Paula McSteen

Beyond counting: computer science partnership helps speed up plant science experiments

May 12, 2021 By Lauren Hines in Research Tags: BIPS, computer science, high-throughput phenotying, plant science

Janlo Robil, graduate student in the Paula McSteen lab, came up with the GrasVIQ project after he finished a project that required him to count hundreds of plant leaf veins. | photo by Lauren Hines, Bond LSC

By Lauren Hines | Bond LSC

It’s not surprising that researchers feel discouraged when pursuing projects that involve plant leaf vein density analysis. Manually counting individual leaf veins and measuring their density to understand how nutrients are transported in plants can take weeks of tedious work.

That’s how Janlo Robil was feeling when he was working on a maize leaf project while rotating through the Paula McSteen lab in 2016 in Bond LSC.

Now, researchers can cut that time down to just minutes.

As part of the Bioinformatics in Plant Sciences (BIPS) program, undergraduate and graduate students in plant sciences and computer science have come together to create the first phenotype image analysis system for monocot plant leaf veins called, GrasVIQ.

The GrasVIQ software can process photos of grass leaves, automatically detect and count vertical grass leaf veins and calculate various quantitative measurements such as vein density, width and separation. These measurements help analyze leaf vein network patterns.

“The time that you use for collecting data, you can already use for analysis,” said Janlo Robil, head of the project and graduate student in the McSteen lab. “It will also help you in your decision about the direction of your research because the faster you get the data, then the better idea you have if you still need to pursue this or not.”

The project was spurred by Robil in 2017 when he went to a seminar by Filiz Bunyak, assistant research professor in the Electrical Engineering and Computer Science Department.

Bunyak was presenting her group’s interdisciplinary image processing and computer vision research, including their work on plant phenotype analysis. Robil got the idea to apply it to plant leaf veins.

“It started from a simple question,” said Ke Gao, co-author and graduate student in the Electrical Engineering and Computer Science Department. “Can we help them do their analysis faster with repeatable quantified results? We were hopeful we could use our previous experiences in plant image analysis to help Janlo and his lab conduct their analysis more efficiently.”

However, the project was on hold until 2019. Robil simply didn’t have the time or manpower for this project until he heard about the BIPS program.

“I think [the BIPS program is] a very good way of promoting interdisciplinarity in research,” Robil said. “Had I not asked the computer science people to collaborate with me, I would still be manually counting veins right now, and not using software to quantify veins more quickly. I think interdisciplinarity can move science forward and faster, literally.”

The software can identify the vertical veins with 95% accuracy and 92% accuracy for transverse veins when compared to the manual quantification.

“Without any doubt, we believe that the software can do a better job by just the rate of it,” Robil said.

The GrasVIQ phenotyping image analysis software can classify and quantify stained veins of grass and corn leaves. doi.org/10.1111/tpj.15299

While the software saves plant science researchers time and energy, it also provides computer science students something as well.

“Collaborating with plant scientists gives us the opportunity to leverage our expertise in engineering, algorithm development, and mathematical models to contribute to the solution of a real-world problem,” Gao said.

BIPS pairs undergraduate and graduate students from plant sciences and computer science together to work on a project. For undergraduate Claire Neighbors in the McSteen lab and computer science undergraduate Michael Boeding, this was their first published paper.

“It’s super exciting,” Neighbors said. “It feels good like all my hard work meant something.”

Neighbors was the one who had to create the images and do the manual counting to compare to the software’s counting. She said the process took her months.

“It was worth something so that we could make this software valid,” Neighbors said. “Someone had to put in the hours to be able to make those ground truths to show that this software works. So, it feels really good that I was able to contribute something.”

While the software has much to offer, the researchers believe it could be better. Robil thinks vein classification can be improved using machine learning even though the software achieves a detection accuracy of more than 90% for vertical veins.

The current software is designed to be used by scientists and does not have a very friendly user interface. Building a better user interface and further improving the analytics using machine learning approaches are future goals for Gao. GrasVIQ will enable generations of training data for these machine learning-based improvements.

Nonetheless, the software provides an escape from endlessly counting veins.

“We learned how to quantify the veins quickly, but like a year from now, that isn’t going to be what’s taking us months to do,” Neighbors said. “It’s going to be figuring out why this gene made the veins look weird or produced less or thinner, thicker, which is going to make things more efficient in the future.”

More information about the project can be found in, “GrasVIQ: An Image Analysis Framework for Automatically Quantifying Vein Number and Morphology in Grass Leaves.” The paper was published on April 29 in The Plant Journal. The study was done by Janlo Robil, Ke Gao, Claire Neighbors, Michael Boeding, Francine Carland, Filiz Bunyak and Paula McSteen. The Bioinformatics and Plant Sciences (BIPS) program is funded under the National Science Foundation, Cellular Dynamics and Function MCB-1818312 to David Mendoza-Cozatl (University of Missouri, Columbia).

