Genetic engineer here (though I've mostly worked in humans). Cross-kingdom gene transfer has been occurring due to pathogen vectors amongst plants for as long

Genetic engineer here (though I've mostly worked in humans). Cross-kingdom gene transfer has been occurring due to pathogen vectors amongst plants for as long as plants have been around. On a geological time scale the amount of gene-flow is significant, and any tricks that would allow domination and apocalypse would already have come to the fore. Most every change we make to crops weaken them as wild competitors. If you're looking for Talebian disaster, it has already happened. Seriously: Most of earth's arable land is dominated by a tiny handful of species in the order Poales, with much of the rest dominated by other invasive species brought in for grazing a few animal species. The point of genetic engineering is to help maximize yield and resilience of our intensively worked land so that we have some chance of saving what little is left of the natural world, whatever mistakes we commit now would not be materially worse than what we've already done, and we need every trick in the book to try to preserve what is left.