CRISPR/Cas9-Mediated Mutagenesis in Tomato Targeting the DE-ETIOLATED1 Gene
Author(s)
Date Issued
April 1, 2026
Type
article
Volume
12
Issue
4
ISSN
2311-7524
Journal
Abstract
Tomato high pigment-2 (hp-2dg, hp-2, and hp-2j) mutant lines are characterized by mutations
in the DE-ETIOLATED1 (SlDET1; Solyc01g056340) gene. SlDET1 is responsible for
encoding a nuclear protein that acts as a negative regulator involved in light signaling,
repressing photomorphogenesis. These tomato mutant lines are known for increased levels
of antioxidant pigments in fruits, such as flavonoids and carotenoids, compared to the
wild-type fruits. In this study, CRISPR/Cas9, followed by the non-homologous end joining
mechanism of repair (NHEJ), was used to target the SlDET1 gene and investigate whether
the effects of these mutations could mimic the effects of hp-2 mutant lines, improving the
nutritional features of tomato fruits. Our results indicated that mutations generated by
CRISPR/Cas9 NHEJ in the hp-2 and hp-2j regions (exon 11) resulted in significant changes
in the SlDET1 coding and protein sequences. These mutations caused a low survival
rate of edited sprouts and regenerated plants with a very compromised capacity of allelic
heritability of these mutations for the following generations. However, regenerated plants
containing these site-specific mutations in the SlDET1 gene showed higher levels of phytochemicals
in ripe fruits. Furthermore, these edited plants also showed an upregulation of
structural genes involved in the synthesis of these biocompounds. Although the SlDET1
gene could be considered an interesting target gene for the nutritional improvement of
tomato fruits, our results showed that mutations within its exon 11 are quite critical and
can induce severe perturbations in plant physiology, with a compromised possibility to
develop new stable edited lines.
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