A project to develop genetically modified, pest-resistant peas has been abandoned after tests showed the peas cause lung damage in mice.
Protein Kills Pea Weevils
Field peas are susceptible to pea weevils, which lay their eggs on pea pods. The gene for a protein capable of killing pea weevil pests was transferred from the common bean to the peas. This protein does not normally cause allergic reactions in mice or people.
But when the protein is expressed in the pea, its structure becomes subtly different from the original. Researchers say that this indicates a potential for unpredicted and unintended effects due to such structural changes. In this case, it was probably caused by differences in the ways that the two plants produce proteins.
Trials showed that the GM peas were almost completely resistant to pea weevils. But mice injected with the protein showed a hypersensitive skin response, and those exposed to it in airborne form developed airway inflammation and lung damage. The effect was the same whether the protein was taken from raw peas or cooked peas.
In the early 1990s, a similar situation happened when researchers engineered a new strain of soy bean by adding a gene taken from brazil nuts. But that project ended when it was discovered that the hybrid was likely to trigger a major attack in people with brazil nut allergies.