A phenylalanine ammonia-lyase gene from parsley: structure, regulation and identification of elicitor and light responsive cis-acting elements

Abstract

We demonstrate that phenylalanine ammonia-lyase (PAL) in parsley (Petroselinum crispum) is encoded by a small family of at least four genes. The levels of mRNA from three identified PAL genes increase considerably upon treatment of cultured parsley cells with UV light or fungal elicitor and upon wounding of parsley leaves or roots. In cultured cells these changes were shown to involve transcriptional activation. We present the first primary structure of a plant PAL gene (parsley PAL-1) and the deduced amino acid sequence of the enzyme. Inducible in vivo footprints in the PAL-1 promoter define two nucleotide sequences, within the motifs CTCCAACAAACCCCTTC and ATTCTCACCTACCA, involved in the responses to both UV irradiation and elicitor application. These motifs are conserved at similar positions in several elicitor or light-responsive genes from different species. In two cases they are found within short regions known to confer elicitor or UV-light inducibility. The conserved motifs in the parsley 4-coumarate:CoA ligase gene, which is coordinately regulated with PAL, also display UV-light inducible in vivo footprints. Taken together, our findings suggest a general role of these putative cis-acting elements in the responses of plants to such stresses.