Regulation of Vacuole-Mediated Programmed Cell Death During Innate Immunity and Reproductive Development in Plants

Abstract

Programmed cell death (PCD), organized destruction of cells, is essential in development, maintenance of cellular homeostasis, and innate immunity in multicellular organisms. In most angiosperms, development of male and female organs involves spatial and temporal regulation of PCD. The tapetum, the innermost layer of the anther, provides both nutrient and lipid components to developing microspores, and has been proposed to be degraded by PCD during the later stages of pollen maturation. Plants lack homologues of most apoptosis-related genes in animals and have evolved specific mechanisms for PCD. PCD is also a crucial event in plant immune responses against microbial infection that prevents the spread of pathogens. Recent live cell imaging techniques have revealed the dynamic features and significant roles of the vacuole during defense responses and PCD. Disintegration or collapse of the vacuolar membrane has been suggested to trigger the final step of PCD in several cell types. We here overview spatiotemporal dynamic changes of the vacuole triggered by signals from pathogens and comparatively discuss PCD during innate immunity and reproductive development in plants.