TY  - JOUR
A1  - Martins, Marina Camara Mattos
A1  - Hejazi, Mahdi
A1  - Fettke, Jörg
A1  - Steup, Martin
A1  - Feil, Regina
A1  - Krause, Ursula
A1  - Arrivault, Stephanie
A1  - Vosloh, Daniel
A1  - Figueroa, Carlos Maria
A1  - Ivakov, Alexander
A1  - Yadav, Umesh Prasad
A1  - Piques, Maria
A1  - Metzner, Daniela
A1  - Stitt, Mark
A1  - Lunn, John Edward
T1  - Feedback inhibition of starch degradation in arabidopsis leaves mediated by trehalose 6-phosphate
JF  - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants
N2  - Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by beta-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 mu M in the cytosol, 0.2 to 0.5 mu M in the chloroplasts, and 0.05 mu M in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night.
Y1  - 2013
U6  - https://doi.org/10.1104/pp.113.226787
SN  - 0032-0889
SN  - 1532-2548
VL  - 163
IS  - 3
SP  - 1142
EP  - 1163
PB  - American Society of Plant Physiologists
CY  - Rockville
ER  -