Chloroplast to chromoplast transition in tomato fruit: spectral confocalmicroscopy analyses of carotenoids and chlorophylls in isolated plastids and time-lapse recording on intact live tissue

摘要

During evolution, chromoplasts have emerged as plastid structures which accumulate pigments to facilitate flower pollination and seed dispersal of fleshy fruit. There is good evidence that chromoplasts derive from chloroplasts (Pyke, 2007), even if nobody has ever recorded this transition. Structural changes occurring during chloroplast to chromoplast transition have been described in fleshy fruit by electron microscopy primarily in tomato (Rosso, 1968; Harris and Spurr, 1969) and in bell pepper (Spurr and Harris, 1968). During the differentiation process controlled breakdown of chlorophyll and disruption of the thylakoid membrane occurred, concomitant with an increase in the aggregation of carotenoids. Different carotenoid-accumulating bodies have been described, including plastoglobules, crystalline and microfibrillar structures, and internal membranous structures.ud