Universität zu Köln

Pokhilko, Alexandra, Flis, Anna ORCID: 0000-0002-9142-1606, Sulpice, Ronan ORCID: 0000-0002-6113-9570, Stitt, Mark ORCID: 0000-0002-4900-1763 and Ebenhoeh, Oliver ORCID: 0000-0002-7229-7398 (2014). Adjustment of carbon fluxes to light conditions regulates the daily turnover of starch in plants: a computational model. Mol. Biosyst., 10 (3). S. 613 - 628. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 1742-2051

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Abstract

In the light, photosynthesis provides carbon for metabolism and growth. In the dark, plant growth depends on carbon reserves that were accumulated during previous light periods. Many plants accumulate part of their newly-fixed carbon as starch in their leaves in the day and remobilise it to support metabolism and growth at night. The daily rhythms of starch accumulation and degradation are dynamically adjusted to the changing light conditions such that starch is almost but not totally exhausted at dawn. This requires the allocation of a larger proportion of the newly fixed carbon to starch under low carbon conditions, and the use of information about the carbon status at the end of the light period and the length of the night to pace the rate of starch degradation. This regulation occurs in a circadian clock-dependent manner, through unknown mechanisms. We use mathematical modelling to explore possible diurnal mechanisms regulating the starch level. Our model combines the main reactions of carbon fixation, starch and sucrose synthesis, starch degradation and consumption of carbon by sink tissues. To describe the dynamic adjustment of starch to daily conditions, we introduce diurnal regulators of carbon fluxes, which modulate the activities of the key steps of starch metabolism. The sensing of the diurnal conditions is mediated in our model by the timer alpha and the dark sensor'' beta, which integrate daily information about the light conditions and time of the day through the circadian clock. Our data identify the beta subunit of SnRK1 kinase as a good candidate for the role of the dark-accumulated component b of our model. The developed novel approach for understanding starch kinetics through diurnal metabolic and circadian sensors allowed us to explain starch time-courses in plants and predict the kinetics of the proposed diurnal regulators under various genetic and environmental perturbations.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Pokhilko, Alexandra UNSPECIFIED UNSPECIFIED UNSPECIFIED Flis, Anna UNSPECIFIED orcid.org/0000-0002-9142-1606 UNSPECIFIED Sulpice, Ronan UNSPECIFIED orcid.org/0000-0002-6113-9570 UNSPECIFIED Stitt, Mark UNSPECIFIED orcid.org/0000-0002-4900-1763 UNSPECIFIED Ebenhoeh, Oliver UNSPECIFIED orcid.org/0000-0002-7229-7398 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-450833
DOI:	10.1039/c3mb70459a
Journal or Publication Title:	Mol. Biosyst.
Volume:	10
Number:	3
Page Range:	S. 613 - 628
Date:	2014
Publisher:	ROYAL SOC CHEMISTRY
Place of Publication:	CAMBRIDGE
ISSN:	1742-2051
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ADP-GLUCOSE PYROPHOSPHORYLASE; SUCROSE-PHOSPHATE SYNTHASE; CIRCADIAN CLOCK; NUMERICAL-SIMULATION; ARABIDOPSIS PLANTS; NITRATE REDUCTASE; METABOLISM; GROWTH; SNRK1; TRANSCRIPTION Multiple languages Biochemistry & Molecular Biology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/45083