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Overexpression of the Arabidopsis thaliana squalene synthase gene in Withania coagulans hairy root cultures increases the biosynthesis of phytosterols and withanolides

2009, New Biotechnology

ABSTRACTS ten days of culture (P < 0.01). These findings could be correlated with PPP stimulation. doi:10.1016/j.nbt.2009.06.807 4.1.26 Methyl jasmonate elicitation and reactive oxygen species production in Rubia tinctorum cell suspension cultures M. Perassolo ∗ , C.V. Quevedo, V.D. Busto, A.B. Cardillo, C.A. Martínez, A.M. Giulietti, J. Rodríguez Talou Facultad de Farmacia y Bioquimica, UBA, Buenos Aires, Argentina Elicitation is a useful strategy to induce accumulation of secondary metabolites in plants. Besides the production of secondary metabolites, the defense response against elicitation also triggers the generation of reactive oxygen species (ROS), and can also lead to cell death. In particular, methyl jasmonate (MeJ) is a well-described agent that has been widely used to enhance anthraquinone (AQs) production in Rubia tinctorum. AQs biosynthesis involves different metabolic routes: o-succinylbenzoate, precursor of A and B rings, is derived from ␣-ketoglutarate and isochorismic acid. This is produced by the isochorismate synthase from chorismic acid, which is the end-product of shikimate pathway. C ring is derived from the terpenoid pathway. It has been proposed that proline cycle could be coupled to the pentose phosphate pathway (PPP) as the NADP+ generated by proline reduction from glutamate could act as cofactor of the first enzymes of the PPP. This pathway generates erithrose-4-phosphate, the substrate of the shikimate pathway. The aim of the present work was to study the relationship between MeJ elicitation, ROS, proline cycle and anthraquinone production in R. tinctorum cell suspension cultures. Cell cultures were treated with MeJ, diphenyl iodonium (DPI, an inhibitor of H2 O2 generation) and a glucose/glucose oxidase system (Glu/GOD, a H2 O2 generating-system). After 48 hours of culture, MeJ increased AQs content (53%, P < 0.05) compared to control cells, but not after 24 hours. Treatment with DPI of both control and MeJ-treated cells showed less AQs accumulation at 24 (26% and 33% less) and at 48 hours of culture (18.5% and 51% less, compared to both treatments without DPI). The Glu/GOD system induced AQs production (14 and 48% more than the control treatment, after 24 and 48 hours of culture). MeJ treatment increased proline content at 48 hours of culture (22% more), while it was decreased when DPI was added to MeJ-treated cells (28% less). Relationship between ROS and elicitation is currently under study. doi:10.1016/j.nbt.2009.06.808 S334 www.elsevier.com/locate/nbt New Biotechnology · Volume 25S · September 2009 4.1.27 Overexpression of the Arabidopsis thaliana squalene synthase gene in Withania coagulans hairy root cultures increases the biosynthesis of phytosterols and withanolides M. Hossein Mirjalili 1,∗ , M. Bonfill 3 , E. Moyano 2 , R.M. Cusido 3 , J. Palazón 3 1 Department of Agriculture, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, G. C., Evin, Tehran, Iran 2 Departament de Ciencies Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain 3 Laboratori de Fisiologia Vegetal, Facultat de Farmacia, Universitat de Barcelona, Barcelona, Spain Squalene synthase (SS) is able to dimerize two molecules of farnesyl diphosphate to synthesize squalene, a shared precursor in steroid and triterpenoid biosynthesis in plants. The SS1 gene encoding SS from Arabidopsis thaliana was introduced in Withania coagulans under the control of the CaMV35S promoter together with the TDNA of Agrobacterium rhizogenes A4. The engineered hairy roots were studied for withanolide production and phytosterol accumulation and the results were compared with those obtained from control roots harbouring only the T-DNA from pRiA4. Both kinds of roots were able to biosynthesize the most important bioactive withanolides, withanolide A and withaferin A, the latter only in very low concentrations. The engineered root line SS135 exhibited the highest withanolide content (4.93 ␮g/g DW), more than doubling the most productive control (C26), and thereby showing the effectiveness of the transgene in increasing withanolide production. This root type also exhibited a greater capacity than the control (nearly threefold) for accumulating squalene-derived primary metabolites such as phytosterols. doi:10.1016/j.nbt.2009.06.809 4.1.28 Pathway activity profiling (papi): an integration system for metabolomics data R. Aggio ∗ , K. Ruggiero, S. Villas-Boas The Auckland University, Auckland, New Zealand Metabolomics has gained increased popularity in the last ten years. This popularity comes from its use as a functional genomics tool and its diverse range of potential applications. The ultimate goal for metabolomics is its integration with other omics-related data. However, today there is no straightforward method able to combine the results from different omics. These type of data are usually complex, difficult to interpret and even more difficult to correlate. As a consequence, the data analysis requires sophisticated bioinformatic tools coupled to strong background knowledge on chemistry, biochemistry and molecular biology. Metabolomics data, in particular, are the most difficult to interpret because of the non-direct linkage between metabolites and genes. In this work we present a new method to correlate metabolite levels to potential metabolic pathways likely to be active inside the cells. This