Pulsed electric field stimulates plant secondary metabolism in suspension cultures of Taxus chinensis*

Abstract

The effects of pulsed electric field (PEF) on growth and secondary metabolite production by plant cell culture were investigated by using suspension cultures of Taxus chinensis as a model system. Cultured cells in different growth phases were exposed to a PEF (50 Hz, 10 V/m) for various periods of time. A significant increase in intracellular accumulation of taxuyunnanine C (Tc), a bioactive secondary metabolite, was observed by exposing the cells in the early exponential growth phase to a 30-min PEF. The Tc content (i.e., the specific production based on dry cell weight) was increased by 30% after exposure to PEF, without loss of biomass, compared with the control. The combination of PEF treatment and sucrose feeding proved useful for improving secondary metabolite formation. Production levels of reactive oxygen species, extracellular Tc, and phenolics were all increased, whereas cell capacitance was decreased with PEF treatment. The results show that PEF induced a defense response of plant cells and may have altered the cell/membrane's dielectric properties. PEF, an external stimulus or stress, is proposed as a promising new abiotic elicitor for stimulating secondary metabolite biosynthesis in plant cell cultures.

Responses of defense signals, biosynthetic gene transcription and taxoid biosynthesis to elicitation by a novel synthetic jasmonate in cell cultures of Taxus chinensis

“…In Taxus cell cultures, various elicitors have been used to stimulate taxoid production (e.g., Huang et al, 2005;Naill and Roberts, 2005;Qian et al, 2004a,b;Tabata, 2004;Wu and Ge, 2004;Ye et al, 2004). Regarding the elicitation mechanism, there are reports on defense responses such as oxidative burst, NO burst and/or JA by cultured cells of Taxus spp.…”

“…The biosynthesis of many plant secondary metabolites is a part of plant defense response to the attack by insects and pathogens, or to other biotic and abiotic environmental stresses. Strategies with application of biotic and abiotic elicitors have been developed to improve the yield of plant secondary metabolites such as in cell cultures of Taxus chinensis (e.g., Qian et al, 2004b;Tabata, 2004;Ye et al, 2004). Biotic elicitors can be glucan polymers, glycoproteins, or fungal cell materials, while abiotic elicitors include electric field, light, ultrasonication, osmotic pressure, heavy metals, cold or heat shock, and various chemicals.…”

Metabolomic evaluation of pulsed electric field-induced stress on potato tissue

“…ROS have been suggested to be part of the endogenous signal components required for elicitorinduced synthesis of secondary metabolites (Baker and Orlandi 1995), which are widely believed to be part of the defense response of plants to stress (Shohael et al 2006). When using PEF as stressor, interesting Wndings for the pharmaceutical Weld, such as the increased yields of a cytostatic compound in cell culture of Taxus chinensis (Ye et al 2004), and for the food science and nutrition Weld, such as the increased concentration of antioxidants and phytoesterols from oil seeds and fruits (Guderjan et al 2005(Guderjan et al , 2007Balasa 2007), encourage deeper metabolic studies that can help to a better understanding of the complex, dynamic metabolic behavior of plant tissues subjected to this novel (i.e. not present in nature) stress condition.…”

Transgenic mimicry of pathogen attack stimulates growth and secondary metabolite accumulation

“…via traditional breeding and screening (Buter et al 1998;Long et al 2006), through the expression of genes encoding key enzymes (Holmberg 1997;Dueckershoff et al 2005;Tian and Dixon 2006;Inui et al 2007;Liu et al 2007) or through functional genomics (Goossens et al 2003), but despite these successes, metabolic engineering of the relevant biosynthetic pathways is often hampered by a lack of knowledge of the enzymes and genes involved. Indirect approaches to improving metabolite production have thus been explored, including treating whole plants and in vitro cultures of organs or cells with inducers of plant defense responses, since the reaction to both biotic and abiotic stress can include increased accumulation of secondary metabolites (Lin and Wu 2002;Ye et al 2004;Matthews et al 2005;Wolucka et al 2005;Zhao et al 2005;Zobayed et al 2005;Shi et al 2007;Zhang and Fevereiro 2007).…”