New NUE stuff

posted in: News, Science | 12

Matt Ridley, author of an upcoming book on science called The Rational Optimist, wrote an article for The Economist called The new NUE thing. NUE stands for Nitrogen Use Efficiency, a trait that can maintain yields with lower applications of costly fertilizer. Nitrogen Use Efficiency has got him, well, rationally optimistic about the environmental benefits of some GE traits.

Imagine you could wave a magic wand and boost the yield of the world’s crops, cut their cost, use fewer-fossil fuels to grow them and reduce the pollution that results from farming. Imagine, too, that you could both eliminate some hunger and return some land to rain forest. This is the scale of the prize that many in the biotechnology industry now suddenly believe is within their grasp in 2010 and the years that follow. They are in effect hoping to boost the miles-per-gallon of agriculture, except that the fuel in question is nitrogen.

In a play on those who call GE crops an “unmitigated environmental disaster,” he instead calls them an unmitigated environmental miracle. While I wouldn’t go so far as to call them a miracle, it is quite astonishing what has been achieved in the literature in so short a time, and what traits we are likely to see commercialized in the next decade.

The Union of Concerned Scientists, however, just released another report, this time questioning the usefulness of genetic engineering to make crops more nitrogen-efficient. Previously, they claimed that GE crops have failed to significantly increase yields, a couple months after an announcement of a GE trait developed by Mendel Biotechnology that does that remarkably well in soybeans. This time, while people have been talking about nitrogen use efficiency, the report gives the impression that such traits are a long way off. (I’m beginning to notice a pattern here.)

The report is titled No Sure Fix.

Besides the fact that this is not a peer-reviewed report (which does matter), I have already noticed one glaring problem – while the report focuses on pleiotropy (effect on other genes and traits) for genetically engineered traits, it ignores the same topic with regard to non-GE nitrogen-use-efficient genes. Here is the only place where the comparison is made on this topic (page 30):

Since little visible effort has been made thus
far to explore this variation, either within crop
species or their sexually compatible wild relatives,
the potential exists for improving NUE by making
use of this variation through breeding. As with
GE, however, it is possible that NUE traits within
the crop gene pool could have unintended negative
side effects. But we do not believe this risk is
as high for genes that are part of the normal crop
genome as it is for exotic genes introduced to the
crop genome through GE, or engineered genes
expressed in ways outside the typical range of
crop metabolism.
(emphasis added)

The bold sentence is a completely unreferenced, unsupported statement in the paper. Notice how they make this statement about non-GE genes for NUE traits, after just saying that little visible effort has been made exploring this variation. This is an error in scholarship and logic.

If you want to change a trait through introducing a new gene from a wild relative, you are technically introducing an exotic gene, just like with GE. Or if you are instead introducing a new allele with different expression from another variety, you are changing the expression of the genes in the crop. The Bottom Line: If you are trying to change the [nitrogen] metabolism of a crop you want to change the genes and gene expression in your crop. If you are not changing expression outside the ‘typical range of crop metabolism,’ you are not making an improvement.

Still, there are some other good things to look for in the report, such as info about enhancing nitrogen use efficiency with precision farming and other practices. I’m interested to see what people think about it?

Follow Karl Haro von Mogel:
Karl earned his Ph.D. in Plant Breeding and Plant Genetics at UW-Madison, with a minor in Life Science Communication. His dissertation was on both the genetics of sweet corn and plant genetics outreach. He recently moved back to his home state of California. His favorite produce might just be squash.