Creating a zero amylose barley with high soluble sugar content by genome editing

Abstract

Amylose biosynthesis is strictly associated with granule-bound starch synthase I (GBSSI) encoded by the Waxy gene. Mutagenesis of single bases in the Waxy gene, which induced by CRISPR/Cas9 genome editing, caused absence of intact GBSSI protein in grain of the edited line. Consequently, B-type granules disappeared. The amylose and amylopectin contents of waxy mutants were zero and 31.73%, while those in the wild type were 33.50% and 39.00%, respectively. The absence of waxy protein led to increase in soluble sugar content to 37.30% compared with only 10.0% in the wild type. Sucrose and β-glucan, were 39.16% and 35.40% higher in waxy mutants than in the wild type, respectively. Transcriptome analysis identi ed differences between the wild type and waxy mutants that could partly explain the reduction in amylose and amylopectin contents and the increase in soluble sugar, sucrose and β-glucan contents. This waxy our, which showed lower nal viscosity and setback, and higher breakdown, could provide more option for food processing. Key MessageThe new zero amylose barley was obtained via the CRISPR/Cas9 genome editing, showing higher soluble sugar content and lower nal viscosity and setback.