The correct partitioning of carbohydrate resources in a plant is of critical importance to optimising its growth and reproduction.Sucrose and starch are the two main sources of carbohydrate available in non-photosynthetic cells.In legumes, carbohydrate partitioning is complicated by the root symbiosis with rhizobia.The symbiotic organ, the nodule, receives large amounts of sucrose from the plant and partitions it between the synthesis of starch and pathways that generate energy and substrates for nitrogen fixation.These processes require additional controls on carbohydrate economy of the plant that are not seen in non-legumes.We have examined these controls in the model legume, Lotus japonicus, using a series of mutants obtained from forward screens for starch content and targeted reverse genetics via our TILLING platform (http://revgenuk.jic.ac.uk).Examination of the phenotype of these mutants has revealed some features of carbon partitioning that are seen in all plants, some that are likely to be particular to legumes and some that are novel.