As the world’s population exceeds 8 billion, the urgency of producing enough food intensifies. The Netherlands is the second-largest food exporter globally, effectively growing a diverse range of crops. Nevertheless, plant diseases like downy mildew present serious risks, threatening farmers’ yields. Researchers have now created a groundbreaking method to detect plant infections in real-time without harming the plants. This advancement will assist in developing new crop varieties that are resistant to diseases, leading to higher yields while minimizing the use of pesticides.
With the global populace climbing past 8 billion, ensuring food production meets demand becomes ever more critical. The Netherlands ranks as the second-largest food exporter worldwide, known for its effective cultivation of numerous crops. However, diseases in plants, specifically downy mildew, can severely impact harvests. Researchers from Delft University of Technology have introduced an innovative technique to monitor plant infections in real-time without damaging the plants. Such advancements will support the breeding of new, resilient crop varieties that produce greater yields and reduce pesticide reliance. These findings have been published in Nature Communications.
Resistant crops
Lettuce farmers favor varieties that are resistant to several diseases, including downy mildew, which leads to yellow or brown spots on leaves. Scientists from Delft University explored downy mildew infections in lettuce, a crop where signs of infection usually appear late. “While some lettuce varieties are resistant to downy mildew, the pathogen continually evolves new strains, much like the coronavirus, which keeps scientists and breeders in a perpetual struggle to develop fresh resistant varieties,” explains physicist Jos de Wit, who conducted this research alongside biologists from Utrecht University.
Real-time tracking
In their efforts to cultivate more resilient crops like lettuce, researchers at Delft University of Technology and Utrecht University have pioneered a method to visualize common plant infections. This technique allows for imaging without having to sacrifice the plant, and it is significantly quicker than traditional microscopy methods. “Previously, researchers had to destroy a plant at each stage, apply stains, and then analyze it under a microscope,” says Jeroen Kalkman, an associate professor in imaging physics. “Now, with this novel imaging technology, we can observe how a disease progresses in a live plant in real-time.”
Higher yields
Often, plant scientists are unaware of how infections evolve inside a plant and what factors contribute to the resistance observed in certain crops. This new device offers valuable insights, facilitating the development of crops with enhanced resistance to various diseases. “These robust crops require fewer pesticides, are better able to resist harsh weather, and ultimately provide significantly higher yields. This means that, in the future, we can feed more people around the globe,” Kalkman emphasizes.
Mapping plant diseases
“The method we utilized is known as dynamic optical coherence tomography (dOCT),” De Wit explains. “It works by emitting light and measuring how long it takes for that light to bounce back, akin to an ultrasound but using light instead of sound. In just a minute and a half, we can capture about 50 to 100 images of an infected lettuce leaf. We can effectively track plant diseases with dOCT because the pathogens move more than the plant cells do. By coloring areas based on their movement, we create a stark contrast between the pathogen and the plant. Without dOCT, the disease would only become apparent much later.”
A practical tool
Beyond lettuce, the researchers have confirmed that their technique works for other crops, including radishes and peppers affected by parasitic roundworms. More studies are necessary to refine this method into a user-friendly tool for biologists with non-technical backgrounds. Kalkman states: “I am enthusiastic about advancing this research to connect technology and biology efficiently.”
This research was conducted in partnership with Guido Van den Ackerveken’s team at Utrecht University and the vegetable and fruit breeder Rijk Zwaan based in De Lier, Netherlands.
