Abstract: In S. cerevisiae, GYP can accelerate the intrinsic GTPase activity of YPT via the TBC active domain. In Arabidopsis, proteins containing similar TBC domain were called AtGAPs, but the biological function of AtGAPs, especially in stress response were not well known. There we isolated and characterized an Arabidposis T-DNA insertion mutant of RabGAP7. Phenotype analaysis suggested that the mutant was less sensitive to ABA and dehydration. Also it was found that the level of Rab7 and GPA1 on mRNA were lower in the wild-type than in rabgap7 plants by RT-PCR. So we conclude the RabGAP7 is involved the ABA response by activating the special G proteins.

Key words: Arabidopsis, Rab, RabGAP7, ABA