Exactamundo.
You again.
My goodness, where to start?
The significance of inserting a single gene from one organism into another is... nothing. Lateral gene transfers occur frequently in nature. In fact, every time you get a viral infection, those viruses insert their entire genome into your cells. Usually, they force your cells to become virus factories. But not always. Sometimes, they integrate into your chromosomes and become a permanent part of your genome. Sometimes, they integrate into the chromosomes in germ cells, where they can become a permanent part of the human genome. Our genome, in fact, contains anywhere from 5-8% of viral DNA. One protein that is essential for the formation of the placenta is coded by a virus that became part of the mammalian genome millions of years ago.
Of course, every time you consume food, you consume significant quantities of DNA from other organisms--including organisms of completely different kingdoms. (Quick biology lesson: the five kingdoms are bacteria, archaea, fungus, plant, and animal.) Have you had adverse effects from that? I doubt it, unless the DNA was inside of a pathogen.
I'm not surprised you don't know this, actually. You didn't even know that CO2 is the basic building block of *all* biological molecules (no exceptions).
If someone were trying to engineer botulinum toxin into lettuce or something like that, I'd be worried. But engineering plants to be resistant to rust or insects or whatever--it's no big deal. We've been engineering other organisms for millennia. Our tools have gotten much better, that's all.
Have you ever considered maybe taking some basic science classes before you try to match wits against an experienced scientist again?