2 March 2023

Dutch researchers bet on bacteria to reduce pesticide use


Researchers at the University of Wageningen in the Netherlands will study the potential of bacteria to fight plant pests without damaging the soil ecosystem. Crucial is the action of peptides, biodegradable proteins produced by the microorganisms

by Matteo Cavallito


Bacteria could provide an alternative to chemical pesticides. That’s the hypothesis of a group of researchers at Wageningen University & Research (WUR), an institution based in the Netherlands. The team of scientists, led by Marnix Medema, a professor at the Wageningen University, will spend the next few years studying the potential of these microorganisms to fight plant pests without damaging the soil ecosystem.

This initiative is funded by the Netherlands Organization for Scientific Research (NWO), with 5.5 million euros. The project has a five-year duration.

Peptides produced by bacteria also protect plants

“Chemical pesticides are a major problem that needs to be solved fast,” Medema explains in a statement released by Wageningen University. “These products are bad for biodiversity, but could also have negative effects on plant microbiomes (beneficial bacteria) and on human health. We want to help solve this problem.” How? The answer, the researchers explain, may lie in the bacteria. Or, rather, in their ability to produce a particular category of substances: that of antimicrobial peptides.

“Peptides are basically small proteins, and some of them can kill pathogens without detriment to the human body or biodiversity,” the authors say. The hope, they add, is to discover easily biodegradable peptides that can target bacteria and fungi and not affect the remaining microbiome of a plant.

The importance of “selective” contrast

These aspects are crucial. Indeed, to protect crops, it is necessary to target those pathogens that threaten plant survival. The counteracting action exerted by many pesticides, however, risks not only promoting the pollution of the soil and its fruits. But also of damaging those decisive microorganisms that contribute to the balance of the ecosystem.

For example, scientists have long emphasized the increasingly obvious link between soil fertility and microbial biodiversity. Microorganisms, in fact, act as a genuine resource bank that the plant can draw on selectively according to its needs. They contribute to the decomposition of organic matter and the release of essential mineral nutrients.

Groundbreaking research

“We currently know very little about which bacteria produce these peptides in a plant”, says Medema. ‘But new technology has now become available that will allow us to identify peptides on a large scale and test their biological activities.” The study aims not only to identify the bacteria but also to develop a product that can be applied to crops by involving researchers in a broad-spectrum analysis. Researchers from Leiden and Zurich Universities, for example, will engage in metabolite analysis and evaluate the action of the peptides and their ability to attack pathogens without harming beneficial microorganisms.

Researchers from the University Medical Center Groningen, meanwhile, will study the effects of bacterial products on the human gut microbiome. Finally, WUR’s Department of Social Sciences will analyze the possible social acceptance of the new technology by trying to understand whether people will be willing to consume vegetables treated with antimicrobial peptides. Identifying the peptide-producing bacteria, however, the researchers admit, will still take years.

Pesticides increasingly impactful

The study of bacteria as an alternative to pesticides assumes important significance in the current European framework. The EU regulation aims to reduce the risks associated with plant protection products by 50 percent by 2030. In Brussels’ crosshairs, in particular, are 54 particularly hazardous substances that are classified as “candidates for substitution” because of their potential impact on health, soil and the environment. Under the current Regulation, member states are required to replace these compounds with safer alternatives.

Last year, a report by Pesticide Action Network (PAN), a federation that brings together hundreds of NGOs in 60 different countries, showed that contamination of fruits and vegetables in the Continent has grown significantly over the past decade, with a 53 percent increase in recorded cases between 2011 and 2019.