MEMBRANE RESPONSES INDUCED BY OLIGOGALACTURONIDES IN SUSPENSION-CULTURED TOBACCO CELLS

Treatment of suspension-cultured tobacco cells with alpha-1,4-D-oligogalacturonides induced a rapid and transient stimulation of K+ efflux concomitant with membrane depolarization, alkalinization of the incubation medium, acidification of the cytoplasm, and an influx of Ca2+. Only oligogalacturonides with a degree of polymerization (DP) higher than nine and lower than 16 were active. The dodecagalacturonide exhibited the greatest ability to induce K+ efflux. The similarity between the structural requirements of oligogalacturonides that induce these short-term membrane responses and the structural requirements of oligogalacturonides that induce more enduring physiological and morphogenetic responses, suggests that one or more of the oligogalacturonide-induced membrane effects generate secondary messages leading to the long-term responses.