2. In The Shoes Of A Plant | Liang Song
November 8, 2017 6 a.m.
Liang Song is working hard to save her best friends: plants. She's trying to make them stronger. Like, strong enough to withstand a statewide drought.
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Margot: San Diego is one of the largest scientific research hubs in the country. So, who are the intrepid scientists in search of discovery, pushing the frontiers of human knowledge. This is Rad Scientist, where the scientist becomes the subject. I'm your host, Margot Wohl. Today's Rad Scientist is a plant fanatic who seeks to make plants more resistant to changes in the environment.
Liang: Okay, so my name is Liang Song, and I'm a Research Associate in the Salk Institute.
When I was a kid and I play with plants because they simply don't run away from me, and they're beautiful, and I also sometimes love to harvest some of the nectars from plants. Usually it's supposed to be for the bees, but since I was able to harvest some flowers so I also just directly enjoy it, so that's how it got me started.
Margot: One thing about Liang that’s a little unusual? She talks about plants like they’re people.
Liang: If we put ourselves into the shoe of a plant, and then you will say, "Oh, all these plant species are so amazing. They are so self-sufficient and so generous."
Margot: Liang spends a lot of time thinking about plants, specifically their DNA. Inside every cell of every living creature is a very detailed instruction manual that tells it how to function. That instruction manual – the genome – is made up of DNA. And for a long time, scientists had only read a couple pages. But by the early 2000s, they were starting to decode entire manuals for some species.
Liang: Before, we study basically gene by gene and now we can profile the entire genome, and even to compare different genomes. So the capacity to gain information is unparalleled.
Margot: In fact, she studies the first plant to ever have its genome decoded: Arabidopsis.
Liang: Arabidopsis is a cousin of cabbage and kale. Vegetables, maybe kids hate to eat them, but we all know they are good for the health.
Margot: It’s related to some familiar vegetables, but Liang says you probably wouldn’t want it on your dinner plate.
Liang: Oh, I don't think it's yummy enough.
Margot : Liang isn’t the only scientist using Arabidopsis to study plant genetics. Last year alone,
over 3000 studies used it! Why? Well, it has a short life cycle, a relatively small genome, which means sequencing can happen quicker, and it’s easy to grow in the lab. Liang uses Arabidopsis as a model to understand how plants deal with stressful environmental conditions – like the extreme weather conditions that may result from climate change. One big one? Drought.
Liang: In the past five years, and drought is a big issue in California, and the plants need to respond and to deal with that…. We look at our plants and they look very peaceful, and they don't speak, and usually they don't move.
Margot: If these plants could talk, they’d probably be screaming, "I'm so thirsty! It's so dry out here!” But instead, they use a special chemical language.
Liang: Arabidopsis makes a hormone called absiasic acid.
Margot: So...plants have hormones.
Liang: Plants have hormones.
Margot: And this one is basically like the Paul Revere of hormones. It travels through the veins of the plant, sending a message to the rest of the plant tissue. "The British- I mean- the drought is coming. Hey leaf, hey stem, hey roots! It's really dry in here!"
Liang: This will in turn affect the gene expression.
Margot: The plant starts turning on and off genes to start or stop the production of new proteins. Maybe the plant wants to stop making that new leaf to save energy. Or maybe it wants to grow new roots to capture more water. And that’s what Liang is really interested in. Can we use genetics to improve the way plants deal with drought? To try to answer this question, Liang tests tens of thousands of plants. And all those plants live in a small windowless warehouse lit up by fluorescent bulbs.
Liang: We just got a visitor here, she wants to see our plants. We grow about 20,000 plants for an experiment?
Margot: Thousands of small green leafed plants with tiny white flowers. Basically she wants to use them to figure out which genes are being turned on and off when the warning hormone rides by - signaling tough times ahead. Then, she has to figure out what these genes are doing
Liang: We play with the expression level of these genes, we can usually have them express more or express less, and to see whether there's a change of phenotype at the plant level.
Margot: Phenotype is some outward change that you can see on the plants like seed number or leaf size. In her first large experiment, she found a group of six similar looking genes that when turned on, made the plant worse at dealing with stress. Wait, that's not what Liang wants.
Liang: The logic is, like if we increase the expression of these genes and they are more vulnerable to the stresses, and again maybe if we go the opposite side, if we decrease the expression of the genes, then there will be more resistance to the stress.
Margot: Liang has a pretty good idea of which genes might be important for drought resistance. And because a lot of these genes are also found in many fruits and vegetables, her research could have a big impact on farming.
Liang: There are many ways to improve plants by characterizing all these plant responses at the molecular level, we understand which genes are the most important ones, and we can do the targeted breeding focusing on these genes to stack all the good features together.
Margot: And that's where our conversation inevitably ends up on the hotly debated subject of GMOs, or Genetically Modified Organisms.
Liang: We can sell fear more easily than selling hope, right? I have always have two things bear in mind, and one is the crop or the plant production, and the other is the environment, and that the argument I make to myself is the more efficient we make our plants and our crops are, and the more land we can preserve for the wild species.
Margot: One thing is pretty clear, Liang is passionate about her science and how it can benefit the earth and mankind. But she's also cares about her research subjects, the plants.
Liang: I talk to my plants.
Margot: Which brings us to this episode's Moment of Xenopus: Dialogues With a Plant.
How do you feel like growing here?
Liang: What do you feel if I ask you to donate a leaf to me?
Liang: What's your favorite day?
Plant: My favorite day?
Liang: Uh-huh (affirmative).
Margot: Turns out, plants only respond with dad jokes.
Liang: I just think you guys are the ultimate introverts. You keep all the secrets to yourselves, and only the most curious human beings can probably uncover a small part of your secret.
Margot: Rad scientist was produced and edited by me, Margot. With original scores and editing help by Grant Fisher. Logo is by Kyle Fisher , no relation. This podcast is supported by the KPBS Explore Project, bringing local content to the radio. This episode was produced by me, Margot Wohl. Grant Fisher is our audio mix master and theme song composer. Shahla Farzan is script editor. Logo by Kyle Fisher. At KPBS, Emily Jankowski is technical director, Melanie Drogseth is program coordinator, Jill Linder is programming manager, Nate John is innovation specialist, and John Decker is director of programming. Additional music was by Blue Dot Sessions, Foolboymedia, Dave Girtsman and Symphoid. Also, a shoutout to Jackie Sojico and Daniel Potter for feedback for this episode.
And of course, a shout out to the plants that contributed to this episode.
Liang: Thank you for contributing to science, and also to human food, to all the entire human society.
Margot: Hey, do you know a rad scientist? If so, email me at firstname.lastname@example.org. And
you can also check me out on twitter @radscientistpod. Until next episode, stay rad.