Generating waxy rice starch with target type of amylopectin fine structure and gelatinization temperature by waxy gene editing.

Waxy rice, which lacks amylose, is an important variant in rice, and its starches have been widely used. New waxy rice varieties generated via the CRISPR/Cas9 gene-editing system is described. Herein, four waxy rice starches with different physicochemical properties were successfully obtained by the CRISPR/Cas9 editing Waxy (Wx) gene. The results showed that the amylose content (AC) of wx mutant starches ranged from 0.26 to 1.78 %, and CZBwx1 starches had the best gel consistency and highest water solubility among all wx mutants. Mutations of Wx allele produced more short-chains (degree of chain polymerization (DP) 6-11), and less medium- and long-chains (DP12-70) than that of Wx, while the AC of Wx allele mutants was higher than the mutations of Wx allele. The gelatinization temperature (GT) of wx mutant starches was higher than that of wx mutant starches. Moreover, we found that the GT and amylopectin fine structure type of waxy rice starch did not change after Wx gene editing. Based on these findings, it is possible to produce waxy rice starch with different physicochemical properties, containing target GT and chain length distributions of amylopectin.