Fig. 3: OSCA1.1 is required for bacterial virulence.

a, Gene model of OSCA1.1 showing the positions of the two amino acid substitutions in the osca1-1 mutant. b, A boxplot representing disease index scores (0, no symptoms; 0.5 to 1.5, weak chlorosis; 2 to 3, strong chlorosis) from n = 40 each of osca1-1 or Col-0 leaves infected with Xcc^* from eight individual plants, at seven DPI. Statistical significance is determined by a two-sided unpaired t-test (osca1-1 versus Col-0, P = 1.72e-5). ***P < 0.001. c, A boxplot representing bacterial population density in n = 23 osca1-1 or n = 24 Col-0 leaves infected with Xcc^* from eight different plants, at seven DPI. CFU, colony-forming units. Statistical significance is determined by a two-sided unpaired t-test (osca1-1 versus Col-0, P = 0.0013). **P < 0.01. d, Representative Xcc^* inoculated osca1-1 and Col-0 leaves at nine DPI. e, Relative expression of OSCA1.1 in Col-0 leaves infiltrated with Xcc∆xopD^*dTALE#1 (dTALE#1) and Xcc∆xopD^*dTALE#2 (dTALE#2), relative to its expression in Xcc∆xopD^*vec2 (vector) infiltrated leaves, at one DPI. The expression of TUB2 is used as a control. Data are presented as mean values ± s.d. (error bars) from n = 3 independent biological replicates. Small circles, data points of individual biological replicates. Statistical significance is determined by a two-sided unpaired t-test (dTALE#1 versus vector, P = 0.021; dTALE#2 versus vector, P = 0.045). *P < 0.05. f,g, Microscopy images of the epidermal pavement cells and guard cells expressing OSCA1.1-GFP at the plasma membrane in Xcc∆xopD^*vec2 (vector) (f) and Xcc∆xopD^*dTALE#1 (dTALE#1) (g) inoculated leaves of the ProOSCA1.1:OSCA1.1-GFP transgenic line at five DPI. The effector-recipient cells are indicated with white triangles. The experiments were repeated twice independently with similar results. h, A boxplot representing bacterial population density in Col-0 leaves inoculated with Xcc∆xopD^* (−XopD) and Xcc^* (+XopD) strains that deliver empty vector (vector), dTALE#1 or dTALE#2, at seven DPI. For each bacterial strain, n = 12 infected leaves from four individual plants were examined. Differences between bacterial populations of all bacterial strains were not significant (one-way ANOVA test). i, Representative leaves used in (h). On the boxplots (b,c,h), horizontal lines from the top show maxima, upper quartile, median, lower quartile and minima values; cross marks show the mean values; and small circles show data points of individual biological replicates.

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