New non-polluting biopesticides to combat plant diseases

A revolutionary strategy to combat pests that affect agricultural crops, from insects to fungi, is to use epigenetics to stimulate the immune memory of plants with natural products and thus improve their resistance to diseases without altering the genome.

Continuing in its line of seeking new molecular strategies and new bioproducts that improve the defense mechanisms of plants in a sustainable manner, a team of researchers from the I+D+i Center for Biodiversity and Sustainable Development (CBDS) of the Polytechnic University of Madrid (UPM), in collaboration with the Institute of Agricultural Sciences (ICA) of the Higher Council for Scientific Research (CSIC), all these entities in Spain, has shown that the use of natural extracts based on essential oils produces changes in the immune memory of plants, which acquire new properties that increase their tolerance against high-impact diseases. These induced epigenetic effects endure over time, keeping the cell genome intact but alert.

The use of natural and non-polluting products in the agricultural and forestry environment has been a priority within the strategies of the European Community since 2018. Likewise, the search for new active and non-polluting biopesticides to combat high-impact plant diseases constitutes an essential research area. In this context, epigenetic alteration in plants using natural products can become a sustainable and harmless tool for plants to acquire new properties that make them more tolerant to diseases. This is the line of work that researchers at the UPM and the CSIC have followed, the use of epigenetics as an eco-sustainable tool in the field of plant pathology.

Plant attacked by insects. (Photo: Elizabeth A. Sellers, USGS)

Epigenetics is a natural mechanism that allows modifications without altering the genome. Plants, due to their exposure to changing and often unfavorable growing conditions, are adept at epigenetic regulation as it helps them survive. In the laboratory led by Marta Berrocal-Lobo, a researcher at CBDS and UPM, the epigenetic effects of various natural products on plant cells are studied and characterized, without altering their genome, but acquiring improved immunity. Some of these natural products are essential oils from different species of aromatic plants. Researchers from the Institute of Agricultural Sciences of the CSIC, led by Azucena González Coloma, have characterized the biopesticide potential of essential oils from different species of aromatic plants, in particular, Artemisia absinthium, an ancestral aromatic plant, already used in Egypt by its healing properties, and also used in the food industry.

The analyzes carried out at the UPM indicate that the essential oil of Artemisia absinthium is capable of producing epigenetic changes in tomato plants, increasing their tolerance to the disease caused by Fusarium oxysporum sp., a highly virulent fungus that causes great losses in numerous species both horticultural and forestry. The results have shown that the essential oil of Artemisia absinthium is capable of producing changes in the DNA, without altering its sequence, but changing the expression levels of proteins that produce epigenetic changes and modify the methylation patterns of the tomato, acquiring an immune memory. improved against Fusarium sp. with respect to the plants not treated with the oil.

In the opinion of Marta Berrocal-Lobo, the researcher who has led the work: “These results will allow us to delve into our knowledge of the epigenetic effects of these and other natural products to improve the immune memory of plants. Directed epigenetics, through the use of natural products, could constitute a new tool for the application of countless natural products in different plant species and with very diverse interest, both industrial and environmental. In addition, it would serve to reduce the use of soil and water pollutants, contributing to food security and eco-sustainable agroforestry practice.”

The study is titled “Essential Oils Prime Epigenetic and Metabolomic Changes in Tomato Defense Against Fusarium oxysporum.” And it has been published in the academic journal Frontiers in Plant Science. (Source: UPM)