Vacuoles are suggested to play crucial roles in plant defense-related cel death. During programmed cel death, previous live cel imaging studies have observed vacuoles to become simpler in structure and have implicated this simplification as a prelude to the vacuole’s rupture and consequent lysis of the plasma membrane. Here, we examined dynamics of the vacuole in cel cycle-synchronized tobacco BY-2 (Nicotiana tabacum L. cv. Bright Yel ow 2) cel s during cel death induced by application of culture filtrates of Erwinia carotovora. The filtrate induced death in about 90%of the cel s by 24 h. Prior to cel death, vacuole shape simplified and endoplasmic actin filaments disassembled;however, the vacuoles did not rupture until after plasma membrane integrity was lost. Instead offacilitating rupture, the simplification of vacuole structure might play a role in the retrieval of membrane components needed for defense-related cel death.