Bacteria as an alternative to chemical pesticides

Published on
February 2, 2023

Everything that plants absorb eventually ends up on your plate and so in your body, including pesticides. Pesticides are bad for your health and the environment, which is why the EU wants to drastically reduce their use.

Professor Marnix Medema of Wageningen University & Research (WUR) is coordinator of a research consortium that will be spending the next few years looking for an alternative to chemical pesticides in the agriculture sector. They believe that antimicrobial peptides may offer a solution.

The Netherlands Organisation for Scientific Research (NWO) has granted three consortia, including this one, a total of €5.5 million over the next five years as part of an NWO Kennis- en Innovatieconvenant-programme to investigate the role of the microbiome in the nutrient cycle called Microbiome: Healthy from soil to gut and back.

No detriment to people and the environment

‘Chemical pesticides are a major problem that needs to be solved fast,’ says Medema. ‘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.’

A solution may come from the bacteria that occur naturally on plants and produce antimicrobial peptides. Peptides are basically small proteins, and some of them can kill pathogens without detriment to the human body or biodiversity.

Medema and his colleagues hope to discover readily biodegradable peptides that will target bacteria and fungi and leave the rest of the microbiome of a plant alone. Moreover, if the bacteria that make these peptides can be deployed as biological crop protection agents, this will ensure that they only produce them when and where they are needed.

‘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.’

Cycle: from plant to social acceptance

A unique feature of this consortium is that they will be studying the entire innovation and supply chain: from product development to consumption. Researchers of the universities of Leiden and Zürich will look into the metabolomics (the analysis of metabolites, which are the products of metabolism) and investigate if the peptides only work against the pathogens, and not the beneficial bacteria, for example.

UMC Groningen is involved in the field of human health research, to study the effects on the gut microbiome. WUR’s Social Sciences department will focus on the social acceptance of the new technology. They want to know if consumers will be willing to consume vegetables treated with antimicrobial peptides, and what will be required to persuade the various parties and stakeholders to cooperate in this development.

‘This is the first time a study is being conducted into whether the bacteria in plants that produce such peptides actually end up colonizing the gut,’ says Medema. ‘Peptides are already used in food, and these are perfectly safe.’

Process of many years

Ultimately, the aim is to create a usable product, but this will be a process of many years. That is why the researchers are cooperating with a number of companies who will help with some of the technical aspects of the research.

‘At the end of the project, we want to test the peptide-producing bacteria we have found in a greenhouse setting to see if the concept really works,’ concludes Medema. ‘We eventually hope to identify peptide-producing bacteria that can serve as a starting point for the development of a product. But whether or not this is actually possible will only be revealed some years down the road.’