chlorophyll-b and isopentenyl-pyrophosphate

Transgenic plants of Arabidopsis thaliana (L.) Heynh. (ecotype Columbia) expressing the antisense AtMECT gene, encoding 2- C-methyl- D-erythritol 4-phosphate cytidylyltransferase, were generated to elucidate the physiological role of the nonmevalonate pathway for production of ent-kaurene, the latter being the plastidic precursor of gibberellins. In transformed plants pigmentation and accumulation of ent-kaurene were reduced compared to wild-type plants. Fosmidomycin, an inhibitor of 1-deoxy- D-xylulose 5-phosphate reductoisomerase (DXR), caused a similar depletion of these compounds in transgenic plants. These observations suggest that both AtMECT and DXR are important in the synthesis of isopentenyl diphosphate and dimethylallyl diphosphate and that ent-kaurene is mainly produced through the nonmevalonate pathway in the plastid.

Topics: Aldose-Ketose Isomerases; Arabidopsis; Carotenoids; Chlorophyll; Chlorophyll A; Chloroplasts; Cloning, Molecular; Diterpenes; Diterpenes, Kaurane; DNA, Antisense; Fosfomycin; Hemiterpenes; Mevalonic Acid; Molecular Sequence Data; Multienzyme Complexes; Nucleotidyltransferases; Organophosphorus Compounds; Oxidoreductases; Phenotype; Pigments, Biological; Plants, Genetically Modified