Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 2 de 2
Filter
Add more filters










Database
Language
Publication year range
1.
Plant Cell Physiol ; 59(11): 2188-2203, 2018 Nov 01.
Article in English | MEDLINE | ID: mdl-30239816

ABSTRACT

Tocopherols are non-polar compounds synthesized in the plastids, which function as major antioxidants of the plant cells and are essential in the human diet. Both the intermediates and final products of the tocopherol biosynthetic pathway must cross plastid membranes to reach their sites of action. So far, no protein with tocopherol binding activity has been reported in plants. Here, we demonstrated that the tomato SlTBP protein is targeted to chloroplasts and able to bind α-tocopherol. SlTBP-knockdown tomato plants exhibited reduced levels of tocopherol in both leaves and fruits. Several tocopherol deficiency phenotypes were apparent in the transgenic lines, such as alterations in photosynthetic parameters, dramatic distortion of thylakoid membranes and significant variations in the lipid profile. These results, along with the altered expression of genes related to photosynthesis, and tetrapyrrole, lipid, isoprenoid, inositol/phosphoinositide and redox metabolism, suggest that SlTBP may act in conducting tocopherol (or its biosynthetic intermediates) between the plastid compartments and/or at the interface between chloroplast and endoplasmic reticulum membranes, affecting interorganellar lipid metabolism.


Subject(s)
Carrier Proteins/metabolism , Plant Proteins/metabolism , Solanum lycopersicum/metabolism , alpha-Tocopherol/metabolism , Chloroplasts/metabolism , Endoplasmic Reticulum/metabolism , Gene Knockdown Techniques , Lipid Metabolism , Solanum lycopersicum/genetics , Phylogeny , Plant Proteins/genetics , Plastids/metabolism
2.
J Exp Bot ; 69(15): 3573-3586, 2018 06 27.
Article in English | MEDLINE | ID: mdl-29912373

ABSTRACT

Light signaling has long been reported to influence fruit biology, although the regulatory impact of fruit-localized photoreceptors on fruit development and metabolism remains unclear. Studies performed in phytochrome (PHY)-deficient tomato (Solanum lycopersicum) mutants suggest that SlPHYA, SlPHYB2, and to a lesser extent SlPHYB1 influence fruit development and ripening. By employing fruit-specific RNAi-mediated silencing of SlPHY genes, we demonstrated that fruit-localized SlPHYA and SlPHYB2 play contrasting roles in regulating plastid biogenesis and maturation in tomato. Our data revealed that fruit-localized SlPHYA, rather than SlPHYB1 or SlPHYB2, positively influences tomato plastid differentiation and division machinery via changes in both light and cytokinin signaling-related gene expression. Fruit-localized SlPHYA and SlPHYB2 were also shown to modulate sugar metabolism in early developing fruits via overlapping, yet distinct, mechanisms involving the co-ordinated transcriptional regulation of genes related to sink strength and starch biosynthesis. Fruit-specific SlPHY silencing also drastically altered the transcriptional profile of genes encoding light-repressor proteins and carotenoid-biosynthesis regulators, leading to reduced carotenoid biosynthesis during fruit ripening. Together, our data reveal the existence of an intricate PHY-hormonal interplay during fruit development and ripening, and provide conclusive evidence on the regulation of tomato quality by fruit-localized phytochromes.


Subject(s)
Carotenoids/metabolism , Light Signal Transduction/radiation effects , Phytochrome/metabolism , Solanum lycopersicum/physiology , Starch/metabolism , Cytokinins/metabolism , Fruit/genetics , Fruit/growth & development , Fruit/physiology , Fruit/radiation effects , Indoleacetic Acids/metabolism , Solanum lycopersicum/genetics , Solanum lycopersicum/growth & development , Solanum lycopersicum/radiation effects , Plant Growth Regulators/metabolism , Plastids/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...