Scientist unveils man-made genome, key to creating life from scratch

Field burning of plant residues to prevent disease is a serious cause of air pollution throughout the US. If we had an organism that could decompose the plant material and produce alcohol from it; then we'd have a win-win situation. A sellable product and get rid of plant residues without burning. We could add it to gasoline. We could cook with it. We could drink grass wine-although whether that would taste very good is anyone's guess. Regardless, there are many uses for alcohol.

So, genes were taken out of another bacterium, and put into Klebsiella-planticola in the right place to result in alcohol production. Once that was done, the plan was to rake the plant residue from the fields, gather it into containers, and allow it to be decomposed by Klebsiella-planticola. But, Klebsiella would produce alcohol, which it normally does not do. The alcohol production would be performed in a bucket in the barn. But what would you do with the sludge left at the bottom of the bucket once the plant material was decomposed? Think about a wine barrel or beer barrel after the wine or beer has been produced? There is a good thick layer of sludge left at the bottom. After Klebsiella-planticola has decomposed plant material, the sludge left at the bottom would be high in nitrogen and phosphorus and sulfur and magnesium and calcium-all of those materials that make a perfectly wonderful fertilizer. This material could be spread as a fertilizer then, and there wouldn't be a waste product in this system at all. A win-win-win situation.

But my colleagues and I asked the question: What is the effect of the sludge when put on fields? Would it contain live Klebsiella-planticola engineered to produce alcohol? Yes, it would. Once the sludge was spread it onto fields in the form of fertilizer, would the Klebsiella-planticola get into root systems? Would it have an effect on ecological balance; on the biological integrity of the ecosystem; or on the agricultural soil that the fertilizer would be spread on?

One of the experiments that Michael Holmes did for his Ph.D. work was to bring typical agricultural soil into the lab, sieve it so it was nice and uniform, and place it in small containers. We tested it to make sure it had not lost any of the typical soil organisms, and indeed, we found a very typical soil food web present in the soil. We divided up the soil into pint-size Mason jars, added a sterile wheat seedling in every jar, and made certain that each jar was the same as all the jars.

Into a third of the jars we just added water. Into another third of the jars, the not-engineered Klebsiella-planticola, the parent organism, was added. Into a final third of the jars, the genetically engineered microorganism was added.

The wheat plants grew quite well in the Mason jars in the laboratory incubator, until about a week after we started the experiment. We came into the laboratory one morning, opened up the incubator and went, "Oh my God, some of the plants are dead. What's gone wrong? What did we do wrong?" We started removing the Mason jars from the incubator. When we were done splitting up the Mason jars, we found that every one of the genetically engineered plants in the Mason jars was dead. Wheat with the parent bacterium, the normal bacterium, was alive and growing well. Wheat plants in the water-only treatment were alive and growing well.

From that experiment, we might suspect that there's a problem with this genetically engineered microorganism. The logical extrapolation from this experiment is to suggest that it is possible to make a genetically engineered microorganism that would kill all terrestrial plants. Since Klebsiella-planticola is in the root system of all terrestrial plants, presumably all terrestrial plants would be at risk.

So what does Klebsiella-planticola do in root systems? The parent bacterium makes a slime layer that helps it stick to the plant's roots. The engineered bacterium makes about 17 parts per million alcohol. What is the level of alcohol that is toxic to roots? About one part per million. The engineered bacterium makes the plants drunk, and kills them.

But I am not trying to say that all genetically engineered organisms are technological terrors. What I am saying is that we have to test each and every genetically engineered organism and make sure that it really does not have unexpected, unpredicted effects.