GROWTH-CHARACTERISTICS AND ELICITOR-INDUCED REACTIONS OF PHOTOSYNTHETICALLY ACTIVE AND HETEROTROPHIC CELL-SUSPENSION CULTURES OF LYCOPERSICON-PERUVIANUM (MILL)

Cell suspension cultures of Lycopersicon peruvianum (Solanaceae) were established as well-growing photoautotrophic, photomixotrophic and heterotrophic cultures and their growth parameters were characterized. Elicitor-induced responses of these cultures to the tomato pathogen Fusarium oxysporum f. sp. lycopersici were investigated after treatment of cells with autoclaved mycelium and culture filtrate of this fungus. The dominant reaction was an enhanced incorporation of phenolic constituents in the plant cell wall. Among the nine phenolics released by alkaline hydrolysis the most prominent compounds were p-hydroxybenzaldehyde, vanillin, p-coumaroyltryamine, feruloyltyramine, p-coumaric acid and ferulic acid. Phenolic incorporation in cell walls resulted in increased stability of cells against protoplasting with microbial enzymes. Chlorogenic acid, as the main soluble phenolic compound, showed differential accumulation in the three cell cultures lines as well as an elicitor-induced transient decrease. In heterotrophic cells decrease of chlorogenate occurred concomitant with accumulation of caffeoyl- and p-coumaroylshikimate as well as increased activities of p-coumaroyl-coenzyme A: shikimic acid p-coumaroyltransferase. Upon elicitation increased activities of phenylalanine ammonia lyase and changes in peroxidase activities were also detected. Sesquiterpenoid phytoalexines were not produced by either one of the cell culture lines and levels of tomatine were not significantly affected by elicitation.