HYDROXYGERANYLLINALOOL GLYCOSIDES FROM TOBACCO EXHIBIT ANTIBIOSIS ACTIVITY IN THE TOBACCO BUDWORM [HELIOTHIS-VIRESCENS (F)]

Leaves of Tobacco Introduction TI-165 were found to be resistant to to bacco budworm [Heliothis virescens (F.)] attack. HPLC profiles of leaf extracts showed that TI-165 had relatively high levels of two compone nts (A and B) that were absent in susceptible varieties. Compounds A a nd B were isolated from TI-165 by a combination of preparative C-18, s ilicic acid column, and centrifugal thin-layer chromatography. They we re identified as diterpene glycosides: compound A, L-rhamnopyranosyl-( 1-->6)]-beta-D-glucopyranoside; compound B, a-L-rhamnopyranosyl(1-->4) ]-beta-D-glucopyranoside (hydroxygeranyllinalool glycosides). Budworm bioassays with whole tobacco leaves and purified mixtures of A and B s howed significant correlation between larval weights and levels of A a nd B. HPLC analyses of freeze-dried leaves of 68 Nicotiana species ind icated that 26 species had high levels of diterpene glycosides identic al to or related to A and B.