Sucrose accumulation in the sugarcane stem: pathways and control points for transport and compartmentation

The accumulation of high concentrations of sucrose in the stem of sugarcane has been the subject of many studies. Although models have been constructed from the available information, many steps in the transport and accumulation pathway remain unknown. Recent advances in molecular approaches may elucidate some of these processes. Genes encoding proteins associated with sugar synthesis and storage will provide valuable tools. In particular, the use of techniques to localize the sites of expression of sugar transporters and metabolic enzymes will assist in defining possible routes of sugar movement. When combined with an analysis of metabolite concentrations and enzyme activities in cellular and subcellular compartments, these novel approaches will contribute to an integrated picture of stem function. Control points identified will provide useful tools for selection of efficient genotypes and targets for molecular manipulations.