For billions of years, plants and their ancestors, the cyanobacteria, have been powerful agents of change on Earth. They pumped out oxygen and squirreled away carbon dioxide, transforming the chemistry of the biosphere. They colonized land and allowed animal life to follow, changing the course of evolution.
Now molecular biologist Wolfgang Busch wants to recast plants into agents of stability, offsetting the tremendous amount of climate-warming carbon dioxide that humans are pouring into the environment. As part of the Harnessing Plants Initiative at the Salk Institute in La Jolla, California, Busch is working on a bold scheme to modify major crop plants so that they grow deeper, bigger root systems, leaving those carbon-rich roots embedded in the soil after harvest time. While we humans get to work cutting back on our carbon emissions, the plants will be busily lending a hand.
A fundamental challenge with this idea is that the shallow roots of crops normally rot and release much of their carbon over the course of the year. The Harnessing Plants team, under the direction of Joanne Chory, has come up with a clever solution. The researchers are modifying plants so that they produce suberin (the primary ingredient in cork) in their roots. Suberin stubbornly resists decomposition, so the roots masses of these "Salk Ideal Plants" could remain in the soil for an extremely long time without sending their carbon back into the air.
Many different parts of the plan have to come together just right for the Harnessing Plants Initiative to work. The plants have to bury carbon efficiently and effectively. The modified crops have to provide all the same seed yield as before. Farmers need to embrace these crops on a global scale. And the rest of the world still needs to keep working on cutting carbon emissions, since plants alone won't save our bacon.
On the other hand, the humongous scale of agriculture provides a unique opportunity for large-scale decarbonization. Busch and his colleagues are therefore plowing full-speed ahead (with some COVID speed bumps along the way) to see whether carbon-sequestering corn and wheat can help us turn down the heat from climate change while also recharging the planet's carbon-depleted soils. An edited version of my conversation with Busch follows.
