Abstract
Rubisco and stroma-localized fluorescent proteins of chloroplasts are mobilized to the vacuole via RCBs by an ATG-dependent autophagic process. In this study, we analyzed factors that affect the RCB-creation. RCBs are accumulated in the vacuole when excised leaves are incubated in darkness and nutrient-free medium with concanamycin A. The addition of MS medium containing sucrose remarkably suppressed the RCB-creation. Sucrose was the main constituent which suppresses the RCB-creation in MS medium. The RCB-creation was also suppressed in the light, but the suppression was retarded by DCMU. The content of soluble sugars and starch increased in the light, but decreased in darkness. These results suggested that the sugar contents in leaves were the main factors that affect the RCB-creation. We also found that the light specifically suppressed the RCB-creation, but not the other autophagosome-creation. These results indicated the presence of mechanism which specifically controls the RCB-creation in autophagy.
