Effect of two proline analogs on secondary metabolite production in Rubia tinctorum cultures.

PERASSOLO, M.; QUEVEDO, C.V.; GIULIETTI, A.M.; RODRÍGUEZ TALOU, J.

Puerto Madryn, Chubut, Argentina

Congreso; XLVI Reunión Anual de la SAIB; 2010

Anthraquinones (AQs) are the main secondary metabolites produced by Rubia tinctorum L through different metabolic routes. Chorismic acid, the end-product of shikimate pathway, becomes a branch point for primary and secondary metabolic pathways, and is an essential substrate for AQs biosynthesis. It has been proposed that the proline cycle could be coupled with the pentose phosphate pathway (PPP), since the NADP+ generated by proline reduction from glutamate could act as a cofactor of the first enzymes of the PPP. This pathway generates erithrose-4-phosphate, the substrate of the shikimate pathway. In order to study the effect of the addition of two proline analogs on the proline cycle, the PPP and AQs production, three different treatments (besides from control) were performed in R. tinctorum cell suspension cultures: azetidine-2-carboxylic acid (A2C, 25 µM) and thiazolidine-4-carboxylic acid (T4C, 100 and 200 µM). The addition of 200 µM of T4C resulted in an increase in AQs production and also in the stimulation of the proline cycle, since a higher accumulation of this aminoacid was obtained. No induction of the PPP was observed after the treatment with proline analogs, so it can be assumed that this route was not a limitant factor as a carbon donor to the shikimate pathway.