Dae-Jin Yun, Division of Applied Life Science (Brain Korea 21 program), Gyeongsang National University, South Korea. Adaptation to environmental stresses is critical for determining plant growth and productivity. Plant responses to environmental stresses are governed by complex molecular and biochemical signal transduction processes, which coordinately act to determine tolerance or sensitivity at the whole-plant level. To understand plant stress adaptation, genes that are required for stress tolerance have been isolated in our lab. Selected from the repertoire of genes studied, I will present work on the biological functions of several key stress defense protein players: Gigantea (GI), YUCCA6, and a WD40-repeat protein (HOS15).