Elicitor of the β-Thujaplicin Accumulation in Callus Cultures of Cupressus lusitanica.

Abstract

The addition of yeast extract to callus cultures of Cupressus Zusitanica leads to a large increase in the production of p-thujaplicin that acts as a phytoalexin of the treated cultures. y-Thujaplicin was not formed in any appreciable amounts. The content usually reached S-16 mg/g of dry weight of callus in 6 days of incubation after the addition of yeast extract. This accumulation of P -thujaplicin suggested the presence of elicitor components in the yeast extract. Therefore, the extract was fractionated by means of ethanol precipitation, ribonuclease treatment and complexation with the Fehling reagent. Some fractions of the extract actively induced the P -thujaplicin accumulation in the Cupressus Zusitanica callus. The most effective fraction was purified about 50 -fold over unfractionated extract, and was a polysaccharide which was composed of mainly mannose, glucose, and to a lesser degree ribose residues.