Genome editing has emerged as a technology with the potential to revolutionize plant breeding. In a study published in Scientific Reports, researchers report on generating, in less than 10 months, Tomelo, a non-transgenic tomato variety resistant to the powdery mildew fungal pathogen using the CRISPR/Cas9 technology, which is based on the Cas9 DNA nuclease guided to a specific DNA target by a single guide RNA (sgRNA).
Once they successfully utilized the CRISPR/Cas9 technology to produce the new tomato variety, the researchers conducted disease resistance assays with the powdery mildew fungus Oidium neolycopersici. The results revealed that all the Tomelo plants were fully resistant to the pathogen, whereas all tested wild-type plants were susceptible. In addition, they found that the Tomelo plants were not only morphologically similar to the wild type, but they also produced harvested fruit weight similar to the wild type.
The researchers also used whole-genome sequencing to show that Tomelo does not carry any foreign DNA sequences but only carries a deletion that is indistinguishable from naturally occurring mutations. The researchers concluded that using their technique may enable mutations to be readily introduced into elite or locally adapted tomato varieties in less than a year with relatively minimal effort and investment. “We hope that plant varieties, such as Tomelo, are adopted worldwide with similar regulatory burden as traditionally bred varieties to meet the food demands of the growing world’s population and promote competitiveness of the agrobiotech sector by reducing chemical input,” wrote the authors.