Creating a novel herbicide-tolerance OsALS allele using CRISPR/Cas9-mediated gene editing

Weeds and weedy rice plague commercial rice fields in many countries. Developing herbicide-tolerance rice is the most efficient strategy to control weed proliferation. CRISPR/Cas9-mediated gene editing, which generates small InDels and nucleotide substitutions at and around target sites using error-prone non-homologous end joining DNA repairing, has been widely adopted for generation of novel crop germplasm with a wide range of genetic variation in important agronomic traits. We created a novel herbicide-tolerance allele in rice by targeting the acetolactate synthase (OsALS) gene using CRISPR/Cas9-mediated gene editing. The novel allele (G628W) arose from a G-to-T transversion at position 1882 of OsALS and conferred a high level of herbicide tolerance. Transgene-free progeny carrying homozygous G628W allele were identified and showed agronomic performance similar to that of wild-type plants, suggesting that the G628W allele is a valuable resource for developing elite rice varieties with strong herbicide tolerance. To promote use of the G628W allele and to accelerate introgression and/or pyramiding of the G628W allele with other elite alleles, we developed a DNA marker for the G628W allele that accurately and robustly distinguished homozygous from heterozygous segregants. Our result further demonstrates the feasibility of CRISPR/Cas9-mediated gene editing in creating novel genetic variation for crop breeding. (C) 2020 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

The novel herbicide-tolerance allele (G628W) created in rice using CRISPR/Cas9-mediated gene editing proved to be valuable for developing elite rice varieties with strong herbicide tolerance. A DNA marker for the G628W allele was developed to accurately distinguish homozygous from heterozygous segregants, facilitating its use and introgression into elite alleles for crop breeding. This study further demonstrates the feasibility of CRISPR/Cas9-mediated gene editing in generating novel genetic variation for crop improvement.