With the world’s population surpassing 8 billion, the urgency of ensuring an ample food supply has never been more pronounced. The Netherlands, renowned as the globe’s second-largest food exporter, excels in cultivating a diverse array of crops. Yet, the specter of plant diseases like downy mildew looms large, posing a grave threat to farmers’ yields.
Dutch researchers from Delft University of Technology have made a groundbreaking discovery: the first-ever method to monitor infections in plants in real-time, without the need to destroy them. This revolutionary breakthrough will pave the way for breeding new, resistant crops that yield higher outputs while reducing pesticide use. The findings mark a significant leap forward in agricultural innovation.
Farmers growing lettuce face a formidable challenge in combating diseases like downy mildew, which causes yellow or brown spots on the upper surfaces of leaves. Delft scientists delved into this issue, focusing on downy mildew infections in lettuce, a plant species where such infections are typically only visible in their later stages. Their discovery opens the door to a new era of resilient and high-yielding crop varieties, heralding a brighter and more sustainable future for agriculture.
“There are indeed lettuce varieties that are resistant to downy mildew, but similar to the coronavirus; the disease continually evolves into new variants that can still infect resistant plants. This forces scientists and breeders into a constant race to develop new resistant crops in response to evolving diseases,” explains physicist Jos de Wit, who collaborated with biologists from Utrecht University for his doctoral research.
To cultivate crops like lettuce that can better withstand diseases, researchers from Delft University of Technology and Utrecht University have developed a groundbreaking method to image common plant infections without harming the plant and at a much faster rate than traditional microscopy. This innovation is set to revolutionize our understanding of how plant infections progress and pave the way for cultivating disease-resistant crops.
“Until now, researchers had to kill a plant for each step in the process, stain it, and then examine it under a microscope,” says Jeroen Kalkman, associate professor in imaging physics. “Now, with this new imaging technique, we can track how a disease develops in a living plant in real-time.”
With this cutting-edge instrument, scientists can gain invaluable insights that will help develop crops with enhanced resilience to a wide range of diseases.
“These crops require fewer pesticides, are better equipped to withstand extreme weather conditions, and ultimately yield much more. This means that, in the long run, more people on Earth can be fed,” Kalkman notes.
“The technique we used is called dynamic optical coherence tomography (dOCT),” says De Wit. “It involves emitting light and measuring the time it takes for that light to reflect back, similar to ultrasound but with light instead of sound. In just one and a half seconds, we can capture around 50 to 100 images of an infected lettuce leaf. We can effectively map plant diseases with dOCT because the pathogens move more than the plant cells. By assigning colors to areas with more movement, we can generate a strong contrast between the pathogen and the plant. Without dOCT, the disease would only be visible at a much later stage.”
The researchers have not only successfully tested their instrument on lettuce but also on other crops like radishes and peppers, which are affected by parasitic roundworms. However, additional research is necessary to refine this technique into a user-friendly tool for biologists without technical expertise. Kalkman expressed his enthusiasm to further this research and bridge the gap between technology and biology.
Journal reference:
- Jos de Wit, Sebastian Tonn, Mon-Ray Shao, Guido Van den Ackerveken, Jeroen Kalkman. Revealing real-time 3D in vivo pathogen dynamics in plants by label-free optical coherence tomography. Nature Communications, 2024; DOI: 10.1038/s41467-024-52594-x