbivores: a mini-review

“…As expected from their general defense-related function, MYC2-like TFs are found in highly conserved forms in many plant species (Heim et al 2003;Toledo-Ortiz et al 2003;Li et al 2006;Dombrecht et al 2007;Carretero-Paulet et al 2010;Todd et al 2010). Moreover, wounding, MeJA or herbivory have been reported to induce transient expression of MYC2 genes in Arabidopsis thaliana (Lorenzo et al 2004), Catharanthus roseus (Chatel et al 2003), Medicago truncatula (Naoumkina et al 2008), Nicotiana benthamiana (Todd et al 2010) and Nicotiana tabacum (Shoji et al 2008). Interestingly, three MYC2-like bHLH TFs have been reported in N. benthamiana that either positively (NbbHLH1 and NbbHLH2) or negatively (NbbHLH3) regulate nicotine biosynthesis (Todd et al 2010).…”

Perspectives of the Metabolic Engineering of Terpenoid Indole Alkaloids in Catharanthus roseus Hairy Roots

“…Research suggests that CrBPF-1 may enhance the expression of the Str gene when the ORCAs are already bound to the promoter [38]. CrMYC1 [39] and CrMYC2 [40] are basic helix-loop-helix transcription factors. Both of these two transcription factors are induced by JA and fungal elicitation.…”

“…Both of these two transcription factors are induced by JA and fungal elicitation. The mRNA levels of CrMYC1 and Str genes were enhanced after induction by JA and fungal elicitation, which suggests that CrMYC1 activates the expression of the Str gene [39]. CrMYC2 is postulated to act upstream of ORCA2 and ORCA3, activating their transcription [40].…”