Increasing morphinan alkaloid production by over‐expressing codeinone reductase in transgenic Papaver somniferum

Abstract

SummaryOnly plants of the Papaver genus (poppies) are able to synthesize morphinan alkaloids, and cultivation of P. somniferum , opium poppy, remains critical for the production and supply of morphine, codeine and various semi-synthetic analgesics. Opium poppy was transformed with constitutively expressed cDNA of codeinone reductase ( PsCor1.1 ), the penultimate step in morphine synthesis. Most transgenic lines showed significant increases in capsule alkaloid content in replicated glasshouse and field trials over 4 years. The morphinan alkaloid

Benzylisoquinoline alkaloid biosynthesis in opium poppy

“…Opium poppy plants engineered with constitutively expressed or antisense-suppressed NMCH showed substantial modulations in overall alkaloid content, but the BIA profile was not altered ). In contrast, overexpression of COR (Larkin et al 2007) and SalAT (Allen et al 2008) specifically resulted in increased morphinan alkaloid accumulation. Surprisingly, the RNAi-mediated silencing of COR (Allen et al 2004) did not result in the accumulation of codeine, but rather caused a substantial accumulation of (S)-reticuline and a concomitant decrease in the levels of morphine pathway intermediates downstream of salutaridine.…”

“…The RNAi-mediated suppression of COR transcript levels resulted in the accumulation of reticuline and methylated 1-benzylisoquinoline derivatives with a corresponding decrease in morphinan alkaloid content (Allen et al 2004). In support of a role for COR in the modulation of morphine biosynthesis, over-expression of COR resulted in a significant increase in morphinan alkaloid levels (Larkin et al 2007). Similarly, over-expression of SalAT also increased morphinan alkaloid content, whereas suppression of SalAT transcript levels caused the accumulation of salutaridine, but did not alter the abundance or profile of morphinan alkaloids (Allen et al 2008).…”

“…However, SalAT and COR transcripts have also been reported in the cytoplasm, or latex, of laticifers (Decker et al 2000;Larkin et al 2007;Allen et al 2008), although in situ hybridization and immunofluorescence labeling failed to detect SalAT and COR mRNA and corresponding enzymes in laticifers (Bird et al 2003;weid et al 2004;Samanani et al 2006). Recently, the application of shotgun proteomics to determine the relative abundance of proteins in isolated latex, or in whole stem including latex, revealed that the final three steps in morphine biosynthesis, catalyzed by T6ODM, COR and CODM, occur primarily in laticifers (Onoyovwe et al 2013).…”

Removal of Substrate Inhibition and Increase in Maximal Velocity in the Short Chain Dehydrogenase/Reductase Salutaridine Reductase Involved in Morphine Biosynthesis

“…Pentacyclic morphinan alkaloids possess several chiral centers, which preclude chemical synthesis as an option for the efficient production of these widely used pharmaceuticals. Therefore, the worldwide supply of these narcotic compounds is still achieved by their isolation mainly from the opium poppy, Papaver somniferum L. With the availability of an increasing number of isolated genes encoding several pathway enzymes, recent interest has focused on the qualitative and quantitative modulation of the alkaloid profile in transgenic opium poppy plants (2)(3)(4)(5)(6), the production of BIAs in microbes (7,8), and de novo synthesis by a combination of chemical and biochemical conversions. BIA biosynthesis begins with the condensation of the tyrosinederived precursors dopamine and p-hydroxyphenylacetaldehyde to (S)-norcoclaurine (see Fig.…”

Improvement of Benzylisoquinoline Alkaloid Productivity by Overexpression of 3′-Hydroxy-<i>N</i>-methylcoclaurine 4′-<i>O</i>-Methyltransferase in Transgenic <i>Coptis japonica</i> Plants

“…In the biosynthesis of benzylisoquinoline alkaloids, several papers have reported successful alteration of productivity and unexpected accumulation of alkaloids. Overexpression of Ps codeinone reductase (COR), CYP80B3, and salutaridinol 7-O-acetyltransferase (SalAT) resulted in an increase of the morphinan alkaloid in the latex of Ps [8][9][10] and overexpression of the Ps berberine bridge enzyme (BBE) in Eschscholzia californica (Ec) root culture, resulting in increased levels of the end products, benzophenanthridine alkaloids. 11) Overexpression of Cj6OMT in Ec-cultured cells also resulted in an effective increase of benzophenanthridine alkaloids.…”