Figure 7.

PIR2 is a cell wall determinant of resistance to osmotin. The tolerance to tobacco osmotin of cells (○, □) and spheroplasts (•, ▪) of strain BWG7a transformed (□, ▪) or not (○, •) with PIR2 in YEp24 was determined by incubation in either YPD medium (for cells) or 0.8 M sorbitol (for spheroplasts) containing increasing concentrations of osmotin as indicated. After 1 hr at 30°C, cells and spheroplasts were diluted and plated. Illustrated is the percentage of viable counts relative to the controls without osmotin. Values are the average of at least two measurements.