Abstract
Phenylalanine ammonia-lyase (PAL) acts as the key enzyme in regulating phenylpropanoid metabolism. It has been revealed that the expression of DcPAL1 in suspension cultured carrot cells is induced by dilution effect, elicitation and UV-B irradiation and DcMYB1 acted as the transcriptional activator concerning to the induction of DcPAL1 expression by several stresses. Deletion analysis of the DcMYB1 promoter indicated that the promoter region between -138 and -97 were negative regulatory cis-element for the promoter activity. We isolated a transcription factor, DcEIL, that interact with this region using yeast one-hybrid system. The amino acid sequence of DcEIL had the similarity to that of ETHYLENE-INSENSITIVE3 (EIN3) that act in ethylene signal transduction. The level of DcEIL mRNA was unaffected by several stresses, whereas inhibition of proteasome-mediated proteolysis by MG132 treatment led to reduction of DcMYB1 mRNA level, suggesting that the post-transcriptional regulation of DcEIL might involve in the regulation of DcMYB1 expression.
