Biofortification of tomatoes with beta-carotene through targeted gene editing

Vitamin A deficiency is one of the most severe micronutrient-related health issues worldwide. Tomatoes, a widely cultivated crop for their adaptability, nutritional value, and lycopene content (a beta-carotene precursor), are ideal candidates for biofortification. In this study, CRISPR-mediated knockout mutants (cr-SlLCYe and cr-SlBCH) were generated to enhance the precursor supply to the β-carotene biosynthetic pathway and reduce its degradation. Carotenoids profiling showed that β-carotene levels in the mutants were 1.7 to 2.5-fold higher than in the wild-type, whereas lycopene levels remained unaltered without altering lycopene content. To evaluate potential trade-offs, the characteristics of the mutant fruits were comprehensively assessed, including appearance quality (color, firmness), nutritional quality (sugars, organic acids, vitamin C), and postharvest traits (shelf life, resistance to Botrytis cinerea). These results provide a new strategy for elevating β-carotene without compromising fruit quality and offer new insights into combating vitamin A deficiency through targeted tomato breeding programs.