Jillian M. Hagel

Publications (2)5.73 Total impact

• Article: Opium poppy: blueprint for an alkaloid factory

  Peter J. Facchini, Jillian M. Hagel, David K. Liscombe, Natalia Loukanina, Benjamin P. MacLeod, Nailish Samanani, Katherine G. Zulak
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  ABSTRACT: Opium poppy (Papaver somniferum) produces a large number of benzylisoquinoline alkaloids, including the narcotic analgesics morphine and codeine, and has emerged as one of the most versatile model systems to study alkaloid metabolism in plants. As summarized in this review, we have taken a holistic strategy—involving biochemical, cellular, molecular genetic, genomic, and metabolomic approaches—to draft a blueprint of the fundamental biological platforms required for an opium poppy cell to function as an alkaloid factory. The capacity to synthesize and store alkaloids requires the cooperation of three phloem cell types—companion cells, sieve elements, and laticifers—in the plant, but also occurs in dedifferentiated cell cultures. We have assembled an opium poppy expressed sequence tag (EST) database based on the attempted sequencing of more than 30,000 cDNAs from elicitor-treated cell culture, stem, and root libraries. Approximately 23,000 of the elicitor-induced cell culture and stem ESTs are represented on a DNA microarray, which has been used to examine changes in transcript profile in cultured cells in response to elicitor treatment, and in plants with different alkaloid profiles. Fourier transform-ion cyclotron resonance mass spectrometry and proton nuclear magnetic resonance mass spectroscopy are being used to detect corresponding differences in metabolite profiles. Several new genes involved in the biosynthesis and regulation of alkaloid pathways in opium poppy have been identified using genomic tools. A biological blueprint for alkaloid production coupled with the emergence of reliable transformation protocols has created an unprecedented opportunity to alter the chemical profile of the world’s most valuable medicinal plant.
  Phytochemistry Reviews 04/2012; 6(1):97-124. · 4.33 Impact Factor
• Article: Hydroxycinnamic acid amide metabolism: physiology and biochemistry

  Peter J Facchini, Jillian Hagel, Katherine G Zulak
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  ABSTRACT: Hydroxycinnamic acid amides (HCAAs) are a widely distributed group of plant secondary metabolites purported to function in several growth and developmental processes including floral induction, flower formation, sexual differentiation, tuberization, cell division, and cytomorphogenesis. Although most of these putative physiological roles for HCAAs remain controversial, the biosynthesis of amides and their subsequent polymerization in the plant cell wall are generally accepted as integral components of plant defense responses to pathogen challenge and wounding. Tyramine-derived HCAAs are commonly associated with the cell wall of tissues near pathogen-infected or wound healing regions. Moreover, feruloyltyramine and feruloyloctapamine are covalent cell wall constituents of both natural and wound periderms of potato (Solanum tuberosum) tubers, and are putative components of the aromatic domain of suberin. The deposition of HCAAs is thought to create a barrier against pathogens by reducing cell wall digestibility. HCAAs are formed by the condensation of hydroxycinnamoyl-CoA thioesters with phenylethylamines such as tyramine, or polyamines such as putrescine. The ultimate step in tyramine-derived HCAA biosynthesis is catalyzed by hydro xycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase (THT; E.C. 2.3.1.110). The enzyme has been isolated and purified from a variety of plants, and the corresponding cDNAs cloned from potato, tobacco (Nicotiana tabacum), and pepper (Capsicum annuum). THT exhibits homology with mammalian spermidine-spermine acetyl transferases and putative N-acetyltransferases from microorganisms. In this review, recent advances in our understanding of the physiology and biochemistry of HCAA biosynthesis in plants are discussed.Key words: hydroxycinnamic acid amides, hydroxycinnamoyl-CoA thioesters, metabolic engineering, phenylethylamines, plant cell wall, polyamines, secondary metabolism, tyramine.
  Canadian Journal of Botany 02/2011; 80(6):577-589. · 1.40 Impact Factor