Ser162-Dependent Inactivation of Overproduced Sucrose-Phosphate Synthase Protein of Maize Leaf in Transgenic Rice Plants

;To investigate the role of Ser162 in phosphorylationdependent regulation of maize sucrose-phosphate synthase (SPS) activities in rice, transgenic rice plants expressing wild-type or mutagenized maize SPS were produced. Our results indicate that Ser162 was responsible for overproduction-induced inactivation of SPS protein and for light/ dark modulation of this protein in vivo.