FIG. 3.

Analysis of the pae mutants. (A) Effect of the pae mutations on virulence. Sixteen chicory leaves were infected for each strain. After incubation at 30°C for 24 h, the length of rotted tissue was measured to estimate the disease severity. Distribution of the extent of maceration is represented, each point corresponding to one leaf. Comparison of the distribution obtained for each strain by the statistical chi-square test indicates a significant difference between pairs of strains, except between the paeX mutant and the wild-type strain. This experiment was repeated three times, and the different experiments gave similar results. (B) Growth of E. chrysanthemi pae mutants on pectin. The E. chrysanthemi strains 3937, A4027 (paeY), A4029 (paeX), and A4030 (paeX paeY) were grown in M63 minimal medium supplemented with 0.4% sugar beet pectin (degree of acetylation, 23%). Cell density was estimated by measurement of the optical density at 600 nm.