Abiotic stress responses are affected in crk mutants.

(A and B) Treatment with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) for two hours (A) or methyl viologen (MV) for 48 hours (B) resulted in stronger impairment of photosynthesis in a subset of crk mutants compared to Col-0 wild type as shown by changes in the maximum quantum yield of primary photochemistry (φ_Po). Significant differences in relation to wild type are indicated (n = 12, bars represent SD; one-way ANOVA with post hoc Tukey HSD) *** P<0.001. The experiment was repeated three times with similar results. (C) Clustering of DCMU and MV experiments. Red and blue indicate increased or decreased response with respect to Col-0, respectively (average of alleles). Color intensity is proportional to a Benjamini-Hochberg false discovery rate (FDR) adjusted Z statistic, which takes the estimated means and their variation into account. Roughly, |Z|>2 corresponds to an FDR<5%, and |Z|<2.6 to an FDR<1%. Results were clustered using a complete linkage algorithm with 1-Pearson correlation as distance. (D) In several crk mutant lines exposure to O₃ resulted in elevated electrolyte leakage. Electrolyte leakage was measured at indicated time points after start of the O₃ exposure that lasted 6 h (350 ppb). Mean values ± SD from two independent experiments are presented (n = 12, one-way ANOVA with post hoc Tukey HSD). (E) Xanthine-Xanthine Oxidase (X+XO) infiltration induced different levels of electrolyte leakage in crk mutants compared to wild type (0.1 U ml^-1, 4 h). Mean values ± SD from three independent experiments are presented (n = 16, linear model with single-step p-value adjustment for multiple testing). (F) Treatment with ultraviolet-A (UV-A) and–B (UV-B) radiation led to increased electrolyte leakage in crks compared to wild type. Mean values ± SD from three independent experiments are presented (n = 12, one-way ANOVA with post hoc Tukey HSD). (G) Effect on NaCl on the germination crk seedlings at 6 days after stratification. Values represent mean of the ratio (germination percentage on 120 mM NaCl / percentage on control medium) for each line (n = 15, linear model, single-step p-value adjustment). Experiments were performed three times. Asterisks indicate statistically significant differences between crks and Col-0 (*P<0.05, **P<0.01 and ***P<0.001) (D-G). Error bars indicate ± SE (D, E and F). Relative electrolyte leakage was calculated as a ratio of the value measured at the indicated time and the total electrolyte leakage after freezing (D and E) or autoclaving the samples (F).