EXPRESSION PATTERNS CONFERRED BY TYROSINE DIHYDROXYPHENYLALANINE DECARBOXYLASE PROMOTERS FROM OPIUM POPPY ARE CONSERVED IN TRANSGENIC TOBACCO/

Opium poppy (Papaver somniferum) contains a large family of tyrosine/d ihydroxyphenylalanine decarboxylase (tydc) genes involved in the biosy nthesis of benzylisoquinoline alkaloids and cell wall-bound hydroxycin namic acid amides. Eight members from two distinct gene subfamilies ha ve been isolated, tydc1, tydc4, tydc6, tydc8, and tydc9 in one group a nd tydc2, tydc3, and tydc7 in the other. The tydc8 and tydc9 genes wer e located 3.2 kb apart on one genomic clone, suggesting that the famil y is clustered. Transcripts for most tydc genes were detected only in roots. Only tydc2 and tydc7 revealed expression in both roots and shoo ts, and TYDC3 mRNAs were the only specific transcripts detected in see dlings. TYDC1, TYDC8, and TYDC9 mRNAs, which occurred in roots, were n ot detected in elicitor-treated opium poppy cultures. Expression of ty dc4,which contains a premature termination codon, was not detected und er any conditions. Five tydc promoters were fused to the beta-glucuron idase (GUS) reporter gene in a binary vector. All constructs produced transient GUS activity in microprojectile-bombarded opium poppy and to bacco (Nicotiana tabacum) cell cultures. The organ- and tissue-specifi c expression pattern of tydc promoter-GUS fusions in transgenic tobacc o was generally parallel to that of corresponding tydc genes in opium poppy. GUS expression was most abundant in the internal phloem of shoo t organs and in the stele of roots. Select tydc promoter-GUS fusions w ere also wound induced in transgenic tobacco, suggesting that the basi c mechanisms of developmental and inducible tydc regulation are conser ved across plant species.