CRISPR/Cas9-mediated LhNAP mutagenesis extends flower longevity in lily

Flower longevity is an important trait determining the ornamental plant quality. NAM/ATAF1,2/CUC2 (NAC) transcription factors regulate leaf and petal senescence in several plants. To extend the longevity of lily flowers, in this study we used the CRISPR/Cas9 technology for the targeted mutagenesis of LhNAP encoding the NAC transcription factor in the Oriental hybrid lily (Lilium spp.) 'Acapulco'. Filament-derived calli were transformed with binary vectors containing guide RNA expression cassettes targeting one or two regions of LhNAP and the codon-optimized Cas9 for Oryza sativa driven by Zea mays ubiquitin promoter. Mutant lines harbouring biallelic mutations at the LhNAP locus exhibited clearly delayed tepal senescence and abscission compared to the wild-type plants. Overall, our results highlight the potential of LhNAP-targeted genome editing to produce lilies with extended flower longevity and reveal the crucial role of LhNAP in regulating tepal senescence and abscission in lilies.