Effects of exogenous glucose on carotenoid accumulation in tomato leaves.
To investigate the effect of carbohydrate on carotenoid accumulation in leaves, excised plants of tomato (Lycopersicum esculentum var. cerasiformae, wva 106) were supplied with glucose through the transpiration stream for 48 h. We report here that sugar accumulation in leaves led to a decrease of carotenoid content, which was related to the reduction of Chl. The decrease in carotenoid amount correlated with a sugar-induced repression of genes encoding enzymes of the carotenoid and of the Rohmer pathways. The lower 1-deoxy-D-xylulose-5-phosphate synthase transcript level probably leads to a decreased metabolic flux through the methylerythritol pathway and subsequently to a lower amount of substrate available for plastidic isoprenoid synthesis. Differences between responses of young (sink) and mature (source) leaves to carbohydrate accumulation are discussed.
Mortain-Bertrand
Anne
A
INRA, UMR 619, 71 Avenue Edouard Bourleaux, BP 8, F-33883 Bordeaux, France.
Stammitti
Linda
L
Telef
Nadège
N
Colardelle
Patrice
P
Brouquisse
Renaud
R
Rolin
Dominique
D
Gallusci
Philippe
P
D050260:Carbohydrate Metabolism / Q000187:drug effects; D002338:Carotenoids / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D018515:Plant Leaves / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014166:Transferases / Q000235:genetics / Q000378:metabolism
D002734:Chlorophyll; D002338:Carotenoids; D014166:Transferases; C109461:deoxyxylulose-5-phosphate synthase; D005947:Glucose