This text is part of the special Research section: climate issues
The initiative aims to decarbonize soils while offering alternative products that are non-toxic to the environment.
“Vaccinating” plants and finding sustainable solutions to avoid synthetic pesticides is what researchers, mainly from the University of Sherbrooke, are working on. Their project focuses on the use of MOFs (for metal organic framework, metal-organic networks in French). This element is made up of two pieces: on the one hand a porous metal part of nanometric size, on the other hand an organic part contained in the part.
“It’s really not big, the eye can’t see that,” says Pierre Harvey, professor of chemistry at the University of Sherbrooke and principal researcher on this project started last spring. The team also consists of Peter Moffett, professor in the Department of Biology at the same establishment, Mamadou Fall, researcher on behalf of Agriculture and Agri-Food Canada, and representatives from the Ministry of Agriculture, Fisheries and Agriculture. ‘Alimentation (MAPAQ) and the Association of Strawberry and Raspberry Producers of Quebec.
The initiative was financed by the Fonds de recherche du Québec en nature et technologies and by the Québec Program for Sustainable Agriculture, for an amount of around $250,000 per year over three years.
“The number one issue is reducing pesticide use,” says Harvey. The work therefore aims, on the one hand, to reduce the quantity of products required, and to ensure that they are not harmful to the environment and human consumption, on the other hand.
Protecting plants without harming the environment
The use of MOF is used to treat vegetable plants, both from the outside (spraying) and from the inside (injection). One of the principles therefore consists of spraying an aqueous solution based on this MOF on the plant in order to protect it against fungi, bacteria and viruses.
“There is a wide range of organic materials to make MOFs,” says Mr. Harvey. But the originality of his research project lies in the fact that it mainly focuses on certain derivatives of porphyrin, a molecular skeleton found in blood hemoglobin and in chlorophyll, for example. The metal part of the MOF is produced with non-toxic materials.
“When we want to offer something that could have a direct link with food, we make sure to do things very rigorously. We work with researchers in hospitals. They will look at the cytotoxicity of the elements that we could suggest putting in the soil and on the plants,” specifies the professor. He adds that certain porphyrin-based MOFs have already been tested in the medical community.
Once sprayed, the porphyrin molecule absorbs sunlight and comes into contact with oxygen. At that point, it becomes toxic. After verification, however, it turns out that this toxicity remains a few millimeters from the plant and is therefore not harmful to humans. On the other hand, it will kill the cells of the fungus, bacteria or virus which have attacked the plant.
“Vaccinate” the plants
The other principle consists of “vaccinating” the plants. The idea is to inject RNA (a nucleic acid present in practically all living beings, including plants) into a MOF which will be placed in the soil with the seed or when the root is still very young, the goal being that as it grows, the plant absorbs it. The MOF then helps protect the RNA while it is absorbed. Once it enters the plant, the RNA diffuses to activate the latter’s immune system, on the same model as vaccines during the pandemic. “It goes into the plant. Its immune system reacts and prepares antibodies to fight this foreign body. It equips itself against microbes that could possibly arrive,” describes the researcher.
Thus, MOFs contain the RNA and keep it intact. “It’s a bit like a capsule that protects a medicine before going into the stomach,” explains Mr. Harvey. The MOF is then absorbed by the roots of the plant. “The vaccination process is slow. So the MOF can remain in the plant without harming it,” adds the professor.
Reduce pesticide use
In agriculture, one of the main challenges in Quebec remains the reduction in the use of synthetic pesticides, believes Mr. Harvey. A reality that causes pollution and contributes to the carbonization of soils, he says. Moreover, MAPAQ hopes to reduce the amount of synthetic pesticides sold by 500,000 kg by 2030.
As for the research project, it aims to reduce the concentration of certain agents to as little as 50 or 10 parts per million (PPM). “We are really on the right track. By understanding the mechanism, we can better target the materials and products we will use in the future,” he concludes.
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