Gene Transfer in bees – Does gene transfer from rapeseed pollen to microorganisms take place in the digestive tract of bees?
(2001 - 2004) Federal Agricultural Research Centre (FAL), Institute of Agroecology; BraunschweigTopic
Bees feed on pollen and nectar. Bees collect pollen from transgenic plants just as they would from conventional plants.
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Honeybees and two species of wild bee, which are known to collect rapeseed pollen (the earth bumblebee and the mason bee), were studied to see if microorganisms in their digestive tract could incorporate DNA from GM rapeseed pollen into their genomes. The research was carried out in association with field trials for herbicide tolerant rapeseed (Liberty Link) that took place from 2001 to 2003. |
The GM rapeseed carries a gene for herbicide tolerance (pat‑gene ), which protects it from herbicides with the active ingredient glufosinate -ammonium.
Some types of soil bacteria naturally produce glufosinate as a defence agent against other bacteria. Many types of bacteria are naturally resistant to glufosinate.
Summary
The transfer of glufosinate resistance genes from rapeseed pollen to microorganisms in the gastrointestinal tract of bees could not be detected under field conditions and is therefore considered highly unlikely.
Intestinal bacteria are known to be capable of incorporating foreign DNA fragments from the environment into their genome. This potential should be taken into consideration when evaluating the safety of transgenic plants. The horizontal transfer of a pat glufosinate resistance gene to microorganisms should not be an ecological concern, because many bacteria are naturally resistant to glufosinate.
Cultivating glufosinate resistant rapeseed is considered harmless with respect to horizontal gene transfer to bacteria.
Experiment description
At the beginning of the experiment, researchers assessed the diversity of gastrointestinal bacteria that are naturally found in honeybees, bumblebees and mason bees. This was done by using a genetic fingerprinting technique optimised for characterising bacteria.
Bacteria were cultured on various substrates to determine the prevalence of bacteria naturally resistant to glufosinate. Glufosinate resistant bacteria underwent PCR (polymerase chain reaction) to see if they assimilated the pat gene.
Researchers used molecular techniques to see if a common type of gastrointestinal bacteria (Bacillus) has the genetic potential to generate mechanisms for incorporating foreign DNA.
Results
Some 140 different species of bacteria were identified in the digestive tract of the bees. Some of them, like Simonsiella, Lactobacillus or Leminorella were widespread in all three bee species.More than a third of all gastrointestinal bacteria were tolerant of glufosinate. The resistant bacteria came from a wide range of groups.
None of the resistant bacteria had absorbed the pat-gene from GM rapeseed pollen. The resistance was natural and had nothing to do with growing GM rapeseed.
Bacteria from the group Bacillus were present in the bees’ digest tract, a group that contains many species that are thought to have the potential to assimilate free DNA from the environment.
The project was completed on 30 April 2004.
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