Stomatal closure responses to COR-deficient or wild-type bacteria. Stomatal apertures from leaf peels of Col-0, fls2, efr-1, and fls2 efr-1 plants treated with water or Pst DC3118 at 1E + 8 CFU/mL (A), Col-0 and Ws-0 plants treated with water or Pst DC3118 at 1E + 8 CFU/mL (B), and Col-0 and fls2 plants treated with water or Pst DC3000 at 1E + 8 CFU/mL (C). Results are displayed as means of 30 to 60 stomata, with ses indicated. Statistical differences between water and bacterial treatment are detected with two-tailed t test (***, P < 0.001). In all our experiments, to preserve the stomatal aperture status in plants used for both stomatal and bacterial pathogenesis assays, we did not further treat leaf peels in any stomatal opening buffer.