Crop Biotech Update

Study Shows How Nature Makes Solution to Hidden Mutations

May 8, 2019

Genetics professor Zachary Lippman, together with team, shared the result of their study on cryptic mutation and some vital lessons for gene editing in crops. Their study is published in Nature Plants.

The research is founded in the story of Campbell Soup Company and a field of tomatoes back in the mid-20th century. In the field of tomatoes, one plant had a surprising characteristic-the fruits separated from the vine right where the green cap and step touch the rest of the fruit. This jointless mutant plant was ideal for large-scale production because the other varieties would break away at a joint-like nub in the fruit stem, leaving pointed green caps that puncture other tomatoes in transit. The breeders called the gene mutation as jointless-2 (j2) and tried to introduce it into many varieties. However, doing so led to jointless tomato plants with excessive branching.

In 2017, Lippman and colleagues revealed that an ancient gene mutation interferes with j2 leading to a cryptic mutation. Now with the advent of gene editing techniques such as CRISPR, scientists can make fine adjustments in the mutations to prevent negative interactions that hinder agricultural production. Lippman also found that some breeders were able to neutralize negative interactions by duplicating the ancient mutation that interacts with j2. In other words, doubling the ancient mutation gives the same result as having no mutation at all.

"This [duplication event] was naturally occurring, so basically, nature provided the solution to its own problem," Lippman stressed.

Read more from Cold Spring Harbor Laboratory.