Move over Arabidopsis, there’s a new model plant in town

Bond LSC researchers showed for the first time ever that a grass, Setaria viridis, can receive 100 percent of its nitrogen needs from bacteria  when associated with plant root surfaces. This grass will now serve as model for research into biological nitrogen fixation that could benefit crop development. | Photo by Roger Meissen, Bond LSC

Bond LSC researchers showed for the first time ever that a grass, Setaria viridis, can receive 100 percent of its nitrogen needs from bacteria when associated with plant root surfaces. This grass will now serve as model for research into biological nitrogen fixation that could benefit crop development. | Photo by Roger Meissen, Bond LSC

By Roger Meissen | MU Bond Life Sciences Center

As farmers spend billions of dollars spreading nitrogen on their fields this spring, researchers at the University of Missouri are working toward less reliance on the fertilizer.

Less dependence on nitrogen could start with a simple type of grass, Setaria viridis, and its relationship with bacteria. The plant promises to lay groundwork for scientists exploring the relationship between crops and the fixing nitrogen bacteria that provide them the nitrogen amount plants need daily.

“In science sometimes you have to believe because we often work with such small microorganisms and DNA that you cannot see,” said Fernanda Amaral, coauthor and MU postdoctoral fellow at Bond Life Sciences Center. “Before this research no one had actually proved such evidence that nitrogen excreted by bacteria could be incorporated into plants like this.”

Fernanda Amaral, coauthor and MU postdoctoral fellow at Bond Life Sciences Center. | Photo by Roger Meissen, Bond LSC

Fernanda Amaral, coauthor and MU postdoctoral fellow at Bond Life Sciences Center. | Photo by Roger Meissen, Bond LSC

Biological Nitrogen fixation — where diazotrophic bacteria fix atmospheric nitrogen and convert it to ammonium — provides a free way for plants to alter and absorb the nutrient. Farmers have long known that legumes like soybean fix nitrogen due to the symbiosis with bacteria in the soil through development of nodules on their roots, but since grasses like corn and rice don’t form this specialized structures that relationship has been trickier to explore.

Yet in fact, this team’s experiments showed the grass Setaria viridis received 100 percent of its nitrogen needs from the bacteria Azospirillum brasilense when associated with plant root surfaces.

“I believed in these bacteria’s ability, but I was really surprised that the amount of nitrogen fixed by the bacteria was 100 percent,” Amaral said. “That’s really cool, and that nitrogen can make so much of a difference in the plant.”

Worldwide farmers used more than 100 million tons of nitrogen on fields in 2011, according to the United Nations Food and Agriculture Organization. In the same year, the U.S. alone produced and imported more than $37 billion in nitrogen.

This grass can serve as a simple model for research, standing in for grass relatives such as corn, rice and sugarcane to explore a similar relationship in those crops. This research, “Robust biological nitrogen fixation in a model grass–bacterial association,” was published in the March 2015 issue of The Plant Journal.

 

A nutrient, a nuclear reactor and a model plant

Proving that this grass actually uses nitrogen excreted from the bacteria took some clever experiments, a global collaboration and a nuclear reactor.

MU researchers in the lab of Gary Stacey, a Bond LSC investigator, partnered with scientists in Brazil and at Brookhaven National Laboratory in New York to find a robust plant model system.

They screened more than 30 genotypes of Setaria viridis grass, looking for a strong nitrogen fixing response when colonized with three different bacteria strains. They germinated the seeds in Petri dishes and inoculated those three days after germination with a bacterial solution. Then plants were transplanted into soil containing no nutrients. By eliminating nitrogen in the soil, the scientists were able to make sure that the bacteria was the only source of nitrogen for plant.

The team settled on Azospirillum brasilense bacteria, which has been used commercially in South America to improve crop plant growth. It colonizes the surface of the roots and showed the greatest amount of plant growth when associated with plant roots.

