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Solving Biology's Mysteries With Plants

4 minutes

Paclitaxel is a compound that can treat cancer, salicylic acid reduces headaches and fevers, carotenoids can turn your skin orange, and miraculin changes your sense of taste. What do these awesome compounds have in common? They all come from plants!

(Describer) The woman raises her arms in a garden of daffodils, bushes, and long waving leaves.

(Describer) Tree roots dig into the ground, and branches covered in bark stretch upward.

More than 100,000 natural compounds occur in plants, and we've barely explored them.

(Describer) Lying on grass...

These small molecules are called metabolites. Just like how all the DNA in an organism forms the genome, all of the metabolites form the metabolome. Even though each metabolite can be made from only six elements, there are so many possibilities, it would take scientists thousands of years to make each one

(Describer) By tree roots...

and determine its usefulness. Luckily, plants have already done this for us. Plants have the disadvantage of being rooted to the ground. Over time, they've trialed-and-errored, making lots of compounds to see which ones help them survive and thrive best. Because they've interacted with others species, like us, for hundreds of thousands of years, some of their chemicals turn out to be really useful to us.

(Describer) In a large greenhouse...

To use plants to their full potential, we must know what chemicals they make and how they make them. What if we could study all of these chemicals at once? We could start by mapping the huge network that connects metabolites. In any living organism, molecules are being converted and shuttled, decomposed, and filled back up again and reused. It's just like a subway system! Except in biology, the people are the chemicals,

(Describer) On a platform...

and the train is the enzyme that converts and moves them. Looking at a city from above, how could you map the whole subway system?

(Describer) A few lines are shown.

Similarly, looking at a plant, how can we figure out the entire metabolome network?

(Describer) Many lines are shown.

To determine a path in a system, we need to break it. If we mutate a pathway and see how the metabolite quantities change, we could determine the connections between them.

(Describer) At a subway map...

Say the train from Central to MIT breaks. We would see students building up at Central. Not only that, anyone else traveling along the Red Line would also be affected. So, it's the redistribution of people which reveals the Red Line subway path and tells us where the train broke.

(Describer) In the greenhouse...

We can use this system's thinking to uncover the plant metabolite network. One compound, sinapoyl malate, protects the plant from UV damage by interacting with UV light, making the plant glow green. Without it, the plant would glow red. Seeing a red plant is like seeing no people at the sinapoyl malate station without knowing where the train broke or what other stations are along the route. To do that, we can mutate seeds, plant them, and choose the red ones.

(Describer) Finding them under blue light, she takes samples and puts them in vials, sealing them.

Now, we can analyze these samples by using the mass spectrometer.

(Describer) A big machine. She puts the samples in a chamber.

It measures how much of each metabolite is present in the sample. Then a program will show which compounds are affected and map that part of the network. It's like revealing the Red Line.

(Describer) ..on the subway map. In the greenhouse...

After learning how the entire metabolome works, we'll use it to engineer plants to create medicines and clean energy. We might even discover that plants have the secret to living forever. We just need to unlock their chemical mysteries.

(Describer) Title: Made with love at MIT. Accessibility provided by the US Department of Education.

Accessibility provided by the U.S. Department of Education.

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Some of the most powerful and useful things in the world come from plants. Who knew they could help unlock some of biology's mysteries by using the approach of mapping biological pathways? Part of "Science Out Loud" series.

Media Details

Runtime: 4 minutes

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