10
Sucrose and Starch Metabolism
Ce ́cile Vriet, Anne Edwards, Alison M. Smith,
and Trevor L. WangAbstract
The metabolism of starch and sucrose fuels all aspects of plant growth and
development. Over the last decade, significant advances have been made
in our understanding of the metabolism of these compounds through the
use of model systems, mainlyArabidopsis. Legume species are charac-
terised by their capacity to form symbioses withRhizobium, a nitrogen-
fixing bacterium, leading to up to half the carbon assimilated in
photosynthesis being sequestered to their roots. Study of a legume model
may therefore increase our knowledge about carbohydrate turnover. We
review here the resources available and the contribution that research on
Lotus japonicushas made to our knowledge of sucrose breakdown and
starch metabolism in relation to plant growth and development processes,
especially processes that are legume specific.10.1 Introduction
Plants are photoautotrophic organisms that cap-
ture energy from sunlight for the reduction of
carbon dioxide to generate sucrose. The sucrose
produced is exported from the source leaves to
non-photosynthetic parts of the plant, where it is
by far the major source of carbon for cellular
metabolism. Sucrose and its metabolites are also
important signalling molecules, influencing a
host of growth and developmental processes. As
well as producing sucrose for immediate use,
most plants also store some of their assimilated
carbon in the form of starch. Starch accumulated
in leaves during the day is broken down to pro-
vide a supply of carbon for metabolism during
the night. Starch accumulated in other organs of
the plant, including roots, stems and seeds, fuels
cellular metabolism at times when photosynthe-
sis is not possible, for example during regrowth
following defoliation and during germination.
Over the last decade, studies performed on the
model plantArabidopsis thalianahave greatly
improved our understanding of starch and
sucrose metabolism (see recent reviews by Smith
et al. 2005 ; Zeeman et al. 2010 ; Stitt and Zeeman
2012 ). However, a broad understanding of the
importance of these processes for plant growthC. Vriet
Laboratoire de Génétique et Biophysique des
Plantes, Aix-Marseille University, 13009 Marseille,
France
A. EdwardsA.M. SmithT.L. Wang (&)
Metabolic Biology, John Innes Centre, Norwich
Research Park, Colney, Norwich NR4 7UH, UK
e-mail: [email protected]
S. Tabata and J. Stougaard (eds.),The Lotus japonicus Genome, Compendium of Plant Genomes,
DOI 10.1007/978-3-662-44270-8_10,©Springer-Verlag Berlin Heidelberg 2014
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