Figure 7.

Abscisic acid (ABA) hyposensitivity of onac096 mutants. (a) WT seedlings were grown in MS Phytoagar medium for 10 d under continuous light conditions at 28 °C, followed by incubation in MS liquid medium supplemented with 100 µM SA, 100 µM IAA, 100 µM GA, 100 µM MeJA, 10 mM ACC, or 100 µM ABA. Seedlings incubated in 0.5× MS liquid medium without phytohormones were used as a mock control. Total RNA was isolated from the leaves at 12 h after treatment. Asterisks indicate statistically significant differences between ABA treatment and the mock control, as determined by Student’s t-test (*p < 0.05). (b,c) Detached leaves of 3-week-old WT and onac096 plants (n096-1 and n096-2) were treated with 3 mM 3 mM MES buffer (pH 5.8) containing 3 µM ABA under continuous light conditions at 28 °C. Detached leaves incubated in 3 mM MES buffer (pH 5.8) without ABA were used as a mock control. (b) The ABA hyposensitive phenotype was observed at 0 and 5 days of treatment (DT). (c) Total chlorophyll contents in detached leaves of WT and onac096 plants were measured at 5 DT. (d–g) Total RNA was isolated from detached leaves of 3-week-old WT and onac096 plants under dark-induced senescence (d,e) or attached leaves of WT and ONAC096-OX plants grown in paddy soil for 3 weeks under LD conditions (f,g). (a,d–g) ONAC096 (a), OsABI5 (d,f), and OsEEL (e,g) transcript levels were measured by RT-qPCR and normalized to that of OsUBQ5. Relative expression was calculated using the ΔΔC_T method. Mean and SD values were obtained from three biological repeats. Asterisks indicate statistically significant differences between onac096 and ONAC096-OX plants compared to the WT, as determined by Student’s t-test (*p < 0.05 and **p < 0.01). The experiments were repeated twice with similar results. FW, fresh weight.