Lab explores link between genetic differences and domestication in kale

April 28, 2021 By Becca Wolf in Research Tags: Brassicales, gene expression, kale

Tatiana Arias and Chad Niederhuth studied the plant, kale, in this publication. | “Kale” by photofarmer is licensed under CC BY 2.0

By Becca Wolf | Bond LSC

It is said that variety is the spice of life.

When it comes to kale, much of that variation derives from domestication, and genetic differences that evolved over thousands of years resulted in different color of leaves, nutritional value, and habit and length of growth.

Understanding the links between traits and genes could one day help plant scientists create better vegetables for us.

Eight years ago, Tatiana Arias from the Chris Pires lab and Chad Niederhuth from the John Walker and Paula McSteen lab at Bond Life Sciences Center came together to research leaf differences in this species, Brassica oleracea. Brassica oleracea includes many foods from the vegetable aisle from the grocery store like kale, cabbage, and broccoli.

“In general, people do these types of studies to narrow down some specific genes, but we tried to find a bunch of different genes that could serve different purposes in the future for basic science and developmental biology studies, but also for more applied work in crop sciences,” Arias said.

She and Niederhuth’s broad approach looked at genes that they thought could have been selected during domestication of kale. As humans farmed these leafy greens over millennia, they selected for plants that grew more upright with leaves we liked to eat, developed more ornate foliage and flowered later, differentiating kale from its sisters like broccoli and cauliflower where the flowers were the valued food product.

They compared three morphotypes of Brassica oleracea plants: kale, cabbage, and TO1000 — a specific kale line.

“We brought the evolutionary history of how Kale was domesticated from the other Brassica oleracea morphotypes. Tatiana is really good at the microscope and doing really detailed sections of different parts of the plant as they’re growing,” Chris Pires said. “They sequenced using next gen sequencing, which I’d suppose you’d call it old next gen or postmodern sequencing since it’s been so long.”

While sequencing RNA, the labs found thousands of genes expressed in these different vegetable lines.

“I am a classically trained botanist, so for me it was a very new approach to think about genomics for plants,” Arias said.

While the Pires lab handled the RNA sequencing, Niederhuth in the McSteen lab handled the bioinformatics analysis, the mapping of sequence data, and the identification of the differentially expressed genes.

“It was a team effort between Tatiana and I, she was really the expert in studying these different varieties and their morphological differences and she generated a lot of the data,” Niederhuth said. “I brought to that some of my expertise in gene expression data.”

Through their work, Arias and Niederhuth found 3,958 expressed genes that separated kale from cabbage and TO1000. Some of these differences were in genes that regulate vegetative and reproductive transitions — things that create the very different look of cabbage versus kale.

Some genes they found in kale were particularly interesting. These were involved in leaf morphology, plant structure, and nutrition and were expressed differently, allowing them to identify a set of genes that may be important in kale domestication. Those genes would link, for example, to why kale is more upright and cabbage leaves curl into a head or the variation in color of the leaves.

“I didn’t necessarily know what to expect going into it,” Niederhuth said. “It was interesting to see some results that were related to some of the differences in the phenotypes we observed. Before this I had never worked with Brassica oleracea before, it was the first time I was working with genomic data from a species other than Arabidopsis. It helped me begin working with a variety of different species in many ways.”

While this research was conducted over eight years ago, Arias and Niederhuth recently published the findings.

“It’s nice to have one of many projects off my plate, and I’m glad that it’s finally gotten out there,” Niederhuth said. “This is just how life works where people in this career are oftentimes moving and things get set aside. I am glad that after all these years, we’re finally able to come together again and get it finished.”

To read more of Arias’ and Niederhuth’s research, check out the March article published on the Frontiers in Plant Science website titled, “The Molecular Basis of Kale Domestication: Transcriptional Profiling of Developing Leaves Provides New Insights Into the Evolution of a Brassica oleracea Vegetative Morphotype.”

Boron: Exposed

April 22, 2020 By Lauren Hines in Research Tags: boron, plant roots

Assessment of a 18F-Phenylboronic Acid Radiotracer for Imaging Boron in Maize — Figure B is a colorized radiographic image that shows the path of boron in a five-day-old maize seedling. | photo contributed by Alexandra Housh, Michaela Matthes, Amber Gerheart, Stacy Wilder, Kun-Eek Kil, Michael Schueller, James Guthrie, Paula McSteen, and Richard Ferrieri.

By Lauren Hines | Bond LSC

The element Boron, while extremely low in levels, leaves a trail of green and blue radioactive decay as it travels through the veins of plants.

Due to radiotracer technology, this picture of the element’s movement provides this unique insight to what’s going on inside the leaves, stems and roots of plants for the first time ever.

