Autophagy of whole and partial chloroplasts in individually darkened leaves: a unique system in plants?

Chloroplasts are the characteristic organelle of photoautotrophs. To acquire carbohydrates, the majority of leaf nitrogen is distributed to chloroplasts as photosynthetic proteins. During age-related senescence or under starvation conditions, chloroplasts become a major source of carbon and nitrogen for recycling. While bulk degradation of the cytosol and organelles must occur by autophagy in plants, the role of autophagy in chloroplast degradation is still unclear. Our recent results confirm the role of autophagy in both partial and whole chloroplast degradation, at least during promoted senescence of individually-darkened leaves.