LOLITREMS, PERAMINE AND PAXILLINE - MYCOTOXINS OF THE RYEGRASS ENDOPHYTE INTERACTION

Infection of perennial ryegrass (Lolium perenne L.) with appropriate s trains of the endophytic fungus Acremonium lolii Latch, Christensen et Samuels results in the production of a number of fungal secondary met abolites of which the insect antifeedant peramine and the lolitrem neu rotoxins are the best characterised. Peramine, a novel pyrrolopyrazine alkaloid, occurs in many endophyte/grass associations and is a highly active feeding deterrent to the Argentine stem weevil (Listronotus bo nariensis Kuschel). The lolitrems are complex indole terpenes associat ed particularly with the endophyte A. lolii and are considered respons ible for the ryegrass staggers toxicity syndrome shown by livestock gr azing endophyte-infected pastures. Lolitrem B is tremorgenic to mice a nd toxic to Argentine stem weevil. Paxilline, a weak tremorgen and pre sumed biosynthetic precursor of the lolitrems, is also produced by A. lolii. The chemistry and biological activity of peramine, lolitrem and paxilline is reviewed.