Abstract
Strawberry (Fragaria × ananassa Duch.) is an important fruit crop
worldwide. Mutation of Arabidopsis thaliana ROOTY (RTY)
results in increased endogenous auxin levels and root and shoot growth,
but the effects of this gene in strawberry remain unclear. Here, we
heterologously expressed Arabidopsis rty in strawberry plants and
examined the effects of rty expression on the hormonal and
physiological properties of the plants. Heterologous expression of rty
induced IAA accumulation and increased the production of adventitious
roots as well as trichomes on the abaxial leaf surface of the transgenic
plants. Furthermore, the transgenic strawberry plants had increased ABA
accumulation and stomatal closure. The transgenic strawberry plants
exhibited enhanced water use efficiency and a reduced water loss rate.
Additionally, peroxidase and catalase activities were significantly
higher in the transgenic plants than in the untransformed controls, and
the transgenic plants were more drought tolerant than the wild-type
plants. Our results suggest that transgenic approaches can be used to
overcome the inherent trade-off between plant growth and drought
tolerance by enhancing water use efficiency and reducing water loss rate
under water shortage conditions. This study provides the basis for
future genetic modifications of strawberry to improve drought tolerance.