A new collaboration between Bond LSC’s McSteen lab and the MU Research Reactor’s Ferrieri lab led the two labs to present [18 F]-4-FluoropPhenylboronic Acid (FPBA), a radiotracer they designed that can track and visually report on the movement of boron in plants, in a February journal article in the International Journal of Molecular Sciences. The visual tracking was done inside corn.

“It’s the first time anyone has been able to see boron in plants, which is very exciting,” said Paula McSteen, associate professor and researcher at Bond LSC.

The Fifth Element

Boron is an essential micronutrient for plants, but unfortunately, is deficient in soils worldwide. That leads to defects in the roots and shoots of plants, therefore leading to a reduction in crop yields.

“Up to now, there was no way of imaging boron in the plant, which makes it hard because if you could see it somewhere else, like in the cell wall, you would know it has a role there, right?” said Michaela Matthes, postdoctoral scholar in the McSteen lab. “But no one can see it.”

Now, with the equivalent of a PET Scan (Positron Emission Topography) some might receive in a hospital, researchers are able to image and track the movement of boron in live plants to learn where in the plant it’s important and, eventually, how to manipulate it to result in higher crop yields.

You might not think boron would be a controversial topic in the life sciences community, but a longstanding dispute about its importance has been debated for years. The argument is not whether or not the micronutrient is critical to plant development and growth, but where and how it functions. Since there’s such low levels of boron, it’s undetectable. Imaging boron and being able to pick it out will allow a pathway to more direct evidence of its role.

The research study found that the tracer accumulated in the root tip, root elongation zone, lateral root initiation sites and leaf edges in maize.

“So, the accumulation of the tracer basically means there was a signal of the tracer at the root tip, and at the leaf edges, which means boron is there,” Matthes said.

This presence is exactly the kind of direct, visual evidence that supports the argument of the role boron plays in maize growth.

“The other methodologies we looked at would have measured the natural level of boron in the plant, and because that is too low, it is below detection,” Matthes said. “That is why the radiotracer is superior because we are actually adding something to the plant that we then image.”

Micha Matthes — In the McSteen lab, Matthes fills falcon tubes that contain seeds with water, so they can germinate with exposed roots. | photo by Lauren Hines, Bond LSC

Tracking Boron

“When we came here, we were keenly aware of Dr. McSteen’s interest in boron and the challenges of imaging boron, so we started a discussion between our groups about what we could bring to the table with our radiotracer technology,” said Richard Ferrieri, research professor at the MU Research Reactor who came to MU from Brookhaven National Laboratory.

A radiotracer is a chemical compound where a radioactive element is added to whatever a researcher wants to track, which acts as a tag as it moves through the body or plant. Scientists take pictures of its radioactive decay, showing where the element travels and ends up in higher levels.

In this case radioactive fluorine was added to phenylboronic acid (PBA), a compound the plant can easily absorb, which turns PBA into FPBA. FPBA moves exactly like boron in the plant, so it provides an accurate representation of where boron goes and possibly its role.

The Ferrieri lab grew maize hydroponically, in a solution of plant nutrients, under normal lighting conditions. Once they grew to a certain size, they were moved into glass beakers where the roots were submerged in water. A formulation of the FPBA tracer was then added so that the roots could natural absorb the radioactivity.

Using another imaging technique similar to getting an X-ray called, autoradiography, the Ferrieri lab was able to obtain snapshots of the radioactivity inside the plant to see where it accumulated.

“The imaging that we do is giving us information on where the radioactive tracer mimicking boron goes. Having that visual feedback gives us insight about boron’s role in plant growth and development,” Ferrieri said. “I would say in the world of plant biology, this is the first example of chemists sitting down and designing a custom molecular probe to answer some hard, biological questions in regard to boron uptake in plants,” Ferrieri said.

Micha Matthes and Paula McSteen — McSteen and Matthes work together on discovering the roles of Boron in Maize. | photo by Lauren Hines, Bond LSC

What There’s Left to Discover

“Very little is known so far about boron,” Matthes said. “The very basic research question has not been fully answered, and I think it’s fascinating to contribute to that knowledge.”

Researchers were limited in how they could investigate boron’s role without being able to see where boron was in the plant. Matthes said the biggest gap in knowledge in the field of studying boron is whether or not there is an additional role of boron in the plant cell beyond the cell wall.

While there is so little known about boron, researchers aren’t helping themselves due to the lack of method standardization, according to a review written by Matthes, McSteen and Janlo Robil, a Ph.D. candidate in the McSteen lab. When procedures or measurements aren’t consistent across different studies, it makes it hard for other researchers to duplicate experiments and build on existing knowledge.

They also went into evaluating different methodologies investigating boron and how each of them is limited.

“What I think is the best [methodology] is probably a combination of different approaches depending on the question you are asking,” Matthes said.

