Vacuolar autophagy is a macromolecule degradation pathway in
which cellular components are transported to the vacuole to recycle nutrients during
nutrient deficiency and senescence and to clear damaged molecules and
organelles during environmental stress. Autophagy therefore contributes to
plant survival and growth during adverse environmental conditions. A major outstanding
question is how autophagy is regulated under these diverse conditions. We have identified
regulatory factors in the activation of autophagy, including the negative
regulators TOR and RAPTOR, and have evidence that the TOR signaling pathway is
involved in activating autophagy in response to stress conditions in plants. We
are also analyzing potential selective autophagy pathways, in which substrates
for autophagy are recognized by receptor proteins and targeted for degradation.
Pathways under study include degradation of the endoplasmic reticulum during ER
stress and degradation of ribosomal RNA in a ribophagy-related process.