Modifying the viruses payload wouldn't make it a universal infector. Modifying viruses for gene therapy is even more anti-competitive than modifying bacteria. In modifying a virus, you don't just add traits to the existing genetic payload, you swap out great chunks of the viruses existing machinery. A highly infectious virus carrying a trait you want does no good if it wipes out every cell it infects. So, what you end up with is more of a nano-scale lab tool than a viable disease.
But, let's suppose I am totally wrong and your fears are entirely justified. I'm not taking this tack to bait you or anything, it's just a good thing to consider. A pan-species infecting form of THC-adder virus gets out and starts infecting random plant cells with the genes that could conceivably be used to synthesize THC. What happens then? In most cases (and by most, I mean an arbitrary row of nines with a dot between the second and third) nothing noticeable will occur. No THC synthesis, no real change in the plant. Directing a virus to insert its genes into a specific chunk of a cell's chromosome is still beyond us. You have to get lucky to have the gene end up somewhere it can get expressed in an organism.
So, with a spreading plague of reeferness, we're going to see a bunch of "lucky" events, some of which will occur in the seed-forming bodies of plants, producing offspring that will synthesize THC somewhere in their tissues. Then a force much scarier than the DEA steps in and probably wipes every last one of them out. Every erg of energy a plant gets is normally devoted to growing. metabolizing, or reproducing. If you've stuck in some plans that say to spend it synthesizing a molecule that's otherwise useless to the plant, it's not spending as much energy doing the stuff it needs to do. When it's not performing as well as its neighbors and predators are, it's going to fall behind and probably go extinct. Since no-one would realize that this particular plant was of the rare THC-making strain, noone's probably going to care when it shuffles off.
There are two common exceptions to the old innovation-equals-death problem. One is isolated areas. If the virus manages to catch a plant somewhere with low competition for resources, the gene-expressing plants might well survive and even last long enough to mutate up a use for all that THC. The other area? Human-controlled areas. We love to take crazy, messed-up plants and cultivate them at the expense of everything else. If humans find your non-pot THCmaker, they might choose to cultivate it for whatever reason. Heck, we already cultivate deeply malformed crab apples and bananas - and the founding fathers wouldn't even recognize what we call maize these days. One more cultivated plant in human history wouldn't come as much of a shock to anyone.
Re: BioHacking
But, let's suppose I am totally wrong and your fears are entirely justified. I'm not taking this tack to bait you or anything, it's just a good thing to consider. A pan-species infecting form of THC-adder virus gets out and starts infecting random plant cells with the genes that could conceivably be used to synthesize THC. What happens then? In most cases (and by most, I mean an arbitrary row of nines with a dot between the second and third) nothing noticeable will occur. No THC synthesis, no real change in the plant. Directing a virus to insert its genes into a specific chunk of a cell's chromosome is still beyond us. You have to get lucky to have the gene end up somewhere it can get expressed in an organism.
So, with a spreading plague of reeferness, we're going to see a bunch of "lucky" events, some of which will occur in the seed-forming bodies of plants, producing offspring that will synthesize THC somewhere in their tissues. Then a force much scarier than the DEA steps in and probably wipes every last one of them out. Every erg of energy a plant gets is normally devoted to growing. metabolizing, or reproducing. If you've stuck in some plans that say to spend it synthesizing a molecule that's otherwise useless to the plant, it's not spending as much energy doing the stuff it needs to do. When it's not performing as well as its neighbors and predators are, it's going to fall behind and probably go extinct. Since no-one would realize that this particular plant was of the rare THC-making strain, noone's probably going to care when it shuffles off.
There are two common exceptions to the old innovation-equals-death problem. One is isolated areas. If the virus manages to catch a plant somewhere with low competition for resources, the gene-expressing plants might well survive and even last long enough to mutate up a use for all that THC. The other area? Human-controlled areas. We love to take crazy, messed-up plants and cultivate them at the expense of everything else. If humans find your non-pot THCmaker, they might choose to cultivate it for whatever reason. Heck, we already cultivate deeply malformed crab apples and bananas - and the founding fathers wouldn't even recognize what we call maize these days. One more cultivated plant in human history wouldn't come as much of a shock to anyone.