A new biological mixture has just appeared.
“Picotila,” bioengineered immune system proteins that are part plant and part animal, may help flora better fight disease, researchers report in Science for March 3. Protein hybrids use the unique flexible immune system of animals, giving plants the ability to fight new pathogens .
Flora usually rely on physical barriers to keep disease-causing microbes at bay. If something unusual gets inside the plants, internal sensors sound the alarm, and the infected cells die. But as pathogens develop ways to evade these defenses, plants cannot adapt in real time. An animal’s adaptive immune system can produce large amounts of antibodies within weeks of exposure to a pathogen.
In a proof-of-concept study, scientists genetically modified the internal sensor of one plant to create animal antibodies. This approach harnesses the power of the adaptive immune system to make nearly unlimited adjustments to target invaders and transmits them to plants, says plant immunologist Xinnian Dong, a researcher at the Howard Hughes Medical Institute at Duke University who was not involved in the work.
Crops in particular could benefit from having a more adaptive immune system, as many farms grow fields filled with only one type of plant, Dong says. In nature, diversity can help protect vulnerable plants from pathogens and pests that spread disease. The farm is more like a buffet.
Researchers have been able to tune plant genes for disease resistance, but finding the right genes and editing them can take more than a decade, says photopathologist Sophien Kamun of Sainsbury’s Laboratories in Norwich, England. He and his colleagues wanted to know if plant protection could get an extra boost with animal-inspired solutions.
To create picobodies, the team fused small antibodies from llamas and alpacas to a protein called Pik-1, which is found in cells Nicotiana benthamiana , a close relative of tobacco plants. Pik-1 normally detects a protein that helps the deadly fungus infect plants. For this test, animal antibodies were designed to target fluorescent proteins
The team found that plants with picobiles killed cells exposed to the fluorescent proteins, leading to dead spots on the leaves. Of the 11 versions tested, four were not toxic to leaves and only caused cell death when picobodies attached to a specific protein they created bound.
Moreover, picotillae can be combined to give plants more than one way to attack a foreign invader. This tactic may be useful to target pathogens with a nimble ability to evade some immune responses from different angles.
It is theoretically possible to create picobides “against virtually any pathogen we study,” Kamun says. But not all pikobody combinations worked together in tests. “It’s a bit hit or miss,” he says. “We need more basic knowledge to improve bioengineering.”
