Mechanisms for Initial Plasma Membrane Responses in Proteinaceous Elicitor-induced Programmed Cell Death in Tobacco BY-2 Cells

Abstract

A proteinaceous elicitor from a pathogenic fungus, cryptogein, induced programmed cell death (PCD) in suspension-cultured tobacco (BY-2) cells. Changes in cell shape, cytoplasmic condensation as well as swelling and collapse of the vacuoles were observed during the PCD. Various plasma membrane ion fluxes such as Ca²⁺ influx, Cl^- efflux and H⁺ influx were induced within a few minutes after elicitation, suggesting that ion channel cascade play important roles in regulation of PCD. To elucidate the molecular mechanisms for the [Ca²⁺]_cyt changes, effects of various specific inhibitors were tested. Elicitor-induced production of reactive oxygen species (ROS) was shown to be regulated by ion fluxes including Ca²⁺ influx. Possible mechanisms and significance of ion fluxes and ROS production during the PCD will be discussed.