Arabidopsis as a model plant - Dr Sean Cutler

Sean -  Because of its size, it's a very small weed and it grows relatively quickly, and also has a small genome.  And because of those features, geneticists early on selected it as being a good model for lab studies, in the way that the fruit fly is a good model for a lot of other insects.

Kat -  And how long have scientists been studying Arabidopsis?

Sean -  The first studies go back longer than the '50s, but I would say, modern Arabidopsis research, where a lot of people started working on it in parallel with similar building tools and working together that really started I would say in the '80s.

Kat -  And we know about model systems for studying animal biology, fruit flies, zebra fish, mice.  Why do we need a plant model?

Sean -  Well, plants feed the planet.  We need to understand how plants use water, how they use nitrogen, how the different inputs that we give them are converted into the materials that we harvest for food or fibre, and now of course, for fuels as well.  What we would like to be able to do is make those processes of modern agriculture more efficient and get by with less of the inputs that we use, so that we can feed our growing population with the available land and resources that we have.

Kat -  So obviously, a big challenge with climate change in a lot of places in the world where we grow crops getting a lot drier.

Sean -  Yeah, drought is a really big problem all over the world, but also, flooding is a really big problem.  So the levels of floods and flood-prone areas are going up.  Climate is becoming more erratic, it appears, with drought-prone areas getting longer droughts, more severe droughts and flood-prone areas getting more longer and more severe floods.  And it turns out that plant biologists are getting a handle on how to make plants grow better under conditions of flood, how to make plants grow better when there's water limitation or other nutrient limitations.

Kat -  So tell me a bit about the kind of approach you're taking, this chemical genetics approach.  What do we mean by that?

Sean -  So, classical genetics used to and still does, try to figure out how a pathway works by breaking it with a mutation.  As if you're trying to understand how a car worked and you were from Mars, you would cut the line between the brakes and the brake pedals and the car wouldn't stop, and you would conclude that the brake pedal has something to do with slowing down cars and genetics has that same logic where you break genes and you look at what the consequences are for the organism, and try to infer their functions that way.  

One of the things that we're realising in many organisms, but it's particularly true in plants is that, there are often backup systems.  So, plants as a rule always have two brake pedals and if you're trying to do that experiment where you cut the line on the brakes, you might never discover the existence of a braking system.  Chemicals often, for technical reasons that I don't need to get in to, chemicals can sometimes indiscriminately cut all of the brakes, instead of just cutting one particular brake cord in this, now overwrought, analogy.  So chemicals provide an additional tool in the arsenal that a geneticist can use to help understand a pathway and they can be particularly helpful where redundancy may have been preventing a geneticist from fully understanding how a system works.