Submitted by Jane Durkin on Mon, 28/04/2025 - 12:46
Targeting a newly discovered vulnerability in the signals that cyst nematodes use to infect plant roots could be a powerful method for reducing the damage the parasitic worms cause in crops such as soya beans.
A new study from the University of Cambridge in collaboration with the John Innes Centre, Iowa State University and the United States Department of Agriculture, opens the door to promising new routes to nematode control for crop protection and food security.
The implications also hold potential for reducing disease caused by parasitic nematodes in other organisms, including animals.
Cyst nematodes are root parasites with a major impact on global agriculture. Infection can cause huge losses in crop yields – up to 90% in cereals and 80% in potatoes.
Researchers have identified a single protein in cyst nematodes that triggers dozens of molecules called effectors, that the microscopic roundworms release inside roots to hijack plant cells and make themselves at home.
Though the protein – a transcription factor that binds to genes, turning them on or off – is likely one of several that regulate effector production, researchers found that without it the nematode infection is severely reduced – by 80%.
The research was published in Proceedings of the National Academy of Sciences (PNAS) on 10 March 2025.
A conversation between parasite and host
Effectors are the key molecular mechanism for nematode invasions in plant roots.
Nematode worms are sophisticated pathogens that after hatching in soil, burrow their way into a root. Once inside, they look for a single cell to take over. When they find what they’re looking for, they start not by feeding but by communicating.
The nematodes use molecules called effectors to deliver a message to a plant cell. This message prompts the cell to change, turning into a cell type not usually found in a plant root. Then all the neighboring cells change, and they fuse together to form a new organ designed to feed the worm.
For years, scientists who study nematodes have been investigating effectors in the hope that targeting them could reduce infections by cyst nematodes.
Until now those efforts have been like a game of 'whack-a-mole’. Taking one effector away has very little impact. Nematodes produce hundreds of different effectors and can rapidly adapt if just one is blocked.
Finding SUGR-1
Since individual efforts to target individual effectors have little effect, researchers have had to dig deeper.
Using data from collaborators at Iowa State University, researchers from the Plant-Parasite / Pathogen Interactions group at the University of Cambridge identified a transcription factor in the nematode’s glands that becomes active when effectors are produced.
Their analysis showed 58 effector genes are triggered by this transcription factor, which they call the Subventral-Gland Regulator (SUGR-1).
They found that SUGR-1 is activated by signals – ‘effectostimulins’ – from the roots, explaining why SUGR-1 activates when exposed to root extracts from plants that are known nematode hosts.
"The most exciting thing for me about this paper is the picture it paints of a self-reinforcing cycle driving nematode infection of plants,” says Professor Sebastian Eves-van den Akker, head of the Plant-Parasite / Pathogen Interactions group at Cambridge and lead author of the paper.
“They break plant cells, sense some signals released and respond in a way which increases their ability to break host cells."
SUGR-1 acts like an orchestra conductor
Professor Eves-van den Akker likens this mechanism of plant-parasitism by nematodes to an orchestra.
“In this study we found the conductor of the orchestra (SUGR1).” he explains.
“The nematode uses many genes to infect the plant. Like an orchestra it is the combined action of everyone that gives rise to the music.”
“From previous work we knew that the genes nematodes use to infect the plant are controlled in a coordinated manner – that some ‘unifier’ must be controlling them.”
“This gave rise to the conductor of the orchestra idea about eight years ago and has been a central tenet of the Cambridge lab.”
How it could work in fields
Currently, crop rotation and cultivars bred to have some nematode resistance are the main control measures for managing cyst nematodes. The improved understanding of how nematodes trick plants into becoming willing hosts should eventually expand that toolbox.
“A promising new strategy for nematode control could be to remove the trigger of effector production” says Anika Damm, PhD candidate at the University of Cambridge and co-first-author of this study.
Breeding companies could develop crop varieties with reduced effectostimulin content – either by conventional or precision breeding. Another option could be the development of crop varieties that produce RNA that, once consumed by the nematode, prevents production of SUGR-1.
“With nematodes, you don’t necessarily have to kill off every worm. If you reduce infection by 40%, that’s a big deal. It would make a real dent in crop damages,” says Professor Thomas Baum, Distinguished Professor at Iowa State University and co-author of the study.
‘Just the beginning’
Professors Eves-van den Akker and Baum plan to continue working together on cyst nematode research. “It has been a fruitful partnership for years.” Professor Baum says.
“If you were to draw up the way you want to interact with a scientific collaborator, it would be just like this. You build on each other and freely share to make advances that help both camps.”
The researchers expect future studies will uncover more about the genetic and molecular mechanics of effector production, which should offer additional ways to disrupt the crucial signaling between cyst nematodes and their plant hosts.
“SUGR-1 is just the first one that jumped off the page. But we know there are others. This is only the beginning. There will be many targets,” Professor Baum says.
Reference: Pellegrin and Damm et al., The SUbventral-Gland Regulator (SUGR-1) of nematode virulence, Proceedings of the National Academy of Sciences (PNAS), 122, https://doi.org/10.1073/pnas.2415861122 (2025)
Image: Photo of a cyst nematode's head viewed through a high-power microscope shows its esophageal glands, which produce effectors it uses to infect host plants. The image was digitally edited to highlight the glands. The subventral glands responsible for SUGR-1 are colored blue. Photo illustration by Tom Maier and Thomas Baum/Iowa State University.