SS1 — Oryza sativa Japonica

Summary

OS06G0160700 (SS1/SSI) in rice (Oryza sativa Japonica) on chromosome 6 encodes a starch synthase with alpha-1,4-glucan glucosyltransferase (NDP-glucose donor) activity (EC 2.4.1.21), belonging to the GS/SS and Glyco_trans_1 families. The protein localizes to amyloplasts, chloroplast stroma, and plastids. SS1 is associated with starch and amylopectin anabolism, endosperm and seed development, auxin signaling, and protein synthesis. It has been linked to numerous grain traits including starch cool paste viscosity, gelatinization temperature, amylopectin and amylose content, floury endosperm, grain appearance, shape, width, weight, size, number, and yield per plant, as well as seed weight, protein content, leaf width and length, and cold tolerance. Studies of related genes in other species link the family to starch metabolism, biosynthesis, and altered starch composition with increased amylose and modified amylopectin structure.