Surprising new research has now uncovered alarming new findings about how pollutants are accumulating inside pumpkins. These colorful veggies are a popular produce star of the cucurbit family. Study DOI 10.1016/j.plaphy.2025.110280 uncovers the important function that duplicative proteins play in these tolerant plants. Yet these proteins dramatically increase the absorption of toxic chemicals. Should we be eating pumpkins and related veggies?
That study, led by the Center’s Greg Rothwell, was released early this year. It investigates the interactions of major latex-like protein with polycyclic aromatic hydrocarbons (PAH) and their binding affinity. PAHs are hazardous substances and common environmental contaminants that become highly toxic when they build up in plants grown for consumption. In a key finding, researchers found the shape of these proteins is central to determining how much pollutants accumulate in the aboveground portions of pumpkins. This discovery does not only pertain to the humble cucumber.
Unraveling the Mechanism
Studies have demonstrated that these ubiquitous major latex-like proteins are able to bind with PAHs. This poorly understood process allows them to build up in plant tissues. This binding affinity affects the degree to which pollutants bioaccumulate in pumpkins. It further distinguishes pumpkins from other plants that don’t demonstrate the same propensity to gather toxins.
Inui Hideyuki, one of the researchers who worked on the study, said those implications of these findings are deeply worrying.
“The pollutants don’t easily break down and thus pose a health risk to people who eat the fruit. Interestingly, other plants don’t do this and so I became interested in why this happens in this group specifically.” – Inui Hideyuki
Their subsequent investigation revealed that certain pumpkin species naturally contained increased levels of protein in their sap. This increase in disproportionate burdens is due to their increased accumulation of pollutants.
“However, these proteins exist in many other plants, and even among the gourds, there are varieties that are more prone to accumulating pollutants than others. We then noticed that in the highly accumulating varieties, there are higher concentrations of the protein in the sap.” – Inui Hideyuki
The Role of Protein Structure
What these discoveries show is that the shape of these proteins is incredibly important. It has a direct impact on how well they bind to pollutants. Plant researchers found that only secreted proteins are able to move systemically through plants. This surprising finding reveals a critical difference between low-polluting vs high-polluting varieties.
“Only secreted proteins can migrate inside the plant and be transported to the aboveground parts. Therefore, this seems to be the distinguishing factor between low-pollution and high-pollution plant varieties.” – Inui Hideyuki
This finding creates interesting avenues for future research. With these advances, scientists are better positioned to investigate genetic modifications that could limit the accumulation of harmful pollutants in food crops.
Future Implications
Inui imagines a revolutionized farming approach. By changing how these contaminant-transporting proteins behave, allowing them to divert harmful contaminants away from the plant’s edible parts, he is working to develop crop varieties that are safer for food production.
“By controlling the behavior of contaminant-transporting proteins, through genetic modification of their pollutant-binding ability or its excretion into the plant sap, we believe it will be possible to cultivate safe crops that do not accumulate harmful chemicals in their edible parts.” – Inui Hideyuki
Inui said she hoped to use that research to improve the capabilities of plants to absorb soil pollutants.
“I started this research because I was looking for plants that can detect and digest pollutants effectively. Therefore, I also envision that we could use the knowledge gained through this work for creating plants that are more effective in absorbing soil pollutants. This could turn into a technology for cleaning contaminated soils.” – Inui Hideyuki