Biochemical, molecular, and genetic experiments have supported a
central role of sugars in the control of plantmetabolism, growth, and development
and have revealed interactions that integrate light, stress,
and hormone signaling (Rolland et al., 2002). As the major product of
photosynthesis in higher plants, sucrose is transported from leaf to
grain in rice (Cho et al., 2011). The formation, transport, and storage
of sucrose are necessary to support normal development of rice (Lim
et al., 2006). To maintain an optimal functioning photosynthetic system,
the synthesis of sucrose and starch needs to be subtly regulated (Stitt,
2004). The products can be stored as starch granules in chloroplast or
transported to where they are needed by sucrose transporter, or
assimilated.