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Plant Root Bacteria

Airdate: April 4, 2017
Like the human gut, plants have a tight relationship with the bacteria that live at their roots. Researchers at Northern Arizona University have found when plants were provided with growth-promoting rhizobacteria, organisms known for their root colonizing ability, vegetable and grain yields increased 20 to 45 percent, and even more so for plants grown in drought conditions. NAU doctoral student Rachel Rubin of the Center for Ecosystem Science and Society will tell us more about her research.

Guests:
  • Rachel Rubin - NAU doctoral student
Category: Science

Keywords: Northern Arizona University, plants, bacteria,

View Transcript
TED SIMONS: RESEARCHERS AT NORTHERN UNIVERSITY HAVE FOUND A WAY TO INCREASE VEGETABLE AND GRAIN YIELDS BY INTRODUCING BACTERIA. RESULTS SHOW GREATER YIELD SHOWN IN DROUGHT CONDITIONS. TO EXPLAIN ALL OF THIS IS NAU RACHAEL RUBEN AT THE CENTER FOR ECOSYSTEM SCIENCE AND SOCIETY. WELCOME TO ARIZONA HORIZON.

RACHAEL RUBEN: THANK YOU FOR HAVING ME.

TED SIMONS: THIS IS FASCINATING. I HAVE NO IDEA WHAT THIS IS ALL ABOUT HERE. IN GENERAL, SOIL-BORNE BACTERIA, HELPING --

RACHAEL RUBEN: PLANT GROWTH PROMOTING A RISE OF BACTERIA. A MOUTHFUL. A BACTERIA THAT LIVES IN AND AROUND PLANT ROOTS SO THEY CAN LIVE INSIDE THE ROOTS OR ON THE ROOT SURFACE OR ON THE SOIL SURROUNDING THE PLANT ROOT. AND THEY'RE A SPECIAL TYPE OF SYMBIOSIS CALLED MUTUALISM. THAT MEANS IT'S A MUTUALLY BENEFICIAL RELATIONSHIP BETWEEN THE PLANTS AND THE BACTERIA.

TED SIMONS: THEY'RE COOPERATING. THEY DON'T HAVE TO COOPERATE, DO THEY?

RACHAEL RUBEN: THEY DON'T HAVE TO, THEY DON'T ALWAYS. BUT IN THIS CASE, WE'RE LOOKING AT THE PLANT HAS SOMETHING THAT THE BACTERIA NEEDS AND VICE VERSA. THE BACTERIA ARE EATING OFF OF THE ROOTS AND FEEDING OFF OF THE SUGARS AND THE CARBOHYDRATES THAT ARE EXUDED AMONG THE PLANT ROOTS. FOR EXCHANGE OF A PLACE TO LIVE, THEY CAN FORGE THE NUTRIENTS MORE EFFECTIVELY AND PRODUCE BIOFILMS THAT RETAIN WATER DURING DROUGHT, FOR EXAMPLE.

TED SIMONS: EXPLAIN THAT. THE FASCINATING THING IS THIS WORKS. THE IDEA IS THAT IT WORKS IN DROUGHT CONDITIONS. THAT'S BIG STUFF. HOW DOES THAT WORK?

RACHAEL RUBEN: IT'S REALLY ENCOURAGING. WE'VE KNOWN ABOUT VARIOUS FUNCTIONS THAT THE BACTERIA CAN DO FOR PLANTS SUCH AS PROVIDING NUTRIENTS IN FORMS OF DISEASE CONTROL. BUT THE ABILITY TO HELP PLANTS COPE WITH EXTREME EVENTS SUCH AS DROUGHT IS A RELATIVELY NEW HORIZON. THAT'S WHY I WANTED TO CAPITALIZE ON THIS ANALYSIS. WE LOOKED AT 52 STUDIES CONDUCTED ALL AROUND THE WORLD. NOT ONE WAY THAT THE BACTERIA HELPS TO PLANT -- IT'S VARIED. SO THIS IS THE COOL WAY WE WERE ABLE TO AGGREGATE ALL OF THE STUDIES AND GET A GENERAL IDEA OF HOW EFFECTIVE WE CAN EXPECT THEM TO BE.

TED SIMONS: IT PROMOTES GROWTH, PROTECTS AGAINST PATHOGENS, THESE SORTS OF THINGS. IT'S A COOPERATIVE RELATIONSHIP, ISN'T IT.

RACHAEL RUBEN: DEFINITELY. A WONDERFUL THING ABOUT NATURE. NOT ALWAYS BEAUTIFUL BUT SOMETIMES IT WORKS OUT.

TED SIMONS: SOIL IN GENERAL, YOU HAVE IRRIGATION, ARTIFICIAL SELECTION. YOU HAVE FERTILIZERS, YOU HAVE ALL OF THAT STUFF OUT THERE. THAT DEGRADES THE SOIL TO A CERTAIN EXTENT AND DOES GET ALL OF THE HELP THEY CAN GET.

