Metabolism of Monoterpenes in Cell Cultures of Common Sage (Salvia officinalis)

Abstract

Leaves of common sage (Salvia officinalis) accumulate monoterpenes in glandular trichomes at levels exceeding 15 milligrams per gram fresh weight at maturity, whereas sage cells in suspension culture did not accumulate detectable levels of monoterpenes (<0.3 nanograms per gram fresh weight) at any stage of the growth cycle, even in the presence of a polystyrene resin trap. Monoterpene biosynthesis from [U-14C]sucrose was also virtually undetectable in this cell culture system. In vitro assay of each of the enzymes required for the sequential conversion of the ubiquitous isoprenoid precursor geranyl pyrophosphate to (+)-camphor (a major monoterpene product of sage) in soluble extracts of the cells revealed the presence of activity sufficient to produce (+)-camphor at a readily detectable level (>0.3 micrograms per gram fresh weight) at the late log phase of growth. Other monoterpene synthetic enzymes were present as well. In vivo measurement of the ability to catabolize (+)-camphor in these cells indicated that degradative capability exceeded biosynthetic capacity by at least 1000-fold. Therefore, the lack of monoterpene accumulation in undifferentiated sage cultures could be attributed to a low level of biosynthetic activity (relative to the intact plant) coupled to a pronounced capacity for monoterpene catabolism.The accumulation of terpenoid natural products in plant cell cultures has been successfully demonstrated in the cases of diterpenoids and sesquiterpenoids, but rarely in the case of monoterpenes. Thus, there are reports of the production of diterpenoid substances in culture at levels exceeding those of the intact plant (42,43) and the induced accumulation of sesquiterpene phytoalexins in culture is well documented (12,13,16), whereas most accounts ofmonoterpene accumulation in cell culture systems (1, 17, 44) describe either very low levels of production or compositional patterns that differ markedly from those of the intact plant.Monoterpenes in intact plants usually accumulate in the extracellular storage spaces of specialized secretory structures, such as glandular trichomes, resin ducts, or resin cavities (35),

Induction and Characterization of a Cytochrome P-450-Dependent Camphor Hydroxylase in Tissue Cultures of Common Sage (Salvia officinalis)

“…* weight) was observed in these undifferentiated cells, even when provisions wer; made for trapping this volatile, hydrophobic product (Falk et al, 1990). This lack of accumulation was attributed to the high rate of camphor catabolic activity of suspension cultures (Falk et al, 1990), a process that may mimic the metabolic turnover of camphor produced in the oil glands of the intact plant (Croteau et al, 1984. Altematively, many monoterpenes are toxic to plant suspension cultures (Brown et al, 1987) and the metabolism of camphor by sage cells might thus represent such a detoxification system (Benveniste et al, 1982;Hendry, 1986).…”

“…* weight) was observed in these undifferentiated cells, even when provisions wer; made for trapping this volatile, hydrophobic product (Falk et al, 1990). This lack of accumulation was attributed to the high rate of camphor catabolic activity of suspension cultures (Falk et al, 1990), a process that may mimic the metabolic turnover of camphor produced in the oil glands of the intact plant (Croteau et al, 1984.…”

Identification of benzoin obtained from calli of Styrax officinalis by HPLC

“…It is indicated that even under the optimum induction conditions the yield of essential oil by in vitro plant tissues and cells was generally less than that achieved by the intact untreated plant, and the inability of cultured plant cells and calli to accumulate significant amounts of monoterpenes could be due to the combined effect of lower enzymatic activity and their higher catabolic rate (Falk et al, 1990). Because they are the enzymes of the volatile aldehyde and alcohol synthesis path, the activity of lipoxygenase and hydroperoxide lyase has been found in in vitro-cultured plant tissues (Matsui et al, 1996;Williams & Hardwood, 1998;Fauconnier et al, 2001).…”

Aloe vera transformation: the role of Amberlite XAD-4 resin and antioxidants during selection and regeneration

“…Although gene transfer by particle bombardment is widely used in monocots, several factors were found to play a major role specifically in Aloe vera transformation: (1) the appropriate explants being competent for transformation and regeneration, (2) pretreatment of the explants using DTT and GA 3 before bombardment, (3) establishment of an appropriate stepwise increased liquid selection system, and (4) post-bombardment recovery procedure utilizing medium supplemented with amberlite XAD resin entrapped in alginate beads. Although amberlite is mainly used to trap and extract different secondary metabolite produce in vitro (Falk et al 1990), we cannot rule out the possibility that the beneficial effect of Amberlite can be attributed also to the possibility that medium-organic compounds are also trapped by the amberlite resin (Mucciarelli et al 2009). …”