However, the radiotracer approach can directly locate boron without destroying the plant.

Even though much has been accomplished already, Matthes will keep working towards filling in those gaps.

Photos were used from Assessment of a ¹⁸F-Phenylboronic Acid Radiotracer for Imaging Boron in Maize.

Housh, A.B.; Matthes, M.S.; Gerheart, A.; Wilder, S.L.; Kil, K.-E.; Schueller, M.; Guthrie, J.M.; McSteen, P.; Ferrieri, R. Assessment of a ¹⁸F-Phenylboronic Acid Radiotracer for Imaging Boron in Maize. Int. J. Mol. Sci. 2020, 21, 976.

Coming to a crossroads

February 10, 2020 By Lauren Hines in Faces of Science Tags: Arts and Sciences, plant science

By Lauren Hines | Bond LSC

The scene of the science fair wouldn’t be complete without the paper mâché volcano, the gymnasium full of colorful display boards set up across a floor and the voices of students each giving their own presentations to their parents.

For Janlo Robil — a Ph.D. candidate in plant development genetics who works in the Paula McSteen lab at Bond LSC — his excitement for science and creativity was born in this mix of dioramas, experiments and hypotheses.

That passion has led Robil to a place where his science and art can interact. While his experiments focus on how the plant hormone auxin affects growth, he uses his artistic skills to create figures and translate that science to his editors.

Robil started out as a freelance graphic artist in the Philippines where he’s from — creating logos and company designs. His inspiration comes from “natural things” and “creating shapes from what we already see as natural.”

“What’s nice about being a scientist and an artist is that I always look for art in everything I do in my science,” Robil said.

Using Adobe Illustrator as his medium, Robil translates the science he sees onto the screen. Recently, he submitted a piece entitled, “Auxin Motherboard” to the Kemper Museum of Contemporary Art in Kansas City in October 2019.

Even though Robil isn’t creating art now, he sees methods of art come up during his work in the lab.

“When I look at things in the microscope, I pay so much attention to detail that it slows me down,” Robil said. “The same is true when I am working in Adobe. I am very systematic about it. I feel like, in my head, I have an assembly line on how things are going to be done. I know a lot of artists are a lot like that. They are very organized, and they are very systematic…. Some of the technical stuff I bring to art, while I also bring some of my creative stuff to my science. So, there is a very good symbiotic relationship between the two.”

According to David Epstein, science journalist and author, scientists in general are no more likely to have artistic hobbies than the general public, but researchers at UCLA continue to be intrigued by the parallels and intersections of art and science.

“I see evidence of the interdependency of art and science every day. Just last week I had a wonderful conversation about a symposium on the physics of music,” said Pat Okker, the dean of the College of Arts and Science.

Carlos Rivera — a fourth-year graduate student who studies brain biology in Tucker Hall — is similar to Robil in his love for both art and science. In high school, one of Rivera’s drawings was chosen for the Missouri Fine Arts Academy.

“I always like to incorporate art into all the things I can do,” Rivera said. “I haven’t done it in a while, but when I first started off here at Mizzou I was taking pictures of brains, and in order to get good quality pictures you kind of have to know how things contrast against each other.”

Rivera would take pictures of fly brains, which required special instruments and precision. Now, Rivera is working on a mural of R2D2 shooting glial cells instead of lasers. A glial cell is a part of a neuron that provides support for the neuron, and scientists are still figuring out the intricacies of their function.

In order for scientists to make more discoveries, they need to tap into their artistic sides.

”Just in general, when you’re an artist you have to learn how to think creatively and a lot of scientists think that just comes with learning science, but you have to learn how to be creative sometimes,” said Katherine Guthrie, a graduate student working in the McSteen lab at Bond LSC. “So, when you have an art background, it’s a lot easier to think outside the box when you’re thinking about experiments or thinking about possible outcomes or planning for the future.”

Guthrie works with Robil in plant development genetics where they study how interrupting the auxin hormone pathway affects development. By understanding what it looks like when it’s broken, they can figure out how to make sure the pathway works best. On and off for the past 10 years, Guthrie has also been teaching art classes of every medium in school and studios.

Elementary School Art — Katherine Guthrie had elementary school children create an Andy Warhol-inspired project at an Art Camp she led in St. Charles, Missouri. | Photo contributed by Katherine Guthrie, Bond LSC

”The reason I’ve always loved art is because most people feel like they can’t do it and when they find out they can, it’s like this glorious epiphany like, ‘Wow! This is cool. I just made that.’” Guthrie said. “The reason I like science is because you get that epiphany, and the reason I like art is because you get to share that often.”

When art and science get the opportunity to interact, those outside of the scientific community are given a bridge to see what’s so exciting.

