Phytotoxicity of Phaseollin to, and Alteration of Phaseollin by, Cell Suspension Cultures of Phaseolus vulgaris

Abstract

The effect of phaseollin [a pterocarpanoid phytoalexin] on growth and viability of cell suspension cultures of kidney bean P. vulgaris was determined. Phaseollin at 16 and 32 .mu.g/ml inhibited the growth of the cell suspension cultures. Within 30 min after treatment with 32 .mu.g of phaseollin/ml, 99% of the cells were killed. Prior exposure to a low concentration of phaseollin (4 .mu.g/ml) did not significantly alter the sensitivity of the cultures to the higher concentrations (32 .mu.g/ml) of phaseollin. Exogenously added phaseollin (4 .mu./ml) had a half-life of approximately 4 h in cell suspension cultures of P. vulgaris. When 14C-labeled phaseollin was added to the cultures, 14C appeared in an ethyl acetate- and H2O-insoluble product(s) associated with cell debris. No 14C-labeled phaseollin-like compounds accumulated in significant quantities. Phaseollin was not produced by mung bean P. aureus tissue, but exogenous phaseollin disappeared from cell suspension cultures of this species. The ability to metabolize phaseollin may not be associated specifically with species that readily produce phaseollin.