Fig 5. OsMADS23 mediates ABA sensitivity and ABA-induced stomatal movement in rice.

(A) Seed germination of OsMADS23-overexpressing plants (OE13 and OE14) or osmads23-1 mutant (M1) compared to their corresponding wild type (Nip or Z11) on half-strength MS medium without or with ABA for 4 days, respectively. Scale bars, 2 cm. (B) Seed germination rates scored from day 1 to day 4 after stratification on medium supplemented without or with 1 μM ABA, respectively. Error bars indicate SD with biological triplicates (n = 3, each replicate containing 50 seeds). (C) Plant growth in half-strength MS medium without or with ABA for 4 days, respectively. Two-day-old seedlings were transferred on medium with or without ABA. Scale bars, 2 cm. (D) Decrease rate of shoot and root length in 1 μM ABA compared to mock on day 4. Error bars indicate SD with biological triplicates (n = 3, each replicate containing 20 plants). (E) ABA content in OsMADS23-overexpressing lines and osmads23 mutant, and their corresponding wild type after exposed to drought stress. Two-week-old plants were subjected to drought stress for 3 days, and leaves were collected for measurement of ABA content. Error bars indicate SD with biological triplicates (n = 3, each replicate containing 5 plants). (F) Percentages of completely open, partially open, and completely closed stomata in wild type (Nip) and OsMADS23-overexpressing plants under normal and ABA treatment conditions. Results represent means ± SD (n = 300) from 10 plants per genotype. Two-way ANOVA was performed, followed by Bonferroni’s post-hoc test. Scale bars, 10 μm. (G) Relative transcription levels of key genes involved in ABA-dependent stress response pathway in 2-week-old plants under drought conditions for 3 days. Error bars indicate SD with biological triplicates (n = 3, each replicate containing 3 plants). *p < 0.05, **p < 0.01 or ***p < 0.001 (Student’s t test). Three independent experiments were performed.