Sucrose deficiency delays lycopene accumulation in tomato fruit pericarp discs.
Tomato (Solanum lycopersicum) fruit ripening is characterized by a massive accumulation of carotenoids (mainly lycopene) as chloroplasts change to chromoplasts. To address the question of the role of sugars in controlling carotenoid accumulation, fruit pericarp discs (mature green fruits) were cultured in vitro in the presence of various sucrose concentrations. A significant difference in soluble sugar content was achieved depending on external sucrose availability. Sucrose limitation delayed and reduced lycopene and phytoene accumulation, with no significant effect on other carotenoids. Chlorophyll degradation and starch catabolism were not affected by variations of sucrose availability. The reduction of lycopene synthesis observed in sucrose-limited conditions was mediated through metabolic changes illustrated by reduced hexose accumulation levels. In addition, variations of sucrose availability modulated PSY1 gene expression. Taken together our results suggest that the modulation of carotenoid accumulation by sucrose availability occurs at the metabolic level and involves the differential regulation of genes involved in carotenoid biosynthesis.
Télef
Nadège
N
UMR Physiologie et Biotechnologie Végétales, INRA, Université Bordeaux 1, Université Victor Segalen Bordeaux 2, CR INRA de Bordeaux, 71 Avenue Edouard Bourleaux, BP 81, 33883, Villenave d'Ornon Cedex, France.
Stammitti-Bert
Linda
L
Mortain-Bertrand
Anne
A
Maucourt
Mickaël
M
Carde
Jean Pierre
JP
Rolin
Dominique
D
Gallusci
Philippe
P
D001483:Base Sequence; D002338:Carotenoids / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D018749:RNA, Plant / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013395:Sucrose / Q000378:metabolism*; D019207:beta Carotene / Q000378:metabolism
D017931:DNA Primers; D005030:Ethylenes; D018749:RNA, Plant; D019207:beta Carotene; D002338:Carotenoids; D013395:Sucrose; C036216:ethylene; D000077276:Lycopene