title: Uncoupled defense gene expression and antimicrobial alkaloid accumulation in elicited opium poppy cell cultures.
abstract: Treatment of opium poppy (Papaver somniferum L.) cell cultures with autoclaved mycelial homogenates of Botrytis sp. resulted in the accumulation of sanguinarine. Elicitor treatment also caused a rapid and transient induction in the activity of tyrosine/dopa decarboxylase (TYDC, EC 4.1.1.25), which catalyzes the conversion of L-tyrosine and L-dopa to tyramine and dopamine, respectively, the first steps in sanguinarine biosynthesis. TYDC genes were differentially expressed in response to elicitor treatment. TYDC1-like mRNA levels were induced rapidly but declined to near baseline levels within 5 h. In contrast, TYDC2-like transcript levels increased more slowly but were sustained for an extended period. Induction of TYDC mRNAs preceded that of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) mRNAs. An elicitor preparation from Pythium aphanidermatum was less effective in the induction of TYDC mRNA levels and alkaloid accumulation; however, both elicitors equally induced accumulation of PAL transcripts. In contrast, treatment with methyl jasmonate resulted in an induction of TYDC but not PAL mRNAs. The calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and the protein kinase inhibitor staurosporine partially blocked the fungal elicitor-induced accumulation of sanguinarine. However, only staurosporine and okadaic acid, an inhibitor of protein phosphatases 1 and 2A, blocked the induction of TYDC1-like transcript levels, but they did not block the induction of TYDC2-like or PAL transcript levels. These data suggest that activation mechanisms for PAL, TYDC, and some later sanguinarine biosynthetic enzymes are uncoupled.
authors: Department of Biological Sciences, University of Calgary, Alberta, Canada. pfacchin@acs.ucalgary.ca.
authors: P J
authors: PJ
authors: Facchini
authors: A G
authors: AG
authors: Johnson
authors: J
authors: J
authors: Poupart
authors: V
authors: V
authors: de Luca
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000470:Alkaloids / Q000096:biosynthesis* / Q000235:genetics; D053119:Benzophenanthridines; D002478:Cells, Cultured; D003517:Cyclopentanes / Q000494:pharmacology; D004296:Dopa Decarboxylase / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant; D007546:Isoquinolines; D003904:Mitosporic Fungi / Q000502:physiology; D005810:Multigene Family; D009892:Opium; D054883:Oxylipins; D010207:Papaver / Q000378:metabolism* / Q000382:microbiology; D010650:Phenylalanine Ammonia-Lyase / Q000096:biosynthesis; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010946:Plants, Medicinal; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects; D014445:Tyrosine Decarboxylase / Q000096:biosynthesis
chemical_list: D000085:Acetates; D000470:Alkaloids; D053119:Benzophenanthridines; D003517:Cyclopentanes; D007546:Isoquinolines; D054883:Oxylipins; D010937:Plant Growth Regulators; D012333:RNA, Messenger; D009892:Opium; C072239:methyl jasmonate; C005705:sanguinarine; D004296:Dopa Decarboxylase; D014445:Tyrosine Decarboxylase; D010650:Phenylalanine Ammonia-Lyase