It might be possible. If it happens, it will most likely happen by accident.
I caught a blog a few months ago…can’t find it now, and I have absolutely no idea how accurate it is. But the basic idea was that a research group for a major chemical producer was genetically tailoring a bacterium.
This was a modification of a bacterium that is commonly found in soils around the world, and what it does, as I understand it, is break down soils and release nitrogen which is then taken up by plant roots. It apparently exists in a commensal relationship with plants.
The modified bacterium was to produce alcohol as part of its workings on material it was breaking down. This was seen as a win-win situation. The bacteria could be bred and used to assist in large scale composting, and the alcohol that was produced could be collected and used for fuel. So at once, we get fertilizer and fuel. Great idea, right?
Well, goes the blog message, testing of this bacterium using some sort of sterile soil tests (I didn’t get this…made little sense to me…) led to conclusions by the gov’t that this bacterium was safe and did not pose an environmental hazard.
However, some intrepid soul ran tests with this bacterium in soil that included live plants, and in every test all the plants died. Seems that the bacterium would happily displace the unmodified variety on and around plant roots, and the alcohol it produced then poisoned the plants.
The blogger then indulged in some heavy breathing and went on about how, had this bacterium been released for the intended purpose, it would inevitably have killed all plant life on Earth.
So, is this true? Accurately stated? Representing events that really occurred? I have no idea. I recall thinking at the time that the site appeared credible and the information provided was at least plausible. However, I’m a physicist, not a geneticist or any kind of plant biologist. I know in general terms what the state of the art is in genetic engineering, but I certainly don’t know in detail. I’m also somewhat skeptical about the claim that any single bacterium could kill everything, but I can’t say for sure that this is not credible.
So, if it happens, it’ll happen something like that. In our incredible wisdom, we’ll build something that we don’t think is dangerous, and it’ll get away from us, and it’ll kill us.
Is it possible? Probably.