Assignment of UVB-responsive cis-element and protoplastization-(dilution-) and elicitor-responsive ones in the promoter region of a carrot phenylalanine ammonia-lyase gene (gDcPAL1)

Expression of a carrot phenylalanine ammonia-lyase (PAL) gene (gDcPAL1) in suspension-cultured carrot cells is induced by dilution of the culture or by application of a fungal elicitor, as well as by ultraviolet B (UVB) irradiation. We demonstrated that among its upstream cis-elements (Takeda et al. 1997] Photochem. Photobiol. 66, 464-470), L4 is UVB responsive, and L1 is protoplastization- (dilution-) and elicitor responsive, from studies with transiently transformed mutated or truncated g-DcPAL1 promoter-luc constructs. This conclusion is consistent with our observation that PAL activities induced by UVB and by protoplastization (dilution) or elicitor are additive.