“I’m now realizing the reason I am excited about science fairs is that it’s also an opportunity for me to show my creativity,” Robil said. “You see these kids making volcanoes like every time in the science fair, and I think one of the reasons why they’re so keen to make these things is that they can also show how creative they are and also show the scientific aspect of it. So, there are people who are really really technical, but then I think when you add creativity to the technicality of science, that’s when it gets really interesting for me.”

#IAmScience Amanda Blythe

October 19, 2018 By Erica Overfelt in #IAmScience Tags: biochemistry

By Erica Overfelt | Bond LSC

You could credit a high school career fair to Amanda Blythe’s early success or simply luck.

Either way, Blythe was younger than most when her research was first published.

“I found a program at Washington University over the summer before my senior year of high school,” Blythe said. “They gave me a research project at the med school focusing on a rare genetic bone disorder. I did a lot of genetic sequencing looking for mutations, which led me to discovering a novel mutation, and we ended up publishing the data. It was a rare, lucky find.”

This find launched Blythe’s beginnings in the world of science.

“At first I didn’t realize how big it was. They included me on the entire review process, most of which I didn’t understand,” Blythe said. “When I told my mom, she seemed to indicate that it was a big deal, but I still did not completely understand the hype. The more people I told, the more I began to realize how great an honor it was. I felt really humbled. I was a summer student and I was only in high school. There were so many people helping me get on this path, it was surreal.”

Blythe’s path continued, leading her to Paula McSteen’s lab at Bond LSC.

“I showed her my resume, and she just kind of looked at it and asked, ‘How did this happen?’” Blythe said. “She was surprised, I told her how it was about being at the right place at the right time, and she was very impressed. It meant a lot coming from someone with that stature in science.”

Blythe is going on her fourth year in the lab. Currently, she works with specific corn mutants to better understand how to increase crop yield.

“Our lab is really focused on corn development — how it develops and what genes are behind that development,” Blythe said. “In order to do that we look at specific corn mutants. Each mutant will have a specific defect, and by understanding these defects we can better understand the function of important genes for proper development.”

Blythe has narrowed in on a mutant called Suppressor of Sessile Spikelet 3 (Sos3), which produces single instead of the normal paired spikelets. When you look at an Sos3 ear, you can see the gaps between the rows of kernels. Blythe is trying to identify the gene that produces paired spikelets in corn, which could lead to higher yield in other grasses such as rice and wheat.

Blythe sees the importance in creating high yield, but she doesn’t see herself doing plant research for the rest of her life. Blythe pictures herself in pharmaceutical research.

“I love my corn research, but I discovered the long-term end goal wasn’t my passion,” Blythe said. “I found that while writing certain project proposals that I was trying to link my project to public health. My PI even noticed and said I should link the two. So I tried it and discovered disease prevention was my true passion.”

Blythe’s fire for research won’t be burning out anytime soon, and her next published article could be in corn or pharmaceutical research, or even both.

“You know how some people get so excited for their goals? Research has become such a passion and goal for me,” Blythe said. “I have found something I get enjoyment from. From the tight-knit scientific community that I have to the experiences to getting new results, all of it continues to drive me every day.”

#IAmScience Janlo Robil

December 15, 2017 By Allison Scott in #IAmScience Tags: maize

Janlo Robil, a Ph.D. candidate in Plant Developmental Genetics, admires one of his plants. Robil works in the McSteen lab in Bond LSC. | photo by Allison Scott, Bond LSC

By Allison Scott | Bond Life Sciences Center

“#IAmScience because adding a small puzzle piece to the bigger picture is my source of joy.”

Janlo Robil found himself with a difficult decision when he entered a master’s program at Ateneo de Manila University in the Philippines.

His passion for insects made him want to pursue entomology, but the lack of coursework in the area made him consider other options. Not wanting to put off his studies for another year, Robil took a course called Plant Microtechnique. After that, he was hooked, a weird place to be for someone with no prior interest in plants.

“I found myself amazed by the diversity and intricacy of plant cells and tissues,” Robil said. “And studying these structures in the laboratory was even more interesting.”

From there, his passion only grew. It led him to apply for and be accepted as a Fulbright Scholar — a prestigious exchange program that allows recent graduates to pursue further education in over 140 countries. He chose to attend Mizzou over Iowa and North Carolina because of its strength in plant sciences.

Now, a year and half into a five-year Ph.D. program in plant developmental genetics, Robil works in Paula McSteen’s lab at Bond LSC.

“I was drawn to her research because it encompasses the areas of biology that I am truly fascinated by: plant morpho-anatomy, developmental biology and genetics,” Robil said. “For me, working in the McSteen lab is a unique opportunity to explore fundamental biological questions using an excellent model system, maize.”

Robil studies corn as a key component of his dissertation.

“The overarching theme of my dissertation is the role of plant hormone auxin in vein development and patterning in maize leaf,” Robil said. “I am interested on how the dynamics of auxin shape the formation and density of veins during different steps of leaf development.”

