Correlation of the appearance of morphinan alkaloids and laticifer cells in germinating Papaver bracteatum seedlings

Abstract

The course of alkaloid accumulation and laticifer cell appearance was compared in germinating P. bracteatum seedlings. Seedlings of various ages (0-14 days old) were analyzed for their dopamine, thebaine, morphinan alkaloid immunoreactivity, and benzophenanthridine alkaloid levels. Simultaneous electron microscopic studies revealed that seedlings were devoid of laticifer initials until day 3, where-upon their numbers increased with time. The appearance of appreciable amounts of thebaine only occurred after day 4 of germination. Conversely, dopamine was rapidly formed at the onset of germination and reached millimolar concentrations well before laticifer cells were detected. Benzophenanthridine alkaloid levels remained fairly constant over the period analyzed. These results support the theory that the presence of laticifer cells is necessary for the accumulation of morphinan but neither benzophenanthridine alkaloids nor their mutual precursor, dopamine.

Phloem-Specific Expression of Tyrosine/Dopa Decarboxylase Genes and the Biosynthesis of Isoquinoline Alkaloids in Opium Poppy.

“…In aerial organs, the alkaloids are contained within the vesicle-rich cytoplasm of mature laticifers (Fairbairn and Djote, 1970;Fairbairn et al, 1974;Roberts et al, 1983;Nessler et al, 1985;Rush et al, 1985). Latex collected from unripe seed capsules (Figure 4, stage 6), stems, or young leaves exhibited a profile of extractable alkaloids that was both quantitatively and qualitatively similar, as shown in Figure 6.…”

Molecular Characterization of the Salutaridinol 7-O-Acetyltransferase Involved in Morphine Biosynthesis in Opium Poppy Papaver somniferum

“…Transcript of cyp80b1 was also detected in all plant organs analyzed (12). Accumulation of morphinan alkaloids is thought to correlate with the appearance of laticifer cells in the developing plant and in differentiating plant cell culture (32,33). A reticulated laticifer system associated with the vascular tissue is present through the aerial parts of the poppy plant.…”

Using AFLP markers for species differentiation and assessment of genetic variability of in vitro-cultured Papaver bracteatum (section Oxytona)

“…The production of morphinan alkaloids is known to be associated with cell differentiation and morphogenetic processes (Constabel, 1985;Kutchan et al, 1985;Kamo and Mahlberg, 1988;Szoke, 1998). Morphinan alkaloid synthesis is dependent on the presence of specialized cells known as laticifers (Roberts et al, 1983;Kutchan et al, 1985;Rush et al, 1985), which are absent in undifferentiated poppy cultures. The detection of such alkaloids often coincides with the development of laticifers in differentiated plant material that develop in a similar way to young seedlings.…”

“…The majority of reported alkaloids from callus and suspension Papaver bracteatum cultures are the benzophenanthridine type including sanguinarine, dihydrosanguinarine, and oxysanguinarine (Table 4), which are produced in minor quantities in intact plants of the genus Papaver but are found as the dominant constituents of undifferentiated callus and suspension cultures (Cline and Coscia, 1988). The biosynthesis of these alkaloids occurs at loci different to the laticifers associated with morphinan alkaloids (Kutchan et al, 1985). The characteristic phytochemical characters often used to aid species differentiation with species of section Oxytona are not produced by undifferentiated in vitro tissues.…”