Proving that the bacteria truly fixed the nitrogen used by the plant, required exposing plants to radioactive isotopes at Brookhaven National Laboratory. That began with Nitrogen 13, an unstable radio isotope that showed exactly where and how quickly this nutrient was taken up from the bacteria.

A radio tracer chamber at Brookhaven National Laboratory was needed to test if Setaria viridis actually used nitrogen produced by the bacteria. The scientists allowed only one leaf to contact the radioactive nitrogen, so they could truly tell if it was being used. | Photo provided by Fernanda Amaral

A radio tracer chamber at Brookhaven National Laboratory was needed to test if Setaria viridis actually used nitrogen produced by the bacteria. The scientists allowed only one leaf to contact the radioactive nitrogen, so they could truly tell if it was being used. | Photo provided by Fernanda Amaral

“Nitrogen 13 is really sensitive matter with a half-life of less than 10 minutes, and we first thought there wouldn’t be that much nitrogen fixed by the plant,” Amaral said. “We administered Nitrogen 13 only on the roots, quickly scanned the samples and calculated how much of the nitrogen the plants assimilated based on the decay analysis of the tracer.”

This experiment, paired with several others, showed that this model grass truly incorporated the nitrogen released by the bacteria and metabolizes it in several components.

 

Model (plant) citizen

But why does a type of grass that doesn’t produce food matter so much?

The answer is time and simplicity.

“Corn is really good at responding to bacterial inoculation, but it’s very big and takes a long time to produce seeds and also the genome is complex,” said Beverly Agtuca, an MU Ph.D. student who worked on the study. “Setaria viridis is a small plant that can produce a lot of seeds faster, has a pretty simple genome and can serve as a model for research.”

That makes it perfect to explore how the plant actually uses its bacterial partners, and labs around the world are already using this plant model for research.

For the Stacey lab, the next step is to pinpoint the gene in the model grass that makes this possible.

“We want to identify the genes responsible for the interaction between plant and bacteria and meanly the ones involved with the nitrogen uptake,” Fernanda said. “We hope that will allow us to improve plant growth based on the gene to further study.” We believe that our findings can stimulate others studies at this area, which seems to be a promise plant friendly way to apply for promoting a sustainable agriculture, especially to crop systems including bioenergy grass.

Amaral and Agtuca work in the lab of Gary Stacey at Bond LSC. Stacey is a Bond LSC investigator and a Curators Professor of Plant Sciences in the College of Agriculture, Food and Natural Resources at the University of Missouri. Collaborators included researchers at Brookhaven National Laboratory, State University of New York, Federal University of Paraná in Brazil and Federal University of Santa Catarina in Brazil.

Funding for this project came from the National Institute of Science and Technology- Biological Nitrogen Fixation, INCT-FBN, the Brazilian Research Council, Ciência Sem Fronteiras Program, The Department of Energy and SUNY School of Environmental Science and Forestry Honors Internship Program.

Forest at your fingertips: smartphones enhance fieldwork

An MU student uses his cell phone while in Costa Rica. | Photo by Jack Schultz, Bond LSC

An MU student uses his cell phone while in Costa Rica. | Photo by Jack Schultz, Bond LSC

By Jack Schultz | Director of MU Bond Life Sciences Center

“Fieldwork” means many things to researchers, but in the past it often meant working without easy access to communication.

Now cell phones allow my students visiting the La Selva Biological Station in the lowland rainforest of Costa Rica to remain connected.

While our science and journalism majors learn to report on biological research, I find that I can be replaced. As an experienced biologist who has taught and worked in the Costa Rican tropics for some time, I normally serve as a biology resource. After all, our journalism students have little or no science background.

Yet, as students interview scientists working in a rainforest, learn about the forest’s biology and write about it daily, they now can go online to find the answer. Everything from ecological theory to species lists for our forest site are accessible to any student with a WiFi connection. Fortunately, the biological station has good WiFi service.

