Symbiogenics to feed a drought stricken world

Higher temperatures and water stress are expected to diminish rice yields by 15% in the coming years. But scientists hope to fight back with a tiny fungus that helps increase rice harvests with less water. Host Bruce Gellerman asks University of Washington biology and forestry researcher Dr. Regina Redman about the hearty rice plant that can grow more with less water.
Transcript

GELLERMAN: Here’s a potential recipe for feeding a planet stressed by climate change: Take some rice plants, add some potato sugar, a bit of antibiotics and – here’s the secret ingredient – a tiny fungus and voila! You get a new experimental strategy for growing food crops that can survive and thrive in a world growing warmer. It’s called symbiogenics: the study of fungi bonding with plants to create a mutually beneficial relationship. Scientists at the University of Washington, where the work is being done, are calling it: “a breakthrough”. Biologist and forests researcher Regina Redman is a member of the team.

REDMAN: The approach we're taking is actually quite a very simple one. Plants and natural ecosystems have associations with various microbes. And, the class of microbes that we’re interested in we call Class Two fungal endophytes. So it’s a microscopic fungus. It resides within the native plants that are able to, because of the presence of that fungus, thrive in very high stress habitats. And, we’re able to confer salt tolerance, temperature tolerance, drought resistance, simply by colonizing plants that are of interest.

GELLERMAN: So, you take these fungi and stick them on the rice or the plant and voila?

REDMAN: Yes. They get colonized and then you start seeing the positive benefits immediately. In rice, for instance, you get the growth response where you get roots and shoots coming out much larger and longer than the non-symbiotic counterpart.

GELLERMAN: So what is it in the fungus that is helping the rice plant survive and thrive?

REDMAN: Well, we don’t know the exact mechanism, but we do know that when plants are symbiotic, they seem to be much more metabolically efficient. That is they seem to grow larger, use less water.

GELLERMAN: How much faster can rice with fungi grow?

REDMAN: Well, in the seedling stage, within 24 hours, you’re looking at a three-fold increase in size. Applying this into a field situation would really be beneficial, because if a rice seed can put down its roots very quickly, and then it puts up a shoot, it is able to, under that paddy condition, anchor itself in the soil where it can photosynthesize and, you know, really get going and take off.

GELLERMAN: And so, does it affect the food value of the plant? Do you get rice that is as rich and nutritious?

REDMAN: Well, the unique property also of this class of endophytes is it only colonizes the vegetative tissue, so it’s not in the embryo, it’s not in the seed. So it doesn’t impact the crop.

GELLERMAN: It’s just regular rice.

REDMAN: It’s regular rice. We’ve been able to repeat the process in other agricultural plants as well - wheat, tomatoes and turf grass.

GELLERMAN: Well, the plant is benefiting, so what does the fungus get out of this relationship?

REDMAN: Well, this type of fungus is rather sensitive - it really cannot survive outside of the plant. You’ll find that the fungal endophyte is almost non-existent in the surrounding soil.

GELLERMAN: So somehow the plant is getting a benefit from the fungus, but it’s not genetic, it’s not altering the plant’s structure.

REDMAN: What’s happening if you’re really thinking about it is you’re taking two separate genomes and putting them together, doing their communication back and forth that it allows for this type of beneficial effects that we see. We know that on a molecular level, symbiotic plants turn on a lot of different genes, and turn off a lot of different genes, if it’s under stress or not, compared to the non-symbiotic counterparts.

GELLERMAN: How long has this symbiosis, this symbiotic relationship, been going on between fungus and plants?

REDMAN: Well, we think this communication is quite old. Plants have been symbiotic for around 400 million years, and may have been important for the movement of plants onto land.

GELLERMAN: Wow! You know, we’re seeing this awful, disastrous drought in East Africa; millions of people are starving. Could your research help them?

REDMAN: Yes, I think our research would do exactly that. This is a very simple technology. It doesn’t require a bunch of chemicals. There’s no GMO component of it, and really we can see the results within a growing season.

GELLERMAN: Well, how far off are we from taking this out of a greenhouse and into a field are you?

REDMAN: Well, we’re right there, we’re good to go. We worked for several years, generating the technology to be able to effectively colonize, in this case, rice, on an industrial level.

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