Effects of growth substances on non-induced and Botrytis cinerea culture filtrate-induced phaseollin production in Phaseolus vulgaris cell suspension cultures

Abstract

Suspension cultures of Phaseolus vulgaris produced the phytoalexin phaseollin in the absence of added inducers. The concentrations of plant growth substances in the culture medium affected growth of the cultures and the extent of phaseollin production, both in untreated cultures and in response to treatment with sterile culture filtrates from Botrytis cinerea. 2,4-Dichlorophenoxyacetic acid was inhibitory to induced production at concentrations of around 2 × 10 −6 m and above, whereas 1-naphthylacetic acid only inhibited significantly at 2 × 10 −4 m. Gibberellic acid and abscisic acid both stimulated non-induced production, abscisic acid also inhibiting growth of the cultures. High kinetin concentrations were inhibitory to non-induced production, but partially relieved inhibition of induction in culture filtrate-treated cells caused by growth in high concentrations of 2,4-dichlorophenoxyacetic acid. This increased response was associated with higher phenylalanine ammonia-lyase activity during the induction period than observed in cultures grown in low kinetin concentrations. However, as phenylalanine ammonia-lyase activity was often higher in control than in induced cultures, it is unlikely that this enzyme plays a regulatory rôle in phaseollin biosynthesis in this system.