Genetically Engineered Crops - a Threat to Soil Fertility?

A non-technical condensate of the scientific article

Summary

A hypothesis has been proposed that special DNA present in all genetically engineered plants might enable unrelated microorganism species in the soil to mate. This would lead to a progressing loss of species diversity in the soil. Soil fertility is greatly dependent on this diversity. It this hypothesis is right, graudally increasing damage to soil fertility might occur, in the worst case irreversibly and to an important extent.

GE crops contain artificial genetic elements (vectors) that are designed to promote the uptake of an inserted gene into the DNA of an unrelated species (for an explanation, see How are genes engineered" [ML] (fairly simple). ). Some reports indicate that genes can be transferred from the roots of plants to soil microorganisms. Another source is plant debris. It has also been experimentally demonstrated that naked DNA (without the shielding or cell or nuclear membranes) can survive for long times in the soil, long enough to be available for uptake by soil bacteria.

An interdisciplinary group of scientific experts has advanced the hypothesis that these vectors from GE crops might promote transfer of DNA between unrelated soil microorganism species. Thereby changes and disturbances could occur that even might result in new species. But also minor changes in the genetic setup might make a microorganism unable to function normally. This might affect its ability to contribute adequately to the microecological interplay in the soil.

The soil microecology represents a very complex interdependence of a very large number of species (there may be over 1000 in one gram of soil biomass). Gene transfer would, if the proposed mechanism works in reality to a significant extent, cause imbalances and disruptions in the microecology. In the long run this mechanism would result in a progressive decrease of soil diverstiy, which if extensive, might damage soil fertility which is greatly dependent on this diversity and on the ecological balance between different species.

This hypothesis and its background is explained for the layman in non-technical terms in "Genetically Engineered Crops and Soil Fertility"

PSRAST calls for experimental studies to test this hypothesis. We conclude:

As:

  1. The suggested mechanism might in the worst case cause irreparable, widespread, cumulative and persistent damage to soil fertility
  2. The genes causing the complication might in the worst case spread uncontrollably over vast areas
  3. The available evidence supporting this possibility is not insignificant
  4. None of presently grown GE crops are of any significant value to mankind,

we find that it is unjustifiable to continue the culture of any transgenic crops until it has been established experimentally beyond reasonable doubt that the proposed mechanism may not result in disturbances of soil ecology.

The title of this article is "Genetically Engineered Crops - A Threat to Soil Fertility?". The contributors include experts on soil ecology, soil biology, microbial ecology, horizontal gene transfer, genetics and agriculture.

This article was drafted already in spring 1999. But it was not published because we could not disclose the names of the authors for reasons explained at a separate webpage.

Now we feel we cannot take the responsibility to wait any more, so the article is published without disclosing the names.

To the article "Genetically Engineered Crops - A Threat to Soil Fertility?"  [AL]

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