13 結果
The typically intense carotenoid accumulation in cultivated orange-rooted carrots (Daucus carota) is determined by a high protein abundance of the rate-limiting enzyme for carotenoid biosynthesis, phytoene synthase (PSY), as compared with white-rooted cultivars. However, in contrast to other
Linseed flax (Linum usitatissimum L.) is an industrially important oil crop, which includes large amounts of alpha-linolenic acid (18:3) and lignan in its seed oil. We report here the metabolic engineering of flax plants to increase carotenoid amount in seeds. Agrobacterium-mediated transformation
The xanthophylls are oxygenated carotenoids and are important structural components of the photosynthetic apparatus. Xanthophylls contribute to the assembly and stability of light-harvesting complex apoproteins (LHC) and contribute to photoprotection via non-photochemical quenching of chlorophyll
Carotenoids represent a group of widely distributed pigments derived from the general isoprenoid biosynthetic pathway that possess diverse functions in plant primary and secondary metabolism. Modification of alpha- and beta-carotene backbones depends in part on ring hydroxylation. Two
Carotenoid turnover was investigated in mature leaves of Arabidopsis (Arabidopsis thaliana) by 14CO2 pulse-chase labeling under control-light (CL; 130 micromol photons m(-2) s(-1)) and high-light (HL; 1,000 micromol photons m(-2) s(-1)) conditions. Following a 30-min 14CO2 administration,
The first dedicated step in plant xanthophyll biosynthesis is carotenoid hydroxylation. In Arabidopsis thaliana, this reaction is performed by both heme (LUT1 and LUT5) and non-heme (CHY1 and CHY2) hydroxylases. No mutant completely abolishing alpha- or beta-carotene hydroxylation has been described
To gain insight into the evolution of xanthophyll synthesis in Arabidopsis thaliana, we analyzed two pairs of duplicated carotenoid hydroxylase enzymes in Arabidopsis thaliana: the cytochrome P450 enzymes CYP97A3 and CYP97C1, and non-heme di-iron enzymes, BCH1 and BCH2. Hydroxylated carotenes did
Plants protect themselves from excess absorbed light energy through thermal dissipation, which is measured as nonphotochemical quenching of chlorophyll fluorescence (NPQ). The major component of NPQ, qE, is induced by high transthylakoid DeltapH in excess light and depends on the xanthophyll cycle,
BACKGROUND
Xanthophylls are oxygenated carotenoids playing an essential role as structural components of the photosynthetic apparatus. Xanthophylls contribute to the assembly and stability of light-harvesting complex, to light absorbance and to photoprotection. The first step in xanthophyll
Phytoene synthase catalyzes the dimerization of two molecules of geranylgeranyl pyrophosphate to phytoene and has been shown to be rate limiting for the synthesis of carotenoids. To elucidate if the capacity to produce phytoene is limiting also in the seed of Arabidopsis (Wassilewskija), a gene
Carotenoids with cyclic end groups are essential components of the photosynthetic membranes in all plants, algae, and cyanobacteria. These lipid-soluble compounds protect against photooxidation, harvest light for photosynthesis, and dissipate excess light energy absorbed by the antenna pigments. The
Lutein, a dihydroxy xanthophyll, is the most abundant carotenoid in plant photosynthetic tissues and plays crucial structural and functional roles in the light-harvesting complexes. Carotenoid beta-and epsilon-hydroxylases catalyze the formation of lutein from alpha-carotene (beta,epsilon-carotene).
Lutein, a dihydroxy derivative of alpha-carotene (beta,epsilon-carotene), is the most abundant carotenoid in photosynthetic plant tissues where it plays important roles in light-harvesting complex-II structure and function. The synthesis of lutein from lycopene requires at least four distinct