Mutation of ERECTA homologous genes confers ideal plant architecture in Brassica napus.

Abstract

Varieties with a semi-dwarf compact plant architecture may increase yield per unit area in rapeseed (Brassica napus) by allowing high-density cultivation and mechanical harvesting while conferring lodging resistance. Mutation of ERECTA (ER), which encodes a receptor-like protein kinase, generates a compact and upright plant architecture in Arabidopsis thaliana; however, there have been no reports on the roles of the ER family (ERf) in B. napus. In this study, we used the CRISPR/Cas9 system to generate mutants in each of the two homoeologs of B. napus ERf members BnaER and ER-Like 1 (BnaERL1), and in the single BnaERL2 gene, resulting in the homozygous mutants BnaA09.er/BnaC08.er, BnaA06.erl1/BnaC03.erl1, and BnaA10.erl2. Under greenhouse conditions, BnaA09.er/BnaC08.er plants were shorter than the wild type, with a compact inflorescence and shorter siliques. In addition, BnaA09.er/BnaC08.er plants produced significantly more branches and total siliques than the wild type, with no significant changes in the number of ovules per silique or thousand-seed weight. Under field conditions, the BnaA09.er/BnaC08.er mutant plant showed a phenotype comparable to that under greenhouse conditions, but with a notable drop in thousand-seed weight. These results indicate that the BnaA09.er/BnaC08.er mutant offers a valuable germplasm resource for breeding rapeseed with ideal plant architecture.

Supplementary information: The online version contains supplementary material available at 10.1007/s42994-025-00217-4.