Plants occupy a unique nexus when it comes to climate change. On the one hand, they can help prevent climate change by capturing carbon. On the other, the cultivation of plants – better known as agriculture – has a large carbon footprint. The changing climate is also going to drastically shift where we can and should grow food. Fortunately, a precise gene editing tool known as CRISPR has the potential to shrink agriculture’s climate emissions and prepare crops for climate change.
Here are five ways CRISPR can be used to engineer hardier crops that fix more carbon and help to reduce greenhouse gas emissions related to agriculture.
1. Engineering more robust crops to persist in unfavorable environments
Climate change will shift the landscape of what we now consider arable land. Some regions that previously had short growing seasons will likely become more amenable to farming. But other regions where crops are now grown successfully will become too hot, too dry, or too salty.
These changes present two main options for how to feed ourselves. We can convert more native land to farmland through deforestation or the draining of wetlands, compounding the problem. Or we can choose the much better option and engineer plants that can handle harsher conditions.
Scientists are already demonstrating how CRISPR can engineer plants that are heat tolerant, drought tolerant and salt tolerant.
2. Engineering nitrogen fixation to end dependence on added fertilizers
Our dependence on added fertilizers can exacerbate the effects of climate change in two ways. First, the Haber-Bosch process, which is used to generate synthetic nitrogen fertilizers, relies on fossil fuels. Conversely, leaching of excess nitrogen pollutes waterways and further threatens aquatic species already challenged by the changing climate conditions.
There are several efforts underway to engineer plants for better nutrient acquisition using CRISPR. Most of these projects rely on the fact that there are some crops that do not require added nitrogen. These leguminous plants — like peas, beans, alfalfa and clover — get their nitrogen by teaming up with nitrogen-fixing bacteria. The bacteria take nitrogen from sources not accessible to plants and convert it into forms that plants can digest. There are a lot of research groups working to engineer plants that do not currently form these bacterial associations to cozy up to their bacterial neighbors.
An alternative approach is to engineer soil microbes so that they are less selective of their plant hosts. Pivot Bio is one company built with the specific goal of engineering soil microbes to end our dependence on synthetic fertilizers, and it’s using CRISPR in its research.
3. Engineering hardy produce to prevent food waste, so croplands go further
If disappearing cropland isn’t a big enough problem, consider that we throw away nearly half of all food produced on those shrinking lands. Food waste happens at several stages: on the farm, when diseases spoil crops; in distribution, when produce is damaged during transportation or storage; and at home or in restaurant kitchens.
Scientists are using CRISPR to engineer foods that last longer on shelves and defend themselves from pathogens so that more food makes it from farm to plate.
4. Engineering plants to prevent methane emissions and fix more carbon
Food production can be its own major source of greenhouse gases. A large portion of the world depends on rice as a staple food source and rice paddies produce a substantial amount of methane. Additionally, ruminant animals like cows generate methane when they digest roughage.
Scientists are using CRISPR to engineer rice that produces less methane and cattle feed that is easier to digest. They’re also working to make crops fix more carbon directly.
5. Revolutionizing fundamental plant research with CRISPR
Although there are many problems that CRISPR can’t yet solve directly, it can still help scientists doing basic research discover more potential solutions. For example, scientists use CRISPR to create large libraries of plants with different mutations all at once. That way, they can screen the plants for useful traits that we aren’t aware of yet. CRISPR can also help scientists move useful traits within the genome closer together, so that when breeders cross plants, the best traits are more likely to show up all in the same progeny.
This is just a sampling of the many ways plant scientists are using CRISPR to address challenges related to climate change. Innovations in industrial manufacturing helped put us in this climate quandary. Now innovations in biology, like CRISPR, can help us weather it by putting plants on the front line.