Abstract
Autophagy is an evolutionarily conserved intracellular process for the vacuolar degradation of cytoplasmic components. We developed autophagy monitoring systems in planta and revealed that plants in which ATG (autophagy-related) genes are disrupted (atg mutants) are defective in autophagy. Phenotypic analysis of the atg mutants showed that autophagy defects in higher plants result in early senescence and excessive immunity-related programmed cell death (PCD), irrespective of nutrient conditions, but the mechanisms by which cell death occurred in the absence of autophagy were unclear.
We have now identified a conserved requirement for salicylic acid (SA) signaling in these processes in atg mutants and found that SA signaling can induce autophagy. In this symposium, we will present our latest data concerning the physiological role of autophagy during senescence and the innate immune response in plants, and speculate about possible mechanisms for the negative regulation of cell death by autophagy.