Participation of PLC/DAG/PKC pathway in elicitation with Chitosan of Rubia tinctorum

VASCONSUELO, A;; GIULIETTI, AM;; PICOTTO, G;; BOLAND R

Cordoba

Congreso; . XXXVII Reunion Anual de la Sociedad Argentina de Investigaciones en Bioquimica y Biologia Molecular -SAIB; 2001

The signal transduction pathway by which the plant elicitor Chitosan affects secondary metabolite formation in Rubia tinctorum was investigated. Chitosan significantly stimulated (_/100%) anthraquinone (Aqs) synthesis in cultured R. tinctorum. The action of the elicitor could be greatly reduced by inhibition of phospholipase C (neomycin, U-73122) and protein kinase C (PKC) (calphostin C, bisindolylmaleimide, PKC down-regulation). The phorbol ester PMA mimicked the effects of Chitosan on Aqs production. Furthermore, a marked increase in PKC activity and PKC a associated to the cell membranes was observed in response to the elicitor. Compound 2-APB, a blocker of IP3 receptor-mediated release of Ca2_ from inner stores, inhibited Chitosan stimulation of Aqs formation. These results indicate that Chitosan modulation of Aqs levels in R. tinctorum involves activation of the phopholipase C/PKC pathway, with the Ca2_-dependent PKC a isoform playing a major role.