The sensory and functional properties of rice are predominantly associated with its amylose content. Granule-bound starch synthase (GBSS) encoded by the Waxy (Wx) gene determines the synthesis of amylose, while starch branching enzymes encoded by Sbe genes are involved in the formation of amylopectin. Some studies have demonstrated that Wx gene is the major controller of amylose content but there are one or more modifying genes affecting the amylose content. Three markers, microsatellite, Single – nucleotide – polymorphism (G/T SNP) in Wx gene and Single – nucleotide – polymorphism (T/C SNP) in Sbe1 gene, were tested for their association with amylose content using sixty-nine rice accessions from twenty countries. Of the three markers, two markers in Wx gene are significantly associated with amylose content. The combination of two markers in Wx gene (haplotypes) explained 83.8% of the variation in amylose content and discriminated the three market classes of glutinous, low, intermediate and high amylose content of rice from each other. And T/C SNP in Sbe1 locus was not a suitable marker for amylose content. Keywords: marker, amylose content, Waxy gene.
Progress in High-Amylose Cereal Crops through Inactivation of Starch Branching Enzymes
