In a recent study, Mexican scientists demonstrated that genetically engineered (GE) cotton continues to spread into wild native species. The researchers identified transgenic plant traits, such as insecticidal properties and resistance to glyphosate. The transgene introgression has already been ongoing for several generations. This current study builds on earlier research, indicating that transgenic cotton is much more widespread in native populations than previously known. Mexico is the center of origin of cotton.
The research was carried out on the Yucatán Peninsula in Mexico. The researchers wanted to find out whether transgenes had been introduced into wild populations of cotton (Gossypium hirsutum). Genetically engineered cotton has been cultivated in Mexico for over 25 years, though not in the areas studied. The analysis examined whether the plants contained glyphosate resistance genes (epsps) or transgenes producing insecticidal Bt toxins (such as Cry1Ac or Cry2Ab). In addition, the researchers sought to determine whether any ecological effects were occurring, for example, in the composition of ant species associated with the plants.
Almost half of the wild cotton plants examined contained transgenes; at one site, the figure was as high as around 70 per cent. In most cases, the plants showed glyphosate resistance, but insecticidal activity was also frequently observed, and in numerous samples, different transgenes were detected simultaneously in a single plant.
The composition of ant populations differed significantly between wild plants expressing transgenes and transgene-negative wild plants. These ants benefit from plant secretions, ward off pests and play a role in seed dispersal. An earlier study had already revealed other changes in ant populations associated with the transgenic wild cotton plants. The findings available to date also include effects on the gut flora of insects that feed on the plants.
The altered interactions between the plants and their environment may have long-term consequences for cotton species and their ecosystems. As the uncontrolled spread of transgenic constructs affects the centre of origin of cotton, there is a risk that important genetic resources, e.g. for breeding new cotton varieties, will be irretrievably lost.
Contact:
Christoph Then, info@testbiotech.org, Tel +49 151 54638040
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