Department of Plant Sciences

Iron (Fe) is an essential mineral for plant growth and development. It plays crucial roles in many fundamental processes in cells, such as respiration, photosynthesis. In plant cells, iron is compartmentalized into different organelles, such as chloroplasts, mitochondria and vacuoles for its synthetic functions or storage. Chloroplast, a photosynthetic apparatus, represents one of the organelles possessing the most iron-enriched biochemical reaction systems (photosystem I, photosystem II, cytochrome b6-f complex and ferredoxin) in the plant cell. However, little is to known about the iron metabolism in this organelle.

The ATP-dependent Clp protease is widely distributed in bacteria, cyanobacteria, mitochondria and chloroplasts and plays an important role in protein import to chloroplast (literature). In plants, the ATP-dependent Clp protease in chloroplasts is encoded by a nucleus gene ClpC. It is imported into chloroplast and functions in control of chlorophyll b synthesis (Nakagawara et al., 2007). Here, we show that CipC is involved in the iron homeostasis in mesophyll cells. Lesion of ClpC caused leaf chlorosis and growth inhibition, and this phenotype can be rescued by supplying iron. Expression profile analysis showed that the lesion of ClpC significantly increased the expression of AtFRO8 in the leaf, indicating that ClpC might be indirectly involved in the control of the expression of AtFRO8, consequently effect on iron homeostasis in chloroplasts.