Figure 1.

Schematic of the three types of plant autophagy. (A) In macroautophagy, a cup-shaped phagophore is formed and closes into double-membrane autophagosomes while wrapping the cellular substances. The autophagosome is then delivered to the vacuole, fused with the tonoplast, and degraded in the vacuolar lumen. (B) In microautophagy, intracellular material directly enters the vacuole by vacuolar endocytosis and is degraded. (C) During mega-autophagy, the tonoplast permeabilizes and ruptures, releasing a large number of hydrolases into the cytoplasm, resulting in indiscriminate degradation of cytoplasmic materials.