Got a plant with a boo-boo? Try a plant Band-Aid.
A pure form of cellulose produced by bacteria can act as a plant bandage, researchers report, significantly boosting healing and regeneration in plants. The finding, described February 12 in Science Advances, has potential implications for agriculture and plant research.
Unlike animals, plants cannot escape danger and instead rely on remarkable regenerative abilities. Bacterial cellulose — already used in human medicine for treating wounds and burns due to its biocompatibility, biodegradability and high water retention — has now been found to enhance plant healing as well.
Plant biologist Núria Sánchez Coll and colleagues were testing bacterial cellulose patches embedded with silver nanoparticles to prevent infections in wounded plants. They soon noticed wounds treated with the patches healed better and faster. “This made us interested in finding the molecular cause of this process,” says Sánchez Coll, of the Centre for Research in Agricultural Genomics in Barcelona.
To test the effectiveness of the patches as healing devices, the scientists made small cuts in the leaves of two common lab plants, Nicotiana benthamiana and Arabidopsis thaliana, applying the “Band-Aids” to half the wounds. After one week, more than 80 percent of the treated wounds had healed completely, compared with less than 20 percent of the untreated ones. Microscopic analysis showed that tissues in the treated wounds appeared healthy, while untreated wounds showed signs of distress and dehydration.
The team also discovered that the patches significantly enhance plant regeneration, particularly in cloning experiments. Many plants reproduce asexually through vegetative propagation, a process used in research and agriculture to grow a genetically identical new plant from a piece of another. When bacterial cellulose patches were added to cuttings in petri dishes, the plants regenerated faster, developing roots and leaves more quickly than untreated cuttings. Intriguingly, patches made from plant-produced cellulose did not have the same effect.
A chemical analysis revealed that the bacterial cellulose contained plant hormones, probably produced by the bacteria responsible for its synthesis. Bacteria have coevolved with plants for millions of years, producing hormones that influence plant behavior for the bacteria’s benefit. The researchers were surprised that these hormones remained intact despite previous sterilization of the patches to avoid contamination. “We think that the cellulose matrix is so dense that it preserves the hormones, which remain bioactive,” Sánchez Coll says.
At a genetic level, the bacterial cellulose–induced healing appears distinct from normal plant wound repair. The bacterial cellulose triggered a different set of genes, turning off some typically involved with healing while activating others related to infection defense. The researchers believe this altered response results from a combination of factors: the wound itself, the presence of bacterial hormones and the plant’s reaction to the bacterial cellulose as a foreign body, potentially triggering a defensive mechanism.
Although bacterial cellulose has been widely used in human medicine, this is the first time it has been found to have intrinsic biological activity, says Anna Roig, a materials scientist at the Institute of Materials Science of Barcelona who wasn’t involved in the study.
Plant scientist Javier Agustí, also not involved in the study, sees enormous biotechnological potential. “I would be very interested in seeing how well it works in real crops,” says Agustí, of the Institute for Plant Molecular and Cellular Biology of Plants in Valencia, Spain,
While still in early stages, the findings do suggest potential applications in agriculture, Sánchez Coll says, such as facilitating grafting, preserving cut plant material or serving as a growth medium in laboratories. Other research groups are already looking at these findings at the molecular level, trying to determine if they apply to other regeneration processes that aren’t yet fully understood.