Abstract
Wild watermelon (Citrullus lanatus L.) inhabits in the Kalahari desert and possesses well-developed root system to absorb deep underground water resources. Proteomic study showed that Ran GTPase (CLRan) was induced by drought stress in the roots of this plant. Furthermore, Arabidopsis over-expressing CLRan1 showed enhanced root growth, suggesting that CLRan1 may function as a key regulator for root growth. To understand molecular mechanism of root growth stimulation by CLRan1, site-direct mutagenesis approaches were undertaken in this study. Transgenic Arabidopsis over-expressing the constitutive-active form of CLRan1 (G19V) showed enhanced root growth. In contrast, dominant-negative form of CLRan1 (T24N) inhibited root growth in the transgenic plants. These results suggest that CLRan1 may regulate root growth through switching of its activation status.
