Abstract
Developing seeds offer a fine experimental system for study on sugar transport mechanism(s) in sink tissue from source tissue. The sugar transporters identified as being specific to the seed development may play a crucial role for flowering and grain development. The rice sucrose transporter OsSUT1 and the monosaccharide transporters OsMST1-3 have been previously characterized. To investigate sugar transport processes during flowering and in developing grains of rice, we newly characterized two clones OsSUT2 and OsMST5. From the lines of evidence, the OsSUT2 and OsMST5 play a role during the development at the early stage of the seed development, while the OsSUT1 plays a main role on sucrose uptake from seed apoplast during grain development.
