More than 100,000 publications demonstrate that AGC kinases are important regulators of growth, metabolism, proliferation, cell divison, survival and apoptosis in mammalian systems. Mutation and/or dysregulation of these kinases contribute to the pathogenesis of many human diseases, including cancer and diabetes. Although AGC kinases are also present in plants, little is known about their functions. We demonstrated that the AGC kinase OXIDATIVE SIGNAL-INDUCIBLE 1 (OXI1/AGC2-1) regulate important developmental processes and defense responses in plants. The summary of recent progress also demonstrates that we are only beginning to understand the role of this kinase pathway in plants.