2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Japanese scientists edited the genome of tomatoes in such a way that the plants lost their seeds and no longer needed pollination to reproduce. The results of the work were published in Scientific Reports.
Fertilization without pollination, or parthenocarp, resulting in seedless fruits, is in many cases a valuable trait of agricultural plants. Such fruits are better suited for industrial processing (for example, making pastes and sauces) and are more pleasant for many people to eat. In addition, plants reproduce vegetatively (for example, by shoots) and do not depend on pollinating bees, whose global population has been sharply declining in recent years (this problem is so serious that attempts are being made to solve it with the help of drones).
Parthenocarpic cultures can be formed by chance, they are also obtained by exposure to various physical and chemical influences with long-term subsequent selection. Several varieties of seedless tomatoes were developed in this way. Attempts have also been made to create parthenocarpous tomatoes by genetic engineering, but this approach is complex and lengthy.
To induce parthenocarp quickly and in a targeted manner, researchers at the Universities of Tokushima and Tsukuba used high-precision CRISPR / Cas9 genome editing technology to inactivate the IAA9 gene in tomatoes. This gene, suppressing the synthesis of the phytohormone auxin, prevents the formation of the fetus without preliminary pollination.
Turning it off resulted in seedless fruit in both the Micro-Tom model tomato and the commercial Ailsa Craig variety. The required change was observed in almost 100 percent of the plant's DNA and was well transmitted in the next parthenocarp generation. At the same time, a genome-wide study did not reveal any extraneous mutations in the genome. The only external difference between the obtained plants and the usual ones was a simpler leaf shape - a trait that is also controlled by auxin. The modification did not affect the growth rate and fruit size.
Fruit development of regular (top) and edited tomato
According to the head of the work Keishi Osakabe (Keishi Osakabe), scientists have not tasted the resulting fruits, but in theory, they should not taste different from usual. As the authors write, the technique they have developed is suitable for obtaining different varieties of seedless tomatoes and a number of other crops.
Whether the CRISPR / Cas9-edited tomatoes will appear on store shelves will depend on the opinion of the licensing organizations. Given the safety of this technology (it does not require the use of viral vectors and the introduction of transgenes into the plant DNA), the need for strict regulation may not arise. For example, in 2016, the USDA refused to complicate in any way the circulation of the first crop grown with CRISPR / Cas9 - mushrooms that do not darken in air.