Figure 4

The bak1 mutations reduced the immunity of Arabidopsis against Ab. (A) Quantification of lesion development. Conidial suspensions of Ab (1 × 10⁵ conidia/mL) were drop-inoculated onto true leaves of 4–5-week-old plants. At 4 dpi, lesion areas were measured and the relative values to Col-0 (WT plants) were calculated. The means and SDs were calculated from three independent experiments. The statistical significance of differences between means was determined by Tukey’s HSD test. Means not sharing the same letter are significantly different (P < 0.05). (B) The bak1–5 mutation did not reduce preinvasive resistance against Ab in the pen2 mutant. Aliquots of 5 μL of conidial suspension (1 × 10⁵ conidia/mL) of Ab were drop-inoculated onto leaves of 4–5-week-old plants of the tested mutants. At 12 hpi, the inoculated leaves were collected and stained with trypan blue, and then invasive hyphae were observed under light microscopy. At least 50 germinating conidia were counted in each experiment. The means and SDs were calculated from three independent experiments. Statistical analysis using two-tailed Student’s t tests showed no significant differences between pen2 and pen2 bak1–5 mutants. (C) Lesion development caused by Ab on two pen2 bak1 mutants. Conidial suspensions (1 × 10⁵ conidia/mL) of Ab were drop-inoculated onto mature leaves of 4–5-week-old plants. The photograph was taken at 4 dpi.