Researchers from the Agricultural Research Service (ARS), the principal in-house research agency of the US Department of Agriculture, have successfully improved the guayule plant in order to enhance its rubber output.
Rubber is usually made from petroleum or from the Asian rubber tree plant, but it can also be produced from a plant called “guayule.” Guayule is a woody desert shrub cultivated in the southwestern US as a source of natural rubber (latex), organic resins, and high-energy biofuel feedstock.
ARS chemist Colleen McMahan and her colleagues molecular biologists GriselPonciano, Niu Dong, and Dante Placido and technician Trinh Huynh, in Albany, California, developed improved guayule for rubber production.
In 2013, Bridgestone Americas and ARS’s Bioproducts Research Unit entered into a research agreement to evaluate ARS’s genetically improved guayule. In 2016, they delivered more than 3,000 experimental guayule plants to research partner Bridgestone Americas in Eloy, Arizona, for field testing.
“The genetic modification increased rubber content dramatically in the lab, and we have seen that in the greenhouse as well,” says McMahan. Their work with Bridgestone has allowed them to evaluate the plants and test them in the field.
But a long-term goal is to supplement current guayule germplasm collections with plants that have important traits such as drought and disease resistance. The team needed to find guayule types that weren’t already in ARS’s collection.
“Three years ago, a separate project with Cornell University was initiated to DNA fingerprint all known guayule germplasm in public seed collections that breeders rely on to create new types,” says McMahan. “In the process, we searched for new—and old—sources to add to the collection,” because this isn’t the first time guayule has been used as a rubber source.
During World War II, Manzanar, California, was the site of a Japanese-American internment camp where guayule plants were selected, bred, cultivated, and processed into natural rubber to aid in the war effort. Manzanar is now a National Park Service Historic Site.