Gene editing yields tomatoes that flower and ripen weeks earlier

Using a simple and powerful genetic method to tweak genes native to two popular varieties of tomato plants, a team at Cold Spring Harbor Laboratory (CSHL) has devised a rapid method to make them flower and produce ripe fruit more than 2 weeks faster than commercial breeders are currently able to do. 

This means more plantings per growing season and thus higher yield. In this case, it also means that the plant can be grown in latitudes more northerly than currently possible - an important attribute as the earth's climate warms.

"Our work is a compelling demonstration of the power of gene editing - CRISPR technology - to rapidly improve yield traits in crop breeding," says CSHL Associate Professor Zachary Lippman, who led the research. Applications can go far beyond the tomato family, he says, to include many major food crops like maize, soybean, and wheat that so much of the world depends upon.

Lippman clarifies that the technique his team publishes today in Nature Genetics is about more than simply increasing yield. "It's really about creating a genetic toolkit that enables growers and breeders in a single generation to tweak the timing of flower production and thus yield, to help adapt our best varieties to grow in parts of the world where they don't currently thrive."

This led the team to employ the gene-editing tool CRISPR to induce tiny mutations in the SP5G gene. The aim was to inactivate the gene entirely such that it did not generate any anti-florigen protein at all.

When this tweaked version of SP5G was introduced to popular roma and cherry tomato varieties, the plants flowered earlier, and thus made fruits that ripened earlier. Tweaking another anti-florigen gene that makes tomato plants grow in a dense, compact, shrub-like manner made the early-flowering varieties even more compact and early-yielding.