He chose this topic because of how influential it is to a variety of areas of science.

“This research is important to both fields of developmental biology and physiology because optimized density and spacing of leaf veins in C4 crops like maize is a key requirement for their efficient metabolism and productivity even in arid conditions.”

Robil is also able to better his home country while studying at Mizzou.

“Because Philippines is a developing country, conducting basic research is a luxury and we try to focus most of our resources to applied research.” Robil said. “The United States houses the opportunity to explore the basic side of research, which provides the foundation for applied research in the future.”

At Bond LSC, Robil has been able to take his research to the next level.

“I value the collaborative and interdisciplinary atmosphere here,” Robil said. “You can find experts from a variety of disciplines that you can consult or work with to find answers to your research problems.”

Those insights have helped Robil grow as a researcher and work toward his dream of helping alleviate world hunger. While that’s no small task, he tries to take it one day at a time.

“Never lose the wonder of discovery,” Robil said. “It may not always be that novel or significant, but discovering new things should be considered a personal success.”

#IAmScience Katy Guthrie

October 13, 2017 By Allison Scott in #IAmScience Tags: maize

By Allison Scott | Bond LSC

“#IAmScience because I want to take the knowledge I gain and teach it to other young scientists so they share in this excitement, too.”

Katy Guthrie grew up as one of five girls. All five sisters took very different paths —one ended up in hospital management, another in marketing and advertising, one became an engineer and the other works in logistics for a start up.

But Guthrie took a different route.

Her love of science started long before she enrolled in classes at Northwest Missouri State University, but there she discovered her true love of plants. Guthrie took a required botany class, and less than a week into the course she was hooked.

“All biology students had to take zoology and botany,” said Guthrie. “I had an awesome botany professor second semester of my freshman year — her enthusiasm for the subject was captivating — and she and I developed a great relationship. It was in that class I discovered that plants are what I want to study for the rest of my life.”

As part of Dr. Paula McSteen’s lab, Guthrie studies the reproductive organs of maize and how its genes allow it to produce flower-bearing structures in pairs, while other plants only produce these structures singly.

“If you count the number of rows on a corn cob, it’s always even,” Guthrie said. “That’s because maize produces two flowers at a time instead of one. My research is essentially trying to figure out which genes are responsible for that doubling trait.”

It’s not an easy process, though, so Guthrie nurtures a unique approach to finding the solutions.

“I take ears of corn that make one flower-bearing structure and work backwards to try and find what’s missing,” Guthrie said. “If I can find that, I can assume that’s what’s making the difference.”

Although her work can be painstaking, Guthrie noted that science is all about learning from mistakes.

Ultimately, Guthrie wants to duplicate the gene that causes the doubling trait in other crops, such as rice, wheat and barley. This could have a big impact on cereal crop reproduction.

“We’re hoping to apply what we learn about maize other crops,” Guthrie said.

After finishing her studies at Mizzou, Guthrie plans to return to the classroom as a professor, preferably teaching undergraduates.

“The whole reason I decided to go to graduate school was to be able to teach,” Guthrie said. “I want people who aren’t necessarily interested in science initially to get invested in it. I also want to incorporate research into the classes I’ll teach because not every college is a research campus like Mizzou.”

The evolution of a corn geneticist

June 7, 2017 By Jennifer Lu in Research Tags: maize, plant sciences

By Jennifer Lu |Bond LSC

When developmental plant geneticist Paula McSteen thinks about the specimens she studies, one word comes to mind: potential.

She thought it as she stood in the midst of the first corn field she ever planted as a post-doctoral fellow in corn genetics.

She thinks it as she counts kernels from corn crosses that will be sent to Hawaii, a hotspot for corn geneticists looking to add a second harvest to their research year.

And she sees it in the students she mentors as a professor of biological sciences at MU and a researcher at the Bond Life Sciences Center.

Embracing the corn

McSteen entered the field of corn genetics 21 years ago, as a post-doctoral fellow in Berkeley.

“What’s really amazing is that when you plant a field of corn, the field is just bare,” McSteen says.

“A few weeks later, you come back and your plants are this high,” she says, gesturing with her hands. “And a few weeks later, they’re this high. And a few weeks later, they’re massive and it’s all just coming from nothing. The instructions are there in the seeds, but otherwise the plant is taking nutrients and water from the soil and using the air and sun to generate sugar for growing. It’s amazing. You come back and you’ve got this whole field of corn.”

During her first corn season, McSteen remembers being surrounded as far as the eye can see by corn as tall as people. “I feel like that’s one reason why people get into corn. You’re not staring down into a microscope, you’re embracing it. It’s right there in front of you.”

The feeling hasn’t gone away.

“When I see my plants,” McSteen says, “I’m excited about what’s going on with them. What could be happening here? What’s the meaning of these results?”

