Biochemical Analysis of SBEIIb Mutant Rice Lines Generated through CRISPR/Cas-mediated Targeted Mutagenesis

Abstract

Knock out of the Starch branching Enzyme [SBE] encoding genes lead to increase in the Apparent Amylose Content in cereals. Reduced SBE activity decreases the frequency of branch points in the Amylopectin fraction, while increasing the Amylose Content [AC]. AC is positively correlated to the Resistant Starch [RS], which acts as dietary fibre leading to lowering Glycemic Index [GI]. Among the 4 Starch branching enzyme encoding genes, SBEIIb is exclusively expressed in Rice Endosperm. Therefore, in this study, the homozygous OsSBEIIb mutant lines of CO51 rice cultivar generated through CRISPR/cas9 were selected and biochemical analysis was carried out to determine the AC. Among the events studied, all the events showed a relatively increased AC as compared to the wild type. These findings highlight the need of identifying and developing rice genotypes with high RS and Amylose, which can be suitable for consumption by people suffering from diabetes, obesity, and other colon related illnesses.