What is so compelling about a 25-year old article? I found myself on the Nature Biotechnology website earlier this week. Wednesday, to be exact. And I was surprised to see, on the “most emailed” list, an article published in 1987. Over the course of the week, it disappeared from the list. Moved down Thursday, and gone by the weekend. So you’ll just have to trust me.
The article is about optimizing the transfer genes into tomato plants. Published in 1987, puts it square in the infancy of GMOs. The first field trials on herbicide-resistant tobacco plants happened just one year earlier. In this article, researchers used bacteria, Agrobacterium tumefaciens, to insert a gene that makes the plants resistant to Round-up. The ability of Agrobacterium to transfer genes into plants was first described in 1977. Basically, the bacteria have a small loop of DNA, the T1 plasmid, which can be shuttled into plant cells. In nature, the bacteria use this to turn plants into their personal resource warehouses. Agrobacterium give plants genes to make a class of chemicals called opines. They grow in tumors on the plants, and the bacteria exploit the plant’s new opines for their own energy and nitrogen production.
We can denude the T1 plasmid of all its genes except for the ones responsible for DNA transfer, and then insert the genes we are interested in. In this case, herbicide tolerance. Voila, genetically modified organism.
The point of this paper was really to optimize gene transfer into tomatoes using Agrobacterium. It’s a finicky bacteria, so you have to optimize your procedure for each species. We’re still doing this.
Despite my best googling efforts, I’m not sure WHY this article popped up on the most emailed list. Do share if you have an idea. Its humility and openness was refreshing: they didn’t have all the answers. The discussion is full of speculation and unknowns: they didn’t know exactly why some things worked better than others. Papers, behemoths now, come across differently.
But my favorite part? The “Methods” section was about as long as the “Results” section. I wouldn’t feel uncomfortable attempting to repeat their experiments with those methods in hand, and the last time I saw a cotyledon was middle school. Now we shuttle Methods to the online supplemental information. Even with all that space, people aren’t wont to wax eloquently on laboratory techniques. Often we just say “as was previously described…(ref X),” which may, or may not, actually be the case.
Improving scientific accuracy and reproducibility has been a hot topic lately. If that’s the goal, more people should read this article and think about the way it used to be.
Original paper: Fillatti et al. Efficient transfer of a glyphosate tolerance gene into tomato using a binary Agrobacterium tumefaciens vector. Biotechnology, July 1987.