SYNTHESIS AND AGROBACTERIUM VIR-INDUCING ACTIVITIES OF CONIFERYL ALCOHOL BETA-GLYCOSIDES

Coniferyl alcohol beta-glycosides were synthesized by coupling coniferyl alcohol sodium salt in aqueous acetone with peracetylated glycosyl halides of D-glucopyranose, D-galactopyranose and L-fucopyranose. After O-deacetylation by sodium methoxide, the glycosides were tested for their potential air gene-inducing activities in Agrobacterium tumafaciens A348/pSM358 and A348/pSM243cd harbouring, respectively, vitE:lacZ and virB::lacZ fusion plasmids. In the large range of concentrations tested, these synthetic derivatives had oil-inducing activity on strain A348/pSM358: D-Gal > D-Glc. The dose-response curves of these glycosylated compounds were completely different from those of free coniferyl alcohol; the beta-galactopyranoside at 500 mu M exhibited interestingly a greater activity than the free aglycone after a 12 hr incubation period. The coniferyl alcohol beta-glucopyranoside was a better inducer than the related beta-galactopyranoside on strain A348/pSM243cd. The beta-L-fucopyranoside was inactive with both A. tumefaciens strains. The activities of these glycosylated inducers were correlated with the presence of intracellular glycosylhydrolases from the various A. tumefaciens strains studied. It is noteworthy that the vir-gene induction activity of the coniferyl alcohol beta-galactopyranoside on strain A348/pSM358 was due to a high basal level of expression of the virE::lacZ fusion gene.