Genes for plant autophagy: functions and interactions.

Autophagy, or self-consuming of cytoplasmic constituents in a lytic compartment, plays a crucial role in nutrient recycling, development, cell homeostasis, and defense against pathogens and toxic products. Autophagy in plant cells uses a conserved machinery of core Autophagy-related (Atg) proteins. Recently, research on plant autophagy has been expanding and other components interacting with the core Atg proteins are being revealed. In addition, growing evidence suggests that autophagy communicates with other cellular pathways such as the ubiquitin-proteasome system, protein secretory pathway, and endocytic pathway. An increase in our understanding of plant autophagy will undoubtedly help test the hypothesized functions of plant autophagy in programmed cell death, vacuole biogenesis, and responses to biotic, abiotic, and nutritional stresses. In this review, we summarize recent progress on these topics and suggest topics for future research, after inspecting common phenotypes of current Arabidopsis atg mutants.