Contribution of taxane biosynthetic pathway gene expression to observed variability in paclitaxel accumulation in Taxus suspension cultures

Abstract

Variability in product accumulation is one of the major obstacles limiting the widespread commercialization of plant cell culture technology to supply natural product pharmaceuticals. Despite extensive process engineering efforts, which have led to increased yields, plant cells exhibit variability in productivity that is poorly understood. Elicitation of Taxus cultures with methyl jasmonate (MeJA) induces paclitaxel accumulation, but to varying extents in different cultures. In this work, cultures with different aggregation profiles were established to create predictable differences in paclitaxel accumulation upon MeJA elicitation. Expression of known paclitaxel biosynthetic genes in MeJA-elicited cultures exhibiting both substantial (15-fold) and moderate (2-fold) differences in paclitaxel accumulation was analyzed using qRT-PCR. Each population exhibited the characteristic large increase in paclitaxel pathway gene expression following MeJA elicitation; however, differences in expression between populations were minor, and only observed for the cultures with the 15-fold variation in paclitaxel content. These data suggest that although upregulation of biosynthetic pathway gene expression contributes to observed increases in paclitaxel synthesis upon elicitation with MeJA, there are additional factors that need to be uncovered before paclitaxel productivity can be fully optimized.

Changes in gene transcription and taxane production in elicited cell cultures of Taxus×media and Taxus globosa

“…However, the total taxane production in the cell line after CD + CORO elicitation was higher than 35 mg/L, which is not reflected in the gene expression. Patil et al (2012), working with MeJA-elicited T. cuspidata cell cultures of different cell aggregate size, reported that differences in expression of several taxol biosynthetic genes were minor compared with differences in taxane accumulation. Consequently, there must be other factors controlling taxane biosynthesis besides the expression of the studied genes.…”

“…Consequently, no clear relationship was observed between BAPT and DBTNBT gene expression and the production of side chain-bearing taxanes. Patil et al (2012) observed that although taxane production is related with the expression of genes involved in the biosynthetic process, other factors may be involved, such as post-transcriptional and post-traductional regulation. However, since the other studied genes showed their highest expression after CD + CORO elicitation, or at least matching the levels in CORO-treated cultures, it seems likely that more taxol intermediates were produced by the dual treatment.…”

Two jasmonate-responsive factors, TcERF12 and TcERF15, respectively act as repressor and activator of tasy gene of taxol biosynthesis in Taxus chinensis

“…In addition, transcriptional expression of key enzyme genes was upregulated by MeJA (Laskaris et al 1999;Walker and Croteau 2001;Li et al 2012;Patil et al 2012). Tasy (taxadiene synthase) encodes an enzyme catalyzing GGPP to taxadiene, which was considered the determining point of the strength of taxol biosynthesis ( Fig.…”

Methyl jasmonate represses growth and affects cell cycle progression in cultured Taxus cells

“…While a number of studies have reported increased taxane biosynthetic pathway gene products upon MeJA elicitation (Jennewein et al 2004, Nims et al 2006, Patil et al 2012, Li et al 2012), there have been few reports regarding the role of MeJA on growth inhibition and cell cycle progression in Taxus cultures (Kim et al 2005, Naill and Roberts, 2005a). In the present study we investigate the influence of MeJA on both cell growth and viability of Taxus cells in batch culture.…”