Cell proliferation and cell growth are two central aspects of organ growth in every living organism and largely depend on environmental conditions and nutrient availability. The genetic control of these processes determine final organ size and have to be tightly regulated. One of the major regulatory pathways involved in organ growth is controlled by the Target of Rapamycin (TOR) kinase, which translates environmental and nutritional information into permissive or restrictive growth decisions. TOR has been shown to play a role in a wide range of cellular processes like transcription, translation, ribosome biogenesis, cell-cycle, cytoskeleton organization, autophagy and regulation (activation and repression) of distinct metabolic processes. Although many of the TOR-pathway genes including up and downstream regulators are highly conserved in the eukaryotic kingdom, little is known about TOR functions in plants. This project aims to map the constitution, function and regulation of the TOR kinase complex in corn, an important crop model plant, during organ growth and development. Knowledge on the molecular mechanisms and regulation of an important growth-regulatory protein complex will straighten the path for targeted engineering of the TOR kinase complex in order to promote crop yield in normal or stress conditions.