While I need to prompt searches to help students know what to look for, the answer to “what was that animal?” is just a hyperlink away. I’m carrying a bulky field guide to the birds, but most often find myself online, checking my own recollection of animals, plants, and facts and figures.

Students return from the forest with evidence of what they’ve seen, which is much better than a hand-waving verbal description. Group meals are eaten with one hand on the phone and the other on a fork. The day’s plans can be refined at breakfast by checking the weather forecast for our rainforest site.

Any good journalist acquires as much background as possible before an interview. Our students can do that in short order by visiting websites of the people we meet in the field. Over several days, they can refine their knowledge and questions to get the most from conversations with researchers. When a term or concept arises in interviews, clarification is right there on the phone.

Cell phone use goes well beyond fact checking.

Paper maps melt in the rain, but the students took photos of the maps we were given and use their cell phones to find their way on the forest trails. Many actually take notes on their phones, and some compose essays there. The improving quality of cell phone cameras produces excellent pictures to post with blogs and articles. Some of the students are producing photos that rival the quality of photos I take with my bulky DSLR. And the videos they produce are high quality and easy to edit.

While computers and tablets are the instruments of choice for uploading larger essays, cool observations can go direct from a cell phone to Twitter, Instagram or even Facebook. And posting to personal Facebook pages keep family and friends updated on each day’s adventures. Everyone in our group is in close contact with home, even if home is in Saudi Arabia (in one case).

While I will admit to feeling, at first, that cell phones could ruin the fieldwork experience, my perspective has changed to value it as a professional tool and not just a personal toy.

Now I’ll be in line for a cell phone upgrade when I return home.

The Curious Case of Inflammation: One Lab’s Mission to Put the Pieces Together

White coat, dark room. Jean Camden, a senior technician in the Weisman lab, reviews salivary gland and brain tissue samples for research on inflammation. | Photo by Paige Blankenbuehler, Bond LSC

White coat, dark room. Jean Camden, a senior technician in the Weisman lab, reviews salivary gland and brain tissue samples for research on inflammation. | Photo by Paige Blankenbuehler, Bond LSC

By Paige Blankenbuehler | MU Bond Life Sciences Center

There’s a criminal on the loose, striking every day. Millions fall victim, but there’s still no way to stop it. And, in all likelihood, you have been hurt by it.

If inflammation is an unsolved criminal case of the last three decades, then Gary Weisman has been the detective. He’s certain there’s an accomplice — perhaps many — that may be triggering the discomfort.

The Bond Life Sciences Center investigator is slowly revealing what makes inflammation tick and what makes it strike. Each epiphany brings another question. He’s certain there’s a way to prevent negative effects of unsolved inflammation.

Bond LSC investigator and MU professor of biochemistry, has been studying the ins-and-outs of inflammation for the last 30 years. | Photo by Paige Blankenbuehler, Bond LSC

Bond LSC investigator and MU professor of biochemistry, has been studying the ins-and-outs of inflammation for the last 30 years. | Photo by Paige Blankenbuehler, Bond LSC

Weisman has dedicated his career to understanding the micro-processes behind inflammation. He’s become so specialized that his techniques can be as hard to crack as the case itself.

“I would not ask anyone to explain what I do,” Weisman says. Nonetheless, he’s been able to divide the process of inflammation into two categories: components that repair the body and components that lead to its destruction. This will help find inflammation’s many accomplices to figure out why humans work, and what their bodies do when they don’t work so well.

“I am interested in the meaning of life,” Weisman says. “Life has become simpler for me because the scientific method carries everywhere. I’ve become aware of how simple we are as a machine.”

 

Criminal or just misunderstood?

Most criminals adopt patterns, but inflammation stands as a signpost for mysterious, underlying problems.

Its effects are usually localized: an arm, a joint, the brain or a gland. You feel a temperature spike then the skin reddens in a part of your body. Later still, the skin tightens and pain comes at a snail’s pace.

