Synthetic genes to help plants cope with climate change

Aug. 12 () –

By using synthetic genes, researchers at Stanford University They have managed to modify the structures of the roots of plants.

This could allow crops to be more efficient at harvesting nutrients and water, and more resilient to the increasing pressures of climate change, as published in the magazine ‘Science’.

The researchers argued that global food production is increasingly threatened by the effects of climate change. As floods, droughts and extreme heat waves become more frequent, crops have to be able to adapt faster than ever. So they went to work manipulating the biological processes of plants to help them grow more efficiently and effectively under various conditions.

Jennifer Brophy, associate professor of bioengineering, and her colleagues have designed a series of synthetic genetic circuits that allow control of the decisions made by different types of plant cells.

They used these tools to grow plants with modified root structures. Their work is the first step in designing crops more capable of harvesting water and nutrients from the soil and provides a framework for designing, testing and improving synthetic genetic circuitry for other plant applications.

“Our synthetic genetic circuits are going to allow us to build very specific root systems or very specific foliar structures to see what is optimal for the difficult environmental conditions that we know are coming,” says Brophy. it’s a statement–. We are making plant engineering much more precise.”

Current genetically modified crop varieties use relatively simple and imprecise systems that make all their cells express the genes needed to, for example, resist herbicides or pests.

To achieve fine-grained control of plant behavior, Brophy and his colleagues built synthetic DNA that essentially works like computer code with logic gates that guide the decision-making process. In this case, they used those logic gates to specify which cell types expressed which genes, which allowed them to adjust the number of branches of the root system without changing the rest of the plant.

The depth and shape of a plant’s root system influence its effectiveness in extracting different resources from the soil. A shallow root system with many branches, for example, is better at absorbing phosphorus (which stays near the surface), while a deeper root system that branches off at the bottom is better at picking up water and nitrogen.

With these synthetic genetic circuits, the researchers could grow and test various root designs to create the most efficient crops for different circumstances. Or, in the future, they could give plants the ability to optimize themselves.

“We have modern varieties of crops that have lost their ability to respond to where the nutrients are in the soil,” says José Dinneny, an associate professor of biology in the College of Humanities and Sciences and one of the lead authors of the paper. type of logic gates that control root branching could be used, for example, to create a circuit that takes into account the concentrations of nitrogen and phosphorus in the soil, and then generate an output that is optimal for those conditions.”

Brophy designed more than 1,000 potential circuits to be able to manipulate gene expression in plants. He tested them on the leaves of tobacco plants, to see if he could get the cells in the leaves to create a glow-in-the-dark protein found in jellyfish. He found 188 working designs, which the researchers are uploading to a synthetic DNA database so that other scientists can use them in their work.

Once they had the designs that worked, the researchers used one of the circuits to create logic gates that would modify the expression of a specific developmental gene in a type of root cell from Arabidopsis thaliana, a small plant commonly used as a model organism. By changing the expression level of that gene, they were able to modify the density of the branches in the root system.

Now that they have shown they can change the growth structure of a model organism, the researchers aim to apply these same tools to commercial crops. They are investigating the possibility of using their genetic circuitry to manipulate the structure of the roots of sorghum, a plant that can be turned into biofuel, to help it absorb water and perform photosynthesis more efficiently.

“Climate change is altering the agricultural conditions in which we grow the plants we depend on for food, fuel, fiber and raw materials for medicines,” Brophy says. “If we are not able to produce those plants at scale, we we will face many problems. This work aims to help ensure that we have varieties of plants that we can grow, even if the environmental conditions in which we grow them become less favourable,” stands out.