McSteen, who is Irish, grew up far removed from the sunny cornfields she works in. As a child in Dublin, she wasn’t particular outdoorsy. When her family went camping by the sea over the summer holidays, McSteen spent most of her time reading books. Her favorite subject in school was science. By the time she sat for her high school leaving exam, her classes were mainly in geography, science or math.

“I’ve always been fascinated with genetics,” McSteen says. Ever since she learned about Punnett squares in high school, its puzzle-like quality has appealed to her. “I just loved that you could figure out what the prediction could be from a certain cross.”

She applied and was accepted to her top choice university, Trinity College Dublin, where she studied genetics. She went on to pursue a PhD in Norwich, England studying how snapdragons make flowers.

When it came time for her to do her post-doc, she had the choice to work on Arabidopsis, a popular plant model, or maize, a crop with many opportunities for research funding. She chose the latter. The decision changed the course of her career, from her research focus to her country of residence.

Corn brought her to California, Pennsylvania and then the University of Missouri, which has a long history of corn genetics.

Pollen — Researchers cross-pollinate corn by pouring pollen collected from the tassel over the ear. | Photograph by Jennifer Lu, Bond LSC

Everything we do starts with mutants

McSteen studies a part of corn plants called the meristem, which is filled with stem cells that become the reproductive organs of the plant: the tassel and the ears.

The tassel, where pollen is produced, is found at the top of the cornstalk, while the ears, which are the female reproductive organs, jut out from the sides. When and how they form depend on a growth hormone called auxin.

To understand auxin regulation, McSteen begins every summer with a field full of mutants. Each kernel contains a mutation, but it’s impossible to tell at first what is causing the mutation.

“To me, every single mutant is just potential. You can’t wait to find out what is mutated. You never know what you’re going to end up with.”

McSteen is interested in mutations that affect the tassels or ears. These plants produce ears with fewer kernels or tassels with fewer branches. Or they fail to make ears or tassels altogether. The defects are outward signs of problems in meristem development, and hint at disruptions to genes that are involved in how auxin is made, transported or perceived by the plant.

Once a mutant is identified, McSteen works backwards to find out which gene is causing the mutation, and where it is located on the chromosome. To date, her group has identified multiple genes related to auxin-mediated development, as well as two genes that affect the uptake or synthesis of essential nutrients.

A third project revolves around a strain of corn that produces half as many kernels as regular corn, causing it to look like grains such as rice or wheat. McSteen thinks that if they can understand what’s causing the shortfall in kernel development, it may be possible to engineer grains like rice and wheat to “double kernel” the way that corn does.

Ultimately, studying these genes help corn researchers to better understand plant development and improve yield.

Graduate student Eden Johnson photographs a mutant that has produced half as many rows of kernels. | Photograph by Jennifer Lu, Bond LSC

You always love the organism

To keep all their experiments going, the McSteen lab plants three acres of corn every summer. Each acre contains 750 rows; each row holds 30 plants.

With the aid of a hand held planter, they drop 67,500 kernels into the soil. Then they do what McSteen calls a lopsided “planter’s shuffle” to stamp the soil down so that it covers every kernel.

“You can do a whole acre of corn in a few hours,” she said. “It’s hard work. You’re sore afterwards.”

During Missouri summers, temperatures can reach over 100 degrees Fahrenheit. It feels even hotter when it rains. The ground is either hard as a rock before it rains or so muddy after it rains that researchers have to take care not to wrench their ankles in the thick muck.

McSteen has worked on corn for so long that she’s developed severe allergies to corn pollen. It’s not uncommon among corn researchers, but her allergies prevent her from taking part in the pollination step that takes place at the height of summer.

“You’re out there in 100-degree heat getting the job done,” she says. “It’s a real bonding experience for the lab.”

To pollinate the corn, they slip paper bags over the ears and tassel of their plants. Covering the ears prevents accidental fertilization of the ears from stray pollen blown about by the wind. The bag over the tassel allows researchers to collect the yellow powder that will be used for controlled pollination.

“The next day, you bang the tassel and the pollen falls out into the bag,” McSteen says. “Then you gather it all up and you pour it on the ear.” It’s possible to pollinate about 100 plants in an hour, but you have to start early and work quickly, McSteen says. Otherwise, all the pollen is dead by noon.

McSteen’s allergies prevent her from shelling corn as well, but she’s on deck for planting and harvest time and all the other stages in between.

“If you’re a corn geneticist, you’re out there working with the plants. You always love the organism.”

A Collaborative Community

“To be a corn geneticist, you have to be very organized and plan ahead,” McSteen says. Because it takes a long time to grow several generations of corn, she’s only beginning to see the results of experiments she started years ago.

As a way to increase productivity, corn researchers send their seeds to warm places such as Mexico, Chile or Hawaii that can accommodate a winter harvest.

