Fig. 6: MREL57 destabilizes microtubules and positively regulates stomatal closure in response to ABA.

a Detached rosette leaves from Pro_MREL57:GUS transgenic seedlings were incubated in opening buffer for 2 h and then treated with or without 10 μM ABA for 2 h. The epidermal strips were peeled from the rosette leaves and GUS staining was performed. The experiment repeated three times with similar results. Scale bar = 10 μm. b MREL57 expression was detected by quantitative real-time RT-PCR in WT, mrel57-1, and mrel57-2 mutant seedlings. The experiment was repeated three times as different biological replicates. Error bars indicate standard deviation. c Fresh weights of detached leaves of seedlings from WT, mrel57-1, and mrel57-2 were measured every 30 min for a total of 3 h. The experiment was repeated three times with independent treatments. d Drought phenotypes in the wildtype, mrel57-1, and mrel57-2 in soil. Three-week-old seedlings were subjected to drought stress by withholding water for 2 weeks before being photographed. Values represent mean ± SD for three independent experiments. Two-tailed Student’s t test. **p < 0.01. e Infrared thermography of seedlings from WT, mrel57-1, and mrel57-2. Leaf temperature was measured using infrared camera software. The experiment was repeated three times with independent treatments. Error bars indicate standard deviation. Data represent mean ± standard deviation (SD) values. Different letters represent significant differences at p < 0.01 (one-way ANOVA). f Detached rosette leaves from WT, mrel57-1, and mrel57-2 were incubated in opening buffer for 2 h and then treated with 10 μM ABA with or without oryzalin. The box and whiskers plots represent minimum and maximum values. The line in the box indicates the median value and the boundaries demonstrate the 25th percentile (upper) and the 75th percentile (lower). Different letters represent significant differences at p < 0.01 (one-way ANOVA). The experiment was repeated three times as different biological replicates with a minimum of 100 stomatal pores. g Cortical microtubules in guard cells from WT and mrel57-1 seedlings treated with 5 μM oryzalin for the indicated times. Scale bar = 10 μm. The graph shows the densities of microtubules. Data represent mean ± standard deviation (SD) values from three independent experiments with a minimum of 15 cells each. h Cortical microtubules in guard cells from WT, mrel57-1 mutant, and mrel57-1wdl7-1 double mutant seedlings treated with 10 μM ABA for 40 min. Scale bar = 10 μm. The graph shows the densities of microtubules. Data represent mean ± standard deviation (SD) values from three independent experiments with a minimum of 15 cells each.