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Question

Effect of GM crop root exudates on soil micro flora?

Submitted by: anandhallad


Answer

Expert response from Kevin Folta

Professor and Chairman, Horticultural Sciences Department, University of Florida

Thursday, 06/11/2014 14:58

There is only one report in a lower-impact journal regarding this topic. Dinel et al. (2003) use a sensitive method to analyze plant material and soil associated with one line of Bt and one line of non-Bt corn. The authors claim to find significant differences in various molecules — quite a few, actually. They also suggest negative effects on soil bacteria associated with the Bt corn.

 

My main concern is that the data from this limited study are done with improper controls and then are overinterpreted. The authors use one Bt line and one non-Bt line. The problem is that the two foundational lines are different. In other words, it is not the same line — one has the Bt gene, and the other does not. That would be the valid comparison. Even better, they should have tested several different lines, both Bt and non-Bt. What they show is that two different corn lines are, well, different.

 

The results are at odds with other high-resolution analyses of gene expression that show that a Bt-containing line and its corresponding non-Bt control are basically equivalent.

 

Maybe the authors are on to something, maybe not — it can’t be determined by this limited data set. However, the authors may feel a little stronger about their conclusions. They state, “The concerns raised by our data are serious enough to emphasize the need to further research the impact of Bt maize on short- and long-term soil quality.”

 

That was more than eleven years ago. These "serious" findings were never reproduced or reported ever again by other groups. What’s particularly telling is that these authors found the results “serious” and of “concern” yet never even followed up with their own more complete study.

 

This one is another one-off paper of the negative effects of transgenic plants that disappears into the "where are they now?" file.