Andart

Bacterial Reverse Bioengineering

Science: A New Tack on Herbicide Resistance, Discovery and Directed Evolution of a Glyphosate Tolerance Gene by Castle et al. (Science, Vol 304, Issue 5674, 1151-1154, subscription required).

A new and elegant way of creating herbicide resistant crops. Monsanto has made plenty of money on crops that resist the herbicide glyphosate, but now the patent on the herbicide has expired. So, how to reverse-engineer the resistance of the plants (which is still patented)?

Nature can find a way. Castle et al. started by looking for common bacteria that could detoxify glyphosate. After finding one (there are almost always one bacterium somewhere that does any desired chemical operation) they made its detoxification enzyme more powerful by directed evolution. Shuffle the enzyme gene, add it back to the bacteria, expose them to the herbicide, pick up the best strains and repeat. After 11 rounds of selection they had a 10,000 times more efficient enxyme. This gene was then added to corn and worked well, with no toxic byproducts from detoxification or adverse effects on the plant health and reproduction.

While this will hardly make the greens any happier (it is still a GMO, even if it means Monsanto will get lower profit margins) it is a wonderful example of how to use the power of evolution to improve a product. In fact, it demonstrates a promising way of having bacteria do reverse engineering of patented genes, which might be a way of getting out from the invention-restricting effects of gene patents without removing them as incentives for creativity. Unless this method ends up heavily patented and restricted, of course.