Plastidic Isoprenoid Synthesis during Chloroplast Development

摘要: The chloroplast isoprenoid synthesis of very young leaves is supplied by the plastidic CO2 → pyruvate acetyl-coenzyme A (C3 C2) metabolism (D Schulze-Siebert, G Schultz [1987] Plant Physiol 84: 1233-1237) and occurs via mevalonate pathway. C3 C2 and/or pathway barley (Hordeum vulgare L.) seedlings changes from maximal activity at leaf base (containing developing chloroplasts with incomplete thylakoid stacking but a considerable rate photosynthetic CO2-fixation) almost to ineffectivity tip mature activity). ability import isopentenyl diphosphate extraplastidic space gradually increases substitute for loss endogenous intermediate supply (change autonomic division-of-labor stage). Fatty acid NaH14CO3 decreases in same manner as shown sections isolated these. Evidence has been obtained drastic decrease decarboxylase-dehydrogenase during development compared other anabolic pathways (synthesis aromatic amino branched chain acids). noncompetition acetate isotopic dilution studies indicates that both pyruvate-derived an acetate-derived compound are simultaneously needed form introductory intermediates pathway, presumably acetoacetyl-coenzyme A.