Figure 8.

PUB18 Is Epistatic to Exo70B1 in the ABA-Mediated Drought Stress Responses.

(A) Real-time qRT-PCR analysis to detect the transcripts levels of PUB18, PUB19, and Exo70B1 in wild-type and pub18 pub19 double, exo70b1 single, and pub18 pub19 exo70b1 triple mutant plants. ACT8 was used as an endogenous control gene to normalize the expression fold of PUB18, PUB19, and Exo70B1. Error bars represent ±se from three independent experiments.

(B) Growth morphologies of wild-type and pub18 pub19, exo70b1, and pub18 pub19 exo70b1 mutant plants under normal conditions. Seedlings were grown on half-strength Murashige and Skoog agar plates for 9 d, transplanted to individual pots, and grown for 4 weeks in a growth chamber at 22°C under long-day conditions (16 h light/8 h darkness).

(C) Stomatal movements of wild-type and pub18 pub19, exo70b1, and pub18 pub19 exo70b1 mutant plants in response to ABA (10 μM) and mannitol (0.4 M). ABA- and mannitol-mediated stomatal behaviors were monitored as described in Figure 7D. Images of stomata were captured using bright-field microscopy. At least 30 stomatal apertures in each epidermal strip were measured per replicate. Three replicates were performed for each experiment. Error bars represent ±se (n = 90, **P < 0.005, one-way ANOVA). Bars = 10 μm.