Sucrose transport from source to sink seeds in rice

In many higher plants, sucrose is loaded as a major carbon photoassimiliate into the phloem apoplastically by sucrose transporters (SUTs) and unloaded in sink tissues, where it serves as a storage material, carbohydrate backbone, and energy source. In sink tissues, a proportion of sucrose molecules are converted by cell wall invertases (CINs) into hexose that is imported into cells by monosaccharide transporters (MSTs). Thus, in developing seeds, co-ordinated regulation of SUTs, CINs, and MSTs is crucial in carbon distribution. Here, we summarize current efforts on the identification of SUTs, CINs, and MSTs in rice.