Plant Transformation

Sometimes among all of the tedious protocols and mundane inconclusive data, I forget that I'm doing something amazing and incredibly powerful. Almost all my experiments require altering a living organism to do my bidding--to hold onto and replicate a piece of DNA that I'm interested in or to produce an enzyme that I want a lot of. Thanks to iGEM this summer I've gotten to learn some new soon-to-be-tedious protocols that seem absolutely thrilling now, and the experience is reminding me of how awesome (in the real sense of the word) genetic engineering is.

The team is working with the model organism for plants, Arabidopsis thaliana, and we've finally gotten our DNA ready to insert. There are two methods for introducing new DNA into plant cells: One is to literally shoot it in with a gene gun, and the other is to hijack infectious bacteria that naturally inject their own DNA into the plant genome. These agrobacteria can themselves be engineered to insert only the DNA we want and not the genes that make the plant sick. Many biological technologies are just that--biological, modifications of processes that occur in nature as DNA is chopped, copied, and swapped between organisms. I love when these technologies require the use of whole, living organisms instead of just purified genes or enzymes, as in agrobcterium transformation of plants, or the assembly in yeast of the Venter Institute's synthetic genome.

In the wild, agrobacterium can infect plants through the roots or get in through damaged tissues, but in the lab we have to gently convince the bacteria to get into the plant's seeds so that the engineered trait will last into future generations. In arabidopsis this happens by dipping the flowers into a thick slurry of the bacteria mixed with a soapy solution that very easily gets sucked up into the plant cells. It's remarkably simple really--just scrape the thick lawn of cells growing on agar plates into the liquid, then dip the whole pot right in and swirl it around.

We have to wait a while to see if any of it worked, an eternity for people like me used to fast-growing E. coli, but even if we don't get what we expected, I still think plants and plant engineering are pretty cool!