The U.K. strain of COVID-19 virus maybe 70% more transmissible than the previously reported types, though no enough evidence yet if it is more deadly. This led UK Prime Minster Boris Johnson to place tighter COVID-19 restrictions in London and southeastern England to contain the fast-spreading virus.

In early December 2020, a group of UK scientists gathered virtually to report the spread of pandemic coronavirus. Their discussions funneled into the increasing cases in Kent, a county in southeastern England, while the rest of the country was managing the spread of the virus. This led to investigations of viral genomes from the region, which showed that half of the cases in Kent were caused by a variant labeled as B.1.1.7, which is more skillful in transmitting between humans. 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 target genes. Further examination revealed that the two lines with the dark green fruit and purple roots exhibit high levels of carotenoid in the gene-edited plants.

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.

For more details, read the news article from the University of Tsukuba website and the research article in Scientific Reports.