Gene editing technology improves tomato nutrition quality

Researchers led by the University of Tsukuba recently published a paper in Nature, demonstrating that Target-AID (target activation-induced cytidine deaminase) gene editing technology can be used to simultaneously introduce single-base changes into multiple genes in tomatoes. Using this technique, the researchers altered three genes (SlDDB1, SlDET1 and SlCYC-B) associated with carotenoid accumulation, resulting in elevated levels of tomato carotenoids, which are precursors to vitamin A and demonstrate antioxidant and anti-cancer properties. 

"The tomato was the first genetically modified food to be approved for human consumption," says senior author of the study Professor Hiroshi Ezura. "However, many early transgenic varieties contained genes derived from other species, raising safety concerns among consumers. Therefore, coupled with the fact that most transgenic varieties showed only moderate improvements in quality, tomato breeding has, for the most part, moved away from transgenics."

Unlike traditional genetic modification, modern gene editing techniques leave no trace in the genome and can introduce small changes within a native gene, mimicking natural variation.

In this paper, 10 our of 12 resulting tomato lines contained mutations in all three target genes. Further examination of two lines with the dark green fruit and purple roots of natural carotenoid accumulation mutants revealed high levels of carotenoids, particularly lycopene, in the gene-edited plants. 

This means the technology will allow tomato breeders to introduce multiple advantageous gene changes into elite commercial cultivars, bypassing lengthy back-crossing steps between generations. Besides, as Professor Ezura explains, "This shows that it is possible to improve multigenic plant quality traits using gene editing technology, and opens up a whole range of options for improving the yield, shelf-life, nutrient content, and disease resistance of different crop plants, which has obvious benefits for both human health and the environment."

References

Hunziker, Johan, et al. "Multiple gene substitution by Target-AID base-editing technology in tomato." Scientific Reports10.1 (2020): 1-12.

University of Tsukuba, http://www.tsukuba.ac.jp/en/research-list/p202012011400

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