Induction of terpenoid biosynthesis in grapevine calluses by phaeoacremonium parasiticum

ESCORIAZA G; GATICA M; GIL M; BOTTINI R; PICCOLI P

Florencia

Congreso; 6th International Workshop on Grapevine Trunk Disseases (IWGTD); 2008

IWGTD

The grape disease ghoja de malvonh is associated with a xylophages fungi complex which includes Phaeoacremonium parasiticum. A normal plant response to pathogenic attack is the production of terpenic phytoalexins throughout cyclization of pharnesyl di-phosphate (FPP) by terpene-cyclase enzymes (TPS). The aim of this work was to evaluate TPS activity and to assess terpene biosynthesis in grape calluses inoculated or not with P. parasiticum. The TPS activity, analyzed as the amount of radioactive FPP ([3H]-FPP) transformed in hexane soluble products showed a significant augment with fungi dilutions of 2.106 cel.ƒÊL-1 and 2.107 cel.10ƒÊL-1 as compared with controls and calluses inoculated with lower dilutions (2.104 and 2.105 cel ƒÊL-1). As well, the metabolic profiles of the hexane fractions from control and inoculated calluses were assessed by capillary gas chromatography coupled with mass spectrometry (GC-MS). In inoculated calluses the biosynthesis of pinene (monoterpene) and cis-Nerolidol (sesquiterpene) increased as the fungi concentration was larger and in correlation with the TPS activity, while the amount of squalene (the triterperne key in sterol synthesis) decreased