Abstract
The impact of genetically modified plants on plant-associated and surrounding soil microorganisms is an uninvestigated area of environmental risk assessment. Biological markers such as lysine racemase, phosphomannose isomerase, and sulfadiazine are in use or suggested for use in plant genetic transformation technologies to confirm that the uptake of DNA has occurred. Similar to the effects of antibiotic-resistance genes, these markers might change the host plant's microbiota. Taking into account the importance of the microbiota in plant growth and protection from pathogens as well as in the lives of both humans and animals, we propose novel criteria for the environmental risk assessment of genetically modified plants: the composition of the plant microbiota and plant-associated soil microbiota. In addition to the possible impact of genetic transformation technologies on the plant microbiota highlighted in this report, the microbiota of genetically modified plants (and/or plant-associated soil microbiota) should be investigated in a comparative study of genetically modified and unmodified plant-derived microbiotas. This could potentially provide important information to farmers when considering the adoption of genetically modified plants.