Scientists at Stanford University have been exploring ways to make critical crops better able to withstand the stresses of climate change. While many of these plants might naturally adapt over time, scientists worry that changes are happening too rapidly for nature to keep up. The researchers think a solution could be genetic circuits that “smart plants” can turn on and off in response to climate challenges.
Jennifer Brophy, an assistant professor of bioengineering and part of the Stanford team, explains gene circuits essentially work like a computer code with logic gates guiding the decision-making process. And much like an electrical circuit, they require a “switch” to turn them on or off.
The team tested the theory on tobacco plants using a type of gene sequence called “promoters” to turn root growth on and off. These promoters are only found in certain regions of the plant, meaning the desired genetic traits they trigger only affect specific regions of the plant. That differs from traditional GM crops that resist herbicides or pests using relatively simple, imprecise systems that cause all of their cells to express the genes necessary for the desired trait.
In this case, they used the gene circuits to specify which types of cells were expressing certain genes, allowing them to adjust the number of branches in the root system without changing the rest of the plant. Out of the eight circuits targeted, only half produced the desired changes to root growth. Still, they’ve demonstrated that they can indeed change the growth structure of a model organism and intend to apply the same tools to commercial crops.
Brophy says progress in engineering plant roots to optimize water and nutrient acquisition has been limited by our capacity to design and build genetic programs that function in a predictable manner. “The same sort of logic gates that control root branching could be used to, say, create a circuit that takes into account both the nitrogen and phosphorus concentrations in the soil, and then generates an output that is optimal for those conditions.”
The researchers are currently investigating the possibility of using their genetic circuits to manipulate root structure in sorghum to help it absorb water and perform photosynthesis more efficiently. Ideally, Brophy says the work will help ensure that we will have plant varieties that we can grow, even if the environmental conditions that we’re growing them in become less favorable. (Sources: Stanford Bio, Genetic Literacy Project)