Sugar signalling

In all organisms, complex regulatory networks coordinate growth and development with metabolic status. Plants use photosynthesis to produce carbohydrates in green tissues and these are distributed via the phloem transport system throughout the plant. Sugar derived signals control the expression of a large number of genes in photosynthesis and metabolism, resulting in a balance between carbohydrate availability and use.

We use a genetic approach to study sugar signalling in Arabidopsis and have identified a large number of sugar response mutants that are being analysed in detail. Previously we established the close relation between sugar induction of starch biosynthesis and ABA signalling (Rook et al. 2001, Plant J. 26:421). We also identified the Impaired Sucrose Induction1 (ISI1) gene, a highly conserved plant-specific protein involved in regulating carbohydrate allocation in plants (Rook et al., 2006, Plant J. 46:1045). In higher plants ISI1 is expressed in the phloem of leaves following the sink-to-source transition. Understanding the mechanisms that regulate carbohydrate allocation in plants is important to improve crop productivity for both food and biomass production.