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. 2021 May 7;72(16):5905–5918. doi: 10.1093/jxb/erab200

Fig. 4.

Fig. 4.

Intra- and extraplastid events of chloroplast dismantling during senescence and stress. Intraplastid events (left side) include the disassembly and cleavage of different thylakoid membrane proteins, catalysed by Deg1, Deg2, FtsH6, and HvPAP14 proteases, the proteolysis of Rubisco and other stroma proteins catalysed by CND41 and HvPAP14 proteases, and the cleavage of starch granules (SG) to small starch granules (SSG) and formation of small starch granule-like (SSGL) bodies. Extraplastid events (right side) include the different pathways for chloroplast degradation: senescence associated vacuoles (SAV) (a), chloroplast vesiculation (CV) (b), and chlorophagy (c). Three types of piecemeal chlorophagy are distinguished: ATG8-interacting protein 1-positive (ATI1 PS) body (c1), Rubisco containing bodies (RCB) (c2), and SSGL body (c3). ATI1 PS, RCB, and SSGL bodies are removed by macroautophagy, an ATG-dependent piecemeal chlorophagy through autophagosomes (blue double-membrane vesicle) marked by ATG8 (red circles). SAV and CV-containing vesicles (CCV) are degraded by microautophagy (ATG-independent pathways). αAMY, amylase; GS-GOGAT, glutamine synthetase–glutamate synthase.