Plants also undergo evolution. Solve a 125 million year old mystery

Plant genomics has come a long way since its inception w Cold Spring Harbor Laboratory (CSHL) The first plant genome has been sequenced, but developing the perfect crop is still a 'game of chance'. It turns out that creating the same mutation in two different species does not always lead to the same effects. The question “why” remained unanswered for a long time.

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Using the examples of tomato and Arabidopsis plants, they can see that the key to this is the different regulatory systems used by the same gene, details of which are described in the journal PLOS Genetics.

Not all plants develop in the same way

Scientists have used genome editing to create more than 70 mutant species of tomato and Arabidopsis (Arabidopsis thaliana plant). Each mutation removed a piece of regulatory DNA around a gene known as CLV3. They then analyzed the effects of mutations on plant growth and development, and when the DNA that controls CLV3 mutated significantly, fruit growth exploded.

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Dr. Danielle Cerin from CSHL School of Biological Sciences:

CLV3 helps plants develop normally – without it they would look very different. All fruits will be huge and imperfect. You have to balance growth and return. If a plant has giant tomatoes but only two, is it as beneficial as having many but smaller tomatoes? There is no simple solution. You always sacrifice something when you try to improve something.

In tomato, mutations at the beginning of the CLV3 gene, but not at the end, greatly affect fruit size. In Arabidopsis, the parts surrounding both parts of the gene have been changed. This means that something happened over the past 125 million years that caused these plants to evolve differently. What exactly happened remains a mystery.

Dr. Danielle Sirin explains:

You cannot go back to a common ancestor because it no longer exists. Therefore it is difficult to say what the original condition was and how the genes were mixed. The simplest explanation is that there is a regulatory element that is more or less retained and has been changed in subtle ways.

Certainly, genetic organization is not the same in different plant species. Discovering these genetic differences could help make crop genome engineering more predictable. This would be a huge win, not only for science, but also for farmers and plant breeders around the world.