In the lab, McSteen chooses kernels from carefully selected mutants to ship to an island in Hawaii. There, a company will plant and harvest the corn for her, but she usually sends two of her researchers down to take care of the pollinations themselves.

McSteen counts out thirteen yellow kernels that are shiny and mold-free. “Potential,” she says, as she slips the seeds in an envelope with the cross information labeled on the front.

A three week trip to Hawaii in the winter isn’t as exotic as it sounds, says Eden Johnson, a third year graduate student in McSteen’s lab. On the island, the beaches are rocky and full of riptides. “It is literally cornfields, one diner and a stop sign. The whole island exists for corn.”

“When you’re down there in Hawaii, you hang out with the other researchers,” McSteen says. “If their field is peaking and your field is not, then you’ll go help.”

In her experience, the corn community tends to be collaborative rather than competitive. She suspects it’s because everyone recognizes that corn takes a long time to grow.

“If you find out you’re working on similar things, you’ll work together, divide the work and do it together,” McSteen says. Researchers don’t race each other to be the first one to publish. “They won’t do that because they have respect for how long it takes to grow the corn.”

Katy Gurthrie removes a bag used to collect pollen from the tassel. | Photograph by Jennifer Lu, Bond LSC

Growing careers alongside corn

McSteen is as serious about mentorship as she is about corn. “It’s part of the job of being a professor”.

According to Katy Guthrie, a second year graduate student in the lab, McSteen takes a Goldilocks approach to managing her students.

Neither too hands on or too hands off, “it’s exactly what I need,” Guthrie says. “She’s kind of like my academic parent for the next five years.”

Back at Penn State, McSteen supervised a PhD student who was talented writer. “I noticed this and gave her opportunities to write.” McSteen introduced her to a science writer and encouraged her to spend a summer writing for a science publication. “Now she works for the National Academy of Sciences. I’m really proud of her, and I feel like she’ll have a big impact communicating science to the public.”

A post-doc wanted to do go into teaching, so McSteen invited her to co-teach her class. Her post-doc went on to become a teaching professor at Mizzou. Another student turned her research experience in mapping mutants in corn into a successful career at a corn company.

“I want to enable the people in my lab to reach their full potential,” McSteen says. “I always try to figure out what they want to do in the future and try and facilitate that.”

Critical transport: Bond LSC team finds boron vital for plant stem cells, corn reproduction

August 25, 2014 By Roger Meissen in Research Tags: boron, corn

Carbon’s next-door neighbor on the periodic table typically receives little attention, but when it comes to corn reproduction boron fills an important role.

According to University of Missouri scientists, tiny amounts of boron play a key part in the development of ears and tassels on every cornstalk. The July 2014 edition of the journal Plant Cell published this research.

“Boron deficiency was already known to cause plants to stop growing, but we showed a lack of boron actually causes a problem in the meristems, the stem cells of the plant,” said Paula McSteen, a Bond Life Sciences Center researcher. “That was completely unknown before, and for plant scientists that’s an important discovery.”

MU post doc Amanda Durkbak, Bond LSC researcher Paula McSteen, research specialist Sharon Pike and Bond LSC researcher Walter Gassmann — Amanda Durkbak, MU Biological Sciences post doc; Paula McSteen, Bond LSC researcher and associate professor of Biological Sciences; research specialist Sharon Pike; and Walter Gassmann, Bond LSC researcher and professor of Plant Sciences.

Meristems are a big deal to a plant. These pools of stem cells are the growing points for each plant, and every organ comes from them. They are how plants can survive for 500 or 5,000 years, continuously making new organs in the form of leaves, flowers, and seeds throughout its life.

“When you mow your grass, it keeps growing because of the meristems,” said Amanda Durbak, first author on the paper and MU biological sciences post doc. “In corn, there are actually hundreds of meristems at the tips and all sides of ears and tassels.”

But without enough boron, these growing points disintegrate, and, in corn, that means vegetation is stunted, tassels fail to develop properly and kernels don’t set on an ear. This leads to reduced yield. Missouri and the eastern half of the U.S. are typically plagued by boron-deficient soil, an essential micronutrient for crops like corn and soybeans, indicating that farmers need to supplement with boron to maximize yield.

The tassel-less mutant

The team’s discovery started with a stunted, little corn plant that just couldn’t grow tassels, only created a tiny ear and died within a few weeks. These maligned reproductive organs piqued McSteen’s interest and her team of collaborators set out to figure out which gene was affected in this mutant plant. Graduate student Kim Phillips mapped the mutation to a specific gene in the corn genome involved in transporting molecules across the plant membrane.

But, what was this defect preventing the plant from receiving? Two experiments helped find the answer.

They started by looking at similar genes in other plants and animals. Simon Malcomber of California State University-Long Beach compared the gene – named the