Chromoplast biogenesis and carotenoid accumulation

• Chromoplasts can be derived from both photosynthetic and non-photosynthetic plastids.
• A master switch gene that governs chromoplast differentiation has been identified.
• A number of metabolic and cellular processes appear crucial for chromoplast biogenesis.
• Chromoplasts as a metabolic sink enable great biosynthesis and high storage capacity.
• Chromoplast biogenesis is critical for massive carotenoid accumulation.

Chromoplasts are special organelles that possess superior ability to synthesize and store massive amounts of carotenoids. They are responsible for the distinctive colors found in fruits, flowers, and roots. Chromoplasts exhibit various morphologies and are derived from either pre-existing chloroplasts or other non-photosynthetic plastids such as proplastids, leucoplasts or amyloplasts. While little is known about the molecular mechanisms underlying chromoplast biogenesis, research progress along with proteomics study of chromoplast proteomes signifies various processes and factors important for chromoplast differentiation and development. Chromoplasts act as a metabolic sink that enables great biosynthesis and high storage capacity of carotenoids. The formation of chromoplasts enhances carotenoid metabolic sink strength and controls carotenoid accumulation in plants. The objective of this review is to provide an integrated view on our understanding of chromoplast biogenesis and carotenoid accumulation in plants.