RACHAEL RUBEN: ALL OF THOSE PRACTICES WHILE THEY INCREASED YIELDS, WE WORRY THAT WE MIGHT HAVE A NEGATIVE IMPACT ON SYMBIOSIS. SO EXTENSIVE PESTICIDE AND FERTILIZER USED IN CULTURES, THEY CAN DEGRADE THE SOIL SO THAT IT'S NO LONGER PRODUCTIVE. SO THIS -- THIS IDEA OF USING MICROBES TO REINVIGORATE SOIL THAT'S DEGRADED IS WHAT WE'RE GOING FOR. WE'RE LOOKING AT AREAS THAT ARE NO LONGER PRODUCTIVE AND MAYBE WE CAN REINSTATE THE MICROBES WHERE THEY'RE NEEDED THE MOST.

TED SIMONS: IS THIS WITH ALL PLANTS? CERTAIN PLANTS WORK BETTER THAN SOME PLANTS? THEY JUST DON'T COOPERATE. IT'S JUST NOT GOING TO WORK.

RACHAEL RUBEN: EVERY SITE IS DIFFERENT. EVERY STUDY IS DIFFERENT. IT'S COOL THAT WE DID FIND THIS IS A PRETTY GENERALIZABLE EFFECT ACROSS ALL PLANTS. THERE WAS -- THEY DO SEEM TO BE A LITTLE MORE EFFECTIVE FOR WORM SEEDS AND GRASSES SUCH AS CORN AND SORGHUM BUT LESS EFFECTIVE ON RICE, WHEAT, PLANTS.

TED SIMONS: LESS EFFECTIVE NOW. THERE COULD BE STUFF OUT THERE THAT WE'RE NOT AWARE OF.

RACHAEL RUBEN: NEW ONES ARE BEING DISCOVERED. A NEW FIELD. ABOUT 15 YEARS IN THE MAKING.

TED SIMONS: IT STRIKES ME THIS IS SOMEWHAT SIMILAR TO BACTERIA IN THE GUT. AND WHAT WE'RE LEARNING ABOUT THAT AND, YOU KNOW, PROBIOTICS AND ALL THAT BUSINESS THAT I DON'T UNDERSTAND EITHER. BUT IT SOUNDS SIMILAR.

RACHAEL RUBEN: IT IS SIMILAR IN CONCEPT. JUST LIKE HUMANS, PLANTS CO-EVOLVED WITH THEIR MICROBIOME. IT'S VERY IMPORTANT FOR THEIR SURVIVAL. THIS STUDY ILLUSTRATES HOW IMPORTANT THEY ARE. BECAUSE WHEN WE ADD THE BACTERIA IN, THE PLANTS REALLY FLOURISHED. THERE'S A VISUAL WITH THAT.

TED SIMONS: IS THERE REALLY? I'M NOT AWARE OF THAT. IF THERE IS, TAKE A LOOK. IF NOT, WE'LL IMAGINE IT. NOT SURE IF THAT'S OFFICIAL. HOW IS THE HYPOTHESIS AND WHO DECIDED, HEY, I WONDER IF THIS WILL WORK?

RACHAEL RUBEN: THIS IS -- I KIND OF SAW A VOID IN THE LITERATURE ON THIS TOPIC. THERE'S A LOT THAT WE KNOW ABOUT FUNGI, BUT WE KNOW A LOT LESS ABOUT BACTERIA. THERE'S A LOT OF STUDIES BEING CONDUCTED ON THIS TOPIC. I WANTED TO GET A SENSE OF HOW -- WHAT'S THE GENERAL CONSENSUS. BECAUSE EVERY STUDY IS SO DIFFERENT. EVERYBODY WILL BE ABLE TO READ ALL OF THIS SCIENCE.

TED SIMONS: SURE, NO KIDDING. WE HAVE 30, 45 SECONDS LEFT HERE. WHAT DOES ALL OF THIS THING -- THIS IS A BIG DEAL FOR YOU. THIS IS GROUND BREAKING STUFF YOU DO HERE. BUT WHAT DOES IT ALL MEAN?

RACHAEL RUBEN: IT MEANS THAT THIS IS ENCOURAGING THAT IN THE AREAS OF THE WORLD THAT NEED THIS THE MOST THAT BACTERIA COULD REALLY HELP THEM SURVIVE BETWEEN 20% AND 40% INCREASE IN GROWTH IS WHAT WE FOUND. AND THE EFFECT IS GREATER UNDER DROUGHT. SO THIS GIVES ME HOPE ABOUT THE FUTURE OF THE AGRICULTURE AND I HOPE WE CAN HAVE MORE EFFORTS TO IMPROVE A LOT OF DIVERSITY IN THIS METHOD.

THIS GIVES A LOT OF PEOPLE HOPE. THIS IS GOOD STUFF. CONGRATULATIONS, CONTINUED SUCCESS. WE WISH YOU LUCK. APPRECIATE IT. THAT IS IT FOR NOW. I'M TED SIMONS, THANK YOU SO MUCH FOR JOINING US.