Not even cells are safe. Inflammation even strikes on the molecular level.

But really, inflammation can be a good thing. It’s part of the immune system’s bag of tricks to signal the body to bring in reinforcements to fight off the invasion. Normally, inflammation corrects a physical problem, but if it is not successful in repairing a problem, inflammation can become chronic and accelerate tissue destruction.

Just like in an episode of CSI, Weisman puts the pieces of the inflammation puzzle together in his office by applying the expertise of Laurie Erb, Jean Camden and Lucas Woods — all donned in white lab coats, eyes pressed to the microscope examining evidence and building molecular evidence in the case.

The MU associate professor of biochemistry and his team have become a sort of grant-wielding wizards to sustain his pursuit of inflammation triggers. National Institutes of Health grant awards have sustained his lab for decades. The funding has come from varied sources such as the MU Food for the 21st Century Program, the Bond LSC, the Bright Focus Foundation, the American Heart Association and the Cystic Fibrosis Foundation. In recent years, research funding for Alzheimer’s disease and Sjogren’s syndrome (a disease of the salivary gland that causes dryness) have contributed, too.

But the funding source doesn’t matter because inflammation is the tie that binds.

Jean Camden processes samples under the Weisman lab's microscope. | Photo by Paige Blankenbuehler, Bond LSC

Jean Camden processes samples under the Weisman lab’s microscope. | Photo by Paige Blankenbuehler, Bond LSC

Advancements, like recent mapping of the human genome, have moved his work forward to understand inflammation’s complexity. Each experiment he completes fills in another blank slate in the “human owner’s manual.”

“As humans, we’re so intent on the fact that we’re superior to all, but really we’re not,” Weisman says. “With the Human Genome project, we’ve come to understand that all living things have similar designs … we are on the verge of finding revolutionary solutions to preventing or reversing human diseases.”

 

A receptor all our own

One specific player in the body’s immune system has kept Weisman’s attention for most of his career. The P2Y2 protein is a nucleotide receptor, and his lab team members affectionately refer to it as “our receptor.”

Nucleotide receptors are regulatory molecules in red blood cells. What they regulate is nuanced, mostly undetermined and of great interest to scientists. Answering that question has become Weisman’s wheelhouse.

The body manufactures 15 different types of nucleotide receptors, all similar in construction, but each are believed to have subtly different functional roles. It’s as if Weisman and his lab is on the case of a highly organized crime ring.

“Our receptor is mainly present when inflammation occurs, and we’re trying to figure out its role in a variety of diseases,” Weisman says.

The P2Y2 receptor has been observed in Alzheimer’s patients, along with a plaque build-up in the brain, and the receptor was suspected of playing a role in the disease’s progression.

Weisman and his colleagues found that the deletion of the P2Y2 receptor in a mouse model of Alzheimer’s disease accelerates progression of plaque build-up, neurological symptoms and death. This suggests that the receptor has anti-inflammatory effects rather than being “guilty by association” with the tissue-destructive aspects of inflammation.

“It’s like I have this 30,000-piece jigsaw puzzle in front of me that I have to put together,” Weisman says. “What’s the difference between you and me? As a machine, surprisingly very little.”

This simplicity drives Weisman to continue solving the mysteries of inflammation and search for its underlying chemical processes. By understanding the body’s chemical reactions, he believes treatments can be developed to focus the immune system on repairing damaged tissues.

Through studying his receptor, Weisman is breaking up inflammation’s crime ring.

Unlocking plants’ metabolic thermostat — award-winning LSW posters

Unlocking plants’ metabolic thermostat — award-winning LSW posters

Matthew Salie would like to see chubbier plants.

“You’ve probably never really seen a fat plant before, right?” said Salie, a fourth year MU graduate student in biochemistry­. “Humans, we make plenty of extra fat and store that as energy. But plants don’t really need to do that — they make just as much as they need, and that’s about it.”

