G-PROTEINS PARTICIPATE IN THE CHITOSAN–INDUCED ANTHRAQUINONE PRODUCTION IN Rubia. tinctorum L.

VASCONSUELO1 ANDREA, PICOTTO2 GABRIELA, GIULETTI1 ANA M., A BOLAND2* RICARDO

Puerto Iguazu

Congreso; XXXX Reunión sociedad argentina de investigacion en bioquimica y biologia molecular; 2004

Plants have acquired economical importance due to the synthesis of secondary metabolites, but the levels produced in vitro are generally too low for commercial applications. Elicitation with chitosan (200 mg/l) significantly stimulated (@100%) anthraquinone (Aq) synthesis in R. tinctorum cell cultures. In previous studies we have shown that chitosan effects involve the activation of the phospholipase C (PLC)/protein kinase C (PKC) pathway, phosphoinositide 3’-OH-kinase (PI3K), the mitogenic activated protein kinase (MAPK) cascade and the participacion of Ca2+. Here we demonstrate that stimulation by the elicitor of Aq production could be blocked with 1 mM suramin, 1 mM GDPßS or with an anti-Gαq/11 antibody (20 mg/ml). In addition, chitosan elicitation could be mimicked by 10 mM mastoparan, 10 mM  AlF-4 or with 300 mM GTPgS. These evidences strongly suggest  that a G-protein, with immunological characteristics of Gαq/11 protein, is the nexus between chitosan extracellular signal and the intracellular messengers systems mentioned above.