*2.10. MdSAP15 Overexpression Enhances Drought Tolerance in Transgenic Arabidopsis Plants*

To evaluate drought tolerance, we simultaneously germinated seeds of the "Col" and *MdSAP15*-overexpressing lines and grew the seedlings on MS plates for one week before transplanting them into soil for another three weeks of culture. Drought conditions were then imposed by withholding water. After 20 days of stress, all of the plants exhibited symptoms related to severe water loss, although those symptoms were milder for the OE transgenics than for the WT. When rehydration began (2 days of refreshment), most of the "Col" plants did not recover (Figure 8A), whereas the survival rate was significantly higher for the three transgenic lines (Figure 8B). These results again indicated that the overexpression of *MdSAP15* in *Arabidopsis* plants enhances their degree of drought tolerance.

**Figure 8.** Assessment of drought tolerance in "Col" and transgenic *Arabidopsis* plants. (**A**) Representative images of four-week-old plants; (**B**) Survival rates of WT and transgenic lines 2 days after rehydration began. Error bars represent SD based on three independent replicates. For (**B**), bars not labeled with same letters in each panel indicate values are significantly different at *p* < 0.05, based on one-way ANOVA and Duncan's tests.
