Upon stress, increased reactive oxygen species (ROS) production affects auxin homeostasis and can lead to a reorientation of growth as part of Stress Induced Morphogenetic Responses (SIMR). Altered growth patterns include more compact growth and increased lateral growth. Basically, SIMR are strongly influenced by reciprocal interaction between ROS and auxin. ROS accumulation upon stress can change the apoplast and cytoplasm PH that directly affect auxin transport, or can alter PIN auxin transporters transcription, levels, intracellular trafficking, or polarity. The precise mechanism by which ROS alter auxin distribution and transport is poorly understood. The aim of this Master project is to study the effect of different stressors on auxin transporters expression and level by cell biology approaches.