The carbon cycle is like Earth breathing in and out. The planet breathes in (absorbs) around 746 gigatons (a gigaton is two trillion pounds) of carbon dioxide each year through photosynthesis and other mechanisms. It breathes out 727 gigatons each year when plants decompose. Humans contribute 37 gigatons a year, creating an overall excess of 18 gigatons of heat-trapping CO2 – that’s why the world is warming so rapidly.
Plants already do a great job capturing carbon. The Harnessing Plants Initiative (HPI) will help them hold on to it. Even a 2% improvement in carbon storage could have a huge impact on the climate.
To make that happen, Salk scientists are developing plants with deeper, more massive roots and higher concentrations of carbon-absorbing suberin: Salk Ideal Plants.
Researchers are now conducting rigorous studies in model plants, such as Arabidopsis thaliana and Lotus japonicus, to understand the genetic signals that govern suberin content and root mass and depth. Once Salk scientists have fully illuminated the genetics that drive these traits, they can be augmented and ultimately transferred to various crops and wetland plants.
The Salk team believes this approach will store more carbon, increase crop yields and improve wetland preservation, mitigating climate change and providing more food, fuel and fiber for a growing population.
HPI is conducting two interlinked projects to improve carbon storage: CO2 Removal on a Planetary Scale (CRoPS) and Coastal Plant Restoration (CPR).
CRoPS is developing agricultural plants that store more carbon in the ground and keep it there – a simple, cost-effective and scalable way to help mitigate climate change. With larger roots and higher suberin content, Salk Ideal Plants will store large amounts of carbon and resist decomposition, keeping carbon in the ground for decades.
In addition, Salk Ideal Plants will be better suited for harsh environments and can restore carbon to depleted soil, making land more productive.
Because CRoPS targets agricultural plants, such as soybeans, corn, wheat and rice, it can tap into the existing agricultural supply chain, converting more than 75% of the world’s cropland into carbon storage.
Wetlands store between three and four gigatons of carbon each year, but they are disappearing fast. CPR researchers are identifying the genetic drivers that help wetland plants preserve land, purify water and sequester carbon. By identifying these gene combinations, and conducting accelerated molecular breeding programs, Salk scientists will create ideal wetland plants that thrive even in harsh environments.
The payoff could be enormous. Reinvigorated wetlands will store more carbon, as well as preventing CO2 from being released due to environmental degradation. Restored wetlands could sequester as much as five gigatons per year, or about 25% of the excess CO2 humans generate.
In addition to holding more carbon, restored wetlands can also help preserve threatened coral reefs and fisheries, reversing the world’s recent history of environmental degradation.
HPI is largely driven by sophisticated genomics and epigenomics (which studies the molecular tags that control whether genes get turned on or off). Once researchers fully understand how these mechanisms can produce more massive roots and higher suberin concentrations, they will transfer these traits to a new generation of crop and wetland plants.
In 2019, Wolfgang Busch’s lab identified a gene that helps control whether roots are deep or shallow. These findings will inform ongoing research and eventually Salk Ideal Plants.
Salk researchers interrogate specific genes, and study the traits (phenotypes) they produce at the Salk Institute’s climate simulation facility and a sophisticated greenhouse. There, researchers use x-rays, machine learning and many other tools to measure root growth and suberin content. This process will be replicated many times over.
Global change will only happen if Salk Ideal Plants are cultivated on hundreds of millions of acres worldwide. Even as Salk investigators solve the scientific issues, the HPI team is reaching out to industry, policymakers and others to prepare for this coming solution.