Laying the Groundwork

When I tell people that got a NC Space Grant Fellowship for plant biology research, the first question I get asked is “So when do your plants go to space?” When I reply, “They don’t. My plants will be in the lab,” I get quizzical looks. What most people don’t realize is that most space biology research is done here on the ground.

Spaceflight botany experiments—like the rockets they are launched on—only get one shot. In spaceflight, fuel is precious, cargo space is precious, and astronaut time is very precious, so experiments are designed to be as quick and fail-proof as possible with the minimum amount of supplies. If a mistake is made, if equipment fails, or if a scientist has an idea for a follow-up experiment that might give a bit more information, too bad; little room exists for correcting mid-course. For every botany experiment that goes into space, dozens of experiments are performed on the ground to check and double-check that all the parts of it work.

My advisor, Imara Perera, and my labmate, Eric Land, meticulously preparing seeds for a spaceflight mission. Photo by NASA.
Positioning the tiny Arabidopsis seeds is a job for steady hands. Photo by NASA.

After every flight experiment, unanswered questions abound. Scientists ask things like: How universal are our results? What caused some of changes we observed? Do our experimental results predict something useful? These type of questions are normal for any biology experiment. You will never find a biologist who proclaims “Ah, ha! I have finally figured everything out about my study system.” Answering follow-up questions makes the most sense to tinker with first on the ground. Terrestrial experiments give space biologists the luxury to try out different approaches and repeat things quickly.

My research aims to answer these type of unanswered questions, to create special “glowing plants” for future experiments, and probably to unearth a bunch of new questions along the way.

The ECMS model used for my lab’s plant biology experiments. Small casettes of seedlings were grown on these rotor modules. Some were spun quickly to simulate Earth gravity. Some were left to grow in microgravity. Photo by NASA.
These seeds are ready to germinate in the ECMS growth chamber on the ISS. Photo by NASA.

Several years ago, other folks in my lab did two experiments on the International Space Station looking at the biochemical changes that occur in plants during exposure to microgravity. These scientists wanted to know how “weightless” plants figured out which way to grow. Even thought these experiments weren’t performed at the same time, they did use the same equipment, which means we could compare results from them fairly easily. My colleagues found that plants in both experiments activated some of the same genes that control the production of certain plant signaling-chemicals in microgravity, but not in normal gravity. (I will talk more about these genes and signaling chemicals in a future blog post.)

Frozen seedlings from my lab’s experiments returned to Earth for RNA analysis. Photo from Imara Perera.

For my experiments on earth I want to answer a few questions:

  1. What is the best equipment to replicate these experiments on earth?
  2. What is the timeline for the changes in these genes in simulated-microgravity?
  3. What happens to biochemical signals in plants with mutations that stop them from making some of these signaling-chemicals?
  4. Do these changes with mutant plants differ when these plants are exposed to simulated-microgravity?

I also want to create biotech tools that will help me and future scientists better understand the timing of these biochemical signals. I will genetically engineer plants with cells that glow very faintly, like a distant firefly, when the plants “turn on” genes that control these signaling chemicals. With these glowing plants, astronauts could easily gather information about when the plants are making signaling-chemicals during spaceflight by simply letting automated cameras record the glow. No need to haul up chemistry equipment or bring samples back down to earth.

An Arabidopsis plant engineered to contain firefly genes. The plant cells glow when certain genes are active. Photo by Steve A. Kay, National Science Foundation.

So how I am going to simulate the effects of microgravity without leaving Earth? I am going to trick my plants with a slowly rotating device called a clinostat. How am I going to make glowing plants? I’m going to reprogram some bacteria and use them to put firefly genes in plants.

More on that to come in future blog posts…

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