Researchers from the University of Tsukuba designed a method using
Target activation-induced cytidine deaminase (Target-AID) base-editing
technology and CRISPR-Cas9 system to improve yield, shelf-life, nutrient
content, and disease resistance in tomatoes.

Using the combined method, the researchers tweaked simultaneously the
three genes associated with carotenoid accumulation in tomatoes. The
three genes selected are SlDDT1, SlDET1, and SlCYC-B which are
responsible for carotenoid accumulation, specifically lycopene. The
mutation was shown in 10 out of the 12 tomato lines in all three
targetgenes. Further examination revealed that the two lines with the
dark green fruit and purple roots exhibit high levels of carotenoid in
thegene-editedplants.

The results from the study showed a significant breakthrough from the
early transgenic varieties using single nucleotide changes in individual
tomato genes. This will allow tomato breeders to introduce multiple
advantageous gene changes into competitive commercial varieties of
tomatoes and skipping extensive crossbreed steps between generations.

Multiple gene substitution by Target-AID base-editing technology in
tomato | Scientific Reports (nature.com)
[www.nature.com]