Can Crops Be Vaccinated?

Ultimately overshadowed by the coronavirus crisis, 2020 was the International Year of Plant Health, as proclaimed by the United Nations. The world’s growing population has an enormous demand for food but also for textiles, medicines, and fuels made from plants. "Today, however, around 40 percent of crop yields are still lost to pests and diseases," says RWTH Professor Uwe Conrath, Head of the Department of Plant Biochemistry and Molecular Biology, where systemic acquired resistance, a component of the plant immune system, is being researched. The resistance can be provoked by a moderate initial infection – similar to vaccinations for humans.

Years ago, Conrath coined the term “defense priming”: He had discovered that a fungus-infected cucumber plant developed resistance not only to that particular fungus, but to a wide range of fungi, bacteria, viruses, and abiotic stresses. When the cells come into contact with the pathogen, they enter a state of alert, he explains. The plant synthesizes protein molecules, for example, which then lie dormant in its entire organism and are only very strongly activated when attacked again. Therefore, priming – sensitization after initial infection – is an extremely energy-efficient reaction: It is only switched on in an emergency and does not inhibit the growth and yield of plants.