Establishment of Agrobacterium-mediated genetic transformation and application of CRISPR/Cas9 genome-editing system to Brassica rapa var. rapa

Abstract

Background: Genome editing is essential for crop molecular breeding. However, gene editing in turnip (Brassica rapa var. rapa) have not been reported owing to the very low transformation efficiency. Results: In this study, we established a transformation procedure involving chemical-inducible activation of the BrrWUSa gene, which resulted in high transformation frequencies of turnip. Estradiol-inducible BrrWUSa transgenic plants were fertile and showed no obvious developmental defects. Furthermore, we used CRISPR/Cas9 gene-editing technology to edit BrrTCP4b and generated 20 BrrTCP4b-edited seedlings with an increase in leaf trichome number. Conclusion: The results demonstrate that BrrWUSa improves the regeneration efficiency in turnip. The transformation procedure represents a promising strategy to improve genetic transformation and for functional characterization of genes in turnip.