A CRISPR/Cas9-induced male-sterile line facilitating easy hybrid production in polyploid rapeseed (Brassica napus)

Abstract

Rapeseed is a globally significant oilseed crop cultivated to meet the increasing demand for vegetable oil. In order to enhance yield and sustainability, breeders have adopted the development of rapeseed hybrids as a common strategy. However, current hybrid production systems in rapeseed have various limitations, necessitating the development of a simpler and more efficient approach. In this study, we propose a novel method involving the targeted disruption of Defective in Anther Dehiscence1 of Brassica napus (BnDAD1), an essential gene in the jasmonic acid biosynthesis pathway, using CRISPR/Cas9 technology, to create male-sterile lines. BnDAD1 was found to be dominantly expressed in the stamen of rapeseed flower buds. Disrupting BnDAD1 led to decreased levels of α-linolenic acid and jasmonate in the double mutants, resulting in defects in anther dehiscence and pollen maturation. By crossing the double mutant male-sterile lines with male-fertile lines, a two-line system was demonstrated, enabling the production of F₁ seeds. The male-sterile trait of the bndad1 double mutant lines was maintainable by applying exogenous methyl jasmonate and subsequently self-pollinating the flowers. This breakthrough holds promising potential for harnessing heterosis in rapeseed and offers a simpler and more efficient method for producing hybrid seeds.

Acknowledgements

This work was sponsored by the STI 2030 - Major Projects (2023ZD04008).

Author contributions

L.J. conceived the experiments. M.T., R.W., W.G., and S.X. performed the experiments. Y.Z., J.D., and X.Y. were involved in many discussions. M.T. and L.J. wrote the manuscript.

Data availability

Data are available in the figures of the article and its supplementary materials.

Conflict of interest statement

The authors declare no conflict of interest.

Supplementary data

Supplementary data are available at Horticulture Research online.

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