Aluminum toxicity in acid soil is a major stress to plant growth. The primary target is in root-tips where the epidermal and outer cortex layers of cells in the root transition zone area are more sensitive to the toxic ions. This project used laser capture microdissection (LCM) technology to isolate these Al-sensitive cells. Tandem mass tag (TMT) proteomics was used to identify Al- induced proteomes. The information was used to determine functions of protein changes in response to Al toxicity in these Al-sensitive root cells.