Salie studies plant metabolism with Bond LSC researcher Jay Thelen, an associate professor of biochemistry. He’s one of 25 winners honored for research presented during Missouri Life Sciences Week 2015.

The Thelen lab looks for ways to increase the amount of vegetable oil that crops such as corn and soybean can produce. Salie focused on an enzyme that is the first step in the pathway to producing fatty acid in plants.

The idea was that if he could reduce metabolic limits at the beginning of the process, then the downstream production of oil would increase.

“I found these new proteins that no one has ever really studied before,” Salie said. “As I started to look into them over the last year or two, it turns out that they actually seem to incorporate themselves into the enzyme and slow down it’s activity.”

Four separate proteins normally combine to form the functional enzyme, but the new proteins Salie identified mimic those components and can take their place, like a cuckoo bird replacing another species’ eggs with its own. The more mimics that replace proteins, the fewer functional enzymes the plant produces, which means less oil.

It’s a simple, nuanced way for the plant to fine-tune the production of fatty acids.

“Instead of being an on-off switch, it’s more like a thermostat,” Salie said. And if he can adjust that thermostat in a plant, it should start packing on the pounds.

Although Salies work was only recently submitted for publication, it’s already receiving recognition. His poster, “The BADC proteins — a novel paradigm for regulation of de novo fatty acid synthesis in plants,” won first place in the Molecular and Cellular Biology category during the Life Sciences Week poster competition in April.

Salie relished the opportunity to share his findings with researchers and non-scientists alike.

“It’s a great experience, because it helps you realize what’s really important about the work that your doing,” he said. “It also really encourages you to work harder. It’s like, ‘Wow, this is actually meaningful stuff!’ which can be hard to see when you’re working 60 or 70 hour weeks at the lab, just sitting there by yourself.”

Salie was among more than 300 students who presented their research during the 31st annual Life Sciences Week poster sessions.

 

The winners in each of the five categories are:

  • Molecular and Cellular Biology
    • Matthew Salie, Matthew Muller, Stephanie Bowers
  • Organismal Biology
    • Miqdad Dhariwala, Ryan Sheldon, Carine Collins
  • Genetics, Evolution and Environment
    • Julianna Jenkins, Nathan Harness, and a tie for third between Sharon Kuo and Susheel Bhanu Busi
  • Life Science and Biomedical Engineering Technologies and Informatics
    • Jamie Hibbard, Hang Xu, Brittany Hagenhoff
  • Social and Behavioral Sciences
    • Vaness Cox and Ian George tied for first place

Undergraduate winners are Vincent Farinella, James Mrkvicka, Anette van Swaay, Romanus Hutchins, Dallas Pineda, Kelsey Boschert, Anthony Onuzuruike, Clare Diester, Adam Kidwell and Sean Rogers.

Honorable mention:

  • Social and Behavioral Sciences
    • Undergrad Honorable Mention – Kelsey Clark
    • Undergrad Honorable Mention – Louie Markovits
  • Genetics, Evolution, and Environment
    • Grad Honorable Mentions: Megan Murphy (Schul) and Amanda Smolinsky (Holliday)
    • Undergrad Honorable mention: Anthony Spates (Holliday)
  • Organismal Biology
    • Grad Honorable Mention: Kathleen Pennington
    • Grad Honorable Mention: Kasun Kodippili
    • Grad Honorable Mention: Christopher Tracy
    • Undergrad Honorable mention: Chelsie Todd
    • Undergrad Honorable mention: Holly Doerr
    • Undergrad Honorable mention: Zeina Zeida
  • Molecular and Cellular Biology
    • Grad Honorable mention, Khalid Alam [Burke lab]
    • Grad Honorable mention, Zhe Li [Sarafianos lab]
    • Undergrad Honorable mention: Vincent Markovitz [Guo lab]

Additional prizes were awarded for communication prowess and poster design chops.

For photos of some of this year’s winner, check out this Flickr album