The End: Senescence and Cell Death (With Yuan Zhong and Jared Taylor) - Plants, like animals, employ cell death as a normal and necessary part of life. Cell death occurs during developmental processes, including embryo and leaf development, vascular tissue development, and various reproductive processes. Pathogen infection can initiate the hypersensitive response, which can include a rapid cell death, and through which the plant wards off pathogens and / or removes pathogen-infected cells. In response to seasonal, age, stress or reproductive cues, senescence is initiated in leaves; leaf senescence involves macromolecular breakdown and nutrient export, and
culminates in cell death. Senescence and death are active processes that require de novo gene expression. Recently, the genetic programs that activate and limit these processes have been identified. This lecture describes our current understanding of the processes that initiate, regulate and carry out senescence and death. Posted January 11, 2012, revised by Vagner Benedito ( June 30, 2014.