UDP-glycosyltransferases catalyze the addition of sugars to a wide range of small molecules thereby altering their activity, solubility and transport. In Arabidopsis, over 100 glycosyltransferase genes are annotated, however, only a limited number of these have been characterized. Arabidopsis UGT74E2 is an indole-3-butyric acid (IBA)-glycosyltransferase expressed in the root expansion zone and in the margins of leaf base and petioles. UGT74E2 transcripts are highly inducible by various biotic and abiotic stress conditions. Transgenic Arabidopsis plants overproducing UGT74E2 contain significantly higher levels of IBA-glucose and free IBA and show changes in plant architecture and enhanced drought tolerance. Taken together, the results indicate a role for UGT74E2-induced alterations in IBA homeostasis as an adaptation mechanism to environmentally adverse conditions. These results constitute one of the first steps in the largely unexplored field of auxin homeostasis during environmental stress. It is well-documented that ROS play a central role in responses to both abiotic and biotic stresses and ROS/hormonal homeostasis in plants. However, the molecular and biochemical mechanisms involved are poorly understood. The interaction of signals conferring crosstolerance and developmental traits and its influence on crop growth and yield is a priority in programs for improving plant stress tolerance. In this sense, Arabidopsis overexpressing UGT74E2 and T-DNA knockout lines are a valuable tool system. The transgenic plants will be investigated under different abiotic stresses. The analysis of the stress tolerance, levels of hormone and glycosyl-derivates, analysis of the UGT74E2 promoter and the transcriptional profiles of both transgenic and wild-type plants will provide valuable insights into novel stress-responsive genes involve in the crosstalk between hormone and ROS.