Regulation of central metabolism by trehalose 6-phosphate

ISHIHARA H; ENCKE B; FIGUEROA CM; KRAUSE U; STITT M; FEIL R; HOEHNE M; LUNN JE

Córdoba

Congreso; LII Reunión Anual de la SAIB; 2016

SAIB

Trehalose 6-phosphate (Tre6P) is an important signalmetabolite linking plant carbon metabolism with growth and development. The Tre6P-sucrosenexus model postulates that Tre6P regulates sucrose levels within anappropriate range and vice versa. To testthis model, we investigated short-term metabolic responses to ethanol-inducedincreases in Tre6P levels in Arabidopsisthaliana plants expressing the Escherichiacoli Tre6P synthase. Increased Tre6P levels led to a transient drop insucrose content, post-translational activation of both nitrate reductase andphosphoenolpyruvate carboxylase, and increased levels of organic and aminoacids. Radio- (14CO2) and stable-isotope (13CO2)labelling experiments in plants with elevated Tre6P showed no changes in photoassimilateexport rates, but increased labelling of organic acids. These results suggestthat high Tre6P levels divert carbon away from sucrose by stimulating carbon fluxesinto organic acids to provide C-skeletons for amino acid synthesis andsimultaneously stimulate nitrate assimilation. These findings are consistentwith the Tre6P-sucrose nexus model and implicate Tre6P in regulating interactionsbetween carbon and nitrogen metabolism in plants.