The knockout of Gγ subunit HvGS3 by CRISPR/Cas9 gene editing improves the lodging resistance of barley through dwarfing and stem strengthening.

Abstract

Gγ subunits participate in multiple biological processes, but their biological function in barley is unknown. Here, CRISPR/Cas9 gene editing was used to knockout HvGS3 in barley. The height of hvgs3 plants were reduced by 37.8 ~ 43.1% compared to wild type, and the culm lodging resistance index (CLRI) of the second internode of stems was increased by 76.6%. The decrease in cell length of the second internode was similar to its node length. The shorter cells may be the main reason for the declines in the internode length and plant height. The number and area of vascular bundles, the epidermal thickness, and the mechanical tissue thickness were significantly higher in hvgs3 due to the higher lignin content. Transcriptome analysis showed higher expression of structural genes related to lignin biosynthesis. Gibberellin (GA) biosynthesis was suppressed through the down-regulation of the GA3ox gene, and the application of gibberellin restored the plant height of hvgs3, indicating that plant height was altered by hindering gibberellin biosynthesis. These results shed new light on the functions of the Gγ subunit GS3 and provide a resource for breeding new lodging-resistant barley cultivars.