Rubisco. Chances are you’ve never heard of it even though, according to biologist and post-doctoral researcher at the University of Illinois Amanda Cavanagh, “It’s probably the most abundant protein in the world.” Cavanagh happens to be a huge fan of Rubisco.
So what is it? Rubisco is short for ribulose-1,5-bisphosphate carboxylase/oxygenase, a really big chemical name that is a lot harder to pronounce and even harder to remember. It also happens to be a big protein molecule found in the leaves of almost all plants.
Using energy from the sun, Rubisco make sugar molecules using the carbon from carbon dioxide is gets from air. The process may sound familiar – it’s called photosynthesis.
Unfortunately for plants, Rubisco isn’t too careful about what it picks up from the air. When it uses oxygen instead of carbon dioxide, Rubisco produces a toxic compound in a process called photorespiration. The plant is then forced to detoxify. Cavanagh calls this Rubisco’s “one fatal flaw.”
Unfortunately for us, plants use up a ton of energy during the complicated photorespiration process, rendering some plants pretty bad at making leaves (or food for animals) as a result.
In true human form, Cavanagh and her colleagues have set out to “hack” photosynthesis in an effort to fix Rubisco’s fatal flaw. While some productive plants like corn and sugar cane have created a workaround naturally, most plants haven’t. One such easy to work with plant is tobacco, the subject of the “hacking” (or experiments) taking place in the Realizing Increased Photosynthetic Efficiency (RIPE) research program at the University of Illinois.
Researchers put new genes in old plants, effectively shutting down the natural detoxification process and setting up a new, seemingly more efficient one. “They grew faster and they grew up to 40 percent bigger” both in greenhouses and outside, Cavanagh said.
Super tobacco – just what we need!
Scientists are keen on replicating the process in plants that humans rely on for food such as tomatoes, soybeans, and black-eyed peas. Funders of the project include the Bill and Melinda Gates Foundation and the U.S. Department of Agriculture. According to Cavanagh, project funders have expressed “interested in making the biggest impact” with the Rubisco hack in sub-Saharan Africa. The USDA has already applied for a patent on the plants that are engineered via the project despite the need for more research. Significant questions remain like: will the plants actually produce more fruit, or simply more stalks and leaves?
“We could feed up to 200 million additional people with the calories lost to photorespiration in the Midwestern U.S. each year,” said Donald Ort, principal investigator at the Robert Emerson Professor of Plant Science and Crop Sciences at the Carl R. Woese Institute for Genomic Biology.
Whether or not bioengineered food is your thing, it will be a while before farmers are able to plant crops with this hacked version of photosynthesis.
Photo Credit: Claire Benjamin/RIPE Project