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. 2013 Jun 11:4:182.
doi: 10.3389/fpls.2013.00182. eCollection 2013.

Role of the phloem in the biochemistry and ecophysiology of benzylisoquinoline alkaloid metabolism

Eun-Jeong Lee  1 , Jillian M Hagel, Peter J Facchini
Affiliations

Role of the phloem in the biochemistry and ecophysiology of benzylisoquinoline alkaloid metabolism

Eun-Jeong Lee et al. Front Plant Sci. .

Abstract

Benzylisoquinoline alkaloids (BIAs) are a diverse group of biologically active specialized metabolites produced mainly in four plant families. BIA metabolism is likely of monophyletic origin and involves multiple enzymes yielding structurally diverse compounds. Several BIAs possess defensive properties against pathogenic microorganisms and herbivores. Opium poppy (Papaver somniferum: Papaveraceae) has emerged as a model system to investigate the cellular localization of BIA biosynthesis. Although alkaloids accumulate in the laticifer cytoplasm (latex) of opium poppy, corresponding biosynthetic enzymes and gene transcripts are localized to proximal sieve elements and companion cells, respectively. In contrast, BIA metabolism in the non-laticiferous meadow rue (Thalictrum flavum; Ranunculaceae) occurs independent of the phloem. Evidence points toward the adoption of diverse strategies for the biosynthesis and accumulation of alkaloids as defensive compounds. Recruitment of cell types involved in BIA metabolism, both within and external to the phloem, was likely driven by selection pressures unique to different taxa. The biochemistry, cell biology, ecophysiology, and evolution of BIA metabolism are considered in this context.

Keywords: benzylisoquinoline alkaloid; laticifer; phloem; plant defense; sieve element.

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Figures

Figure 1
Figure 1
Schematic representation of the multicell model for the biosynthesis and accumulation of BIAs in opium poppy involving the coordinated participation of companion cells (cc), sieve elements (se), and laticifers (la). Biosynthetic enzymes are synthesized in companion cells and transported to sieve elements, where alkaloid biosynthesis occurs. The bulk of synthesized alkaloids are stored in neighboring laticifer networks. Other abbreviations: phloem parenchyma (pp), vascular cambium (vc), xylem parenchyma (xp), and xylem vessels (xy).
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References

    1. Barken I., Geller J., Rogosnitzky M. (2008). Noscapine inhibits human prostate cancer progression and metastasis in a mouse model. Anticancer Res. 28, 3701–3704 - PubMed
    1. Behmer S. T., Grebenok R. J., Douglas A. E. (2010). Plant sterols and host plant suitability for a phloem−feeding insect. Funct. Ecol. 25, 484–491 10.1111/j.1365-2435.2010.01810.x - DOI - PubMed
    1. Behmer S. T., Nes W. D. (2003). Insect sterol nutrition and physiology: a global overview. Adv. Insect Physiol. 31, 1–72 10.1016/S0065-2806(03)31001-X - DOI
    1. Bird D. A., Franceschi V. R., Facchini P. J. (2003). A tale of three cell types: alkaloid biosynthesis is localized to sieve elements in opium poppy. Plant Cell 15, 2626–2635 10.1105/tpc.015396 - DOI - PMC - PubMed
    1. Costa E. V., Pinheiro M. L., Barison A., Campos F. R., Salvador M. J., Maia B. H., et al. (2010). Alkaloids from the bark of Guatteria hispida and their evaluation as antioxidant and antimicrobial agents. J. Nat. Prod. 73, 1180–1183 10.1021/np100013r - DOI - PubMed

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