Figure 1.

The A109V Dominant Mutation in HT1 Causes Ozone Sensitivity and High Stomatal Conductance.

(A) Representative images of O₃-treated (350 ppb for 6 h) and control plants, taken 24 h after the beginning of exposure. Bar = 1 cm.

(B) Stomatal conductance of intact plants. n = 5 to 6 plants; asterisk denotes statistically significant difference between genotypes (Student’s t test, P < 0.05).

(C) Leaf fresh weight loss in 2 h. n = 3 to 5 plants; statistically significantly different groups are denoted with different letters (ANOVA with Tukey unequal N HSD post hoc test, P < 0.05).

(D) Ion leakage from O₃-treated (350 ppb for 6 h) and control (clean air [CA]) plants 10, 24, and 32 h after the beginning of O₃ exposure. O₃ exposure was repeated at least three times with similar results, and data are presented as mean ± sd (n = 4). O₃-treated suu (ht1-8D) and ProHT1:HT1(A109V) in Col-0 plants were statistically significantly different from the wild type in all time points (ANOVA with Tukey HSD post hoc test, P < 0.05).

(E) Map of HT1 protein. Kinase domain, locations of suu (ht1-8D) mutation, ATP binding site, and deletion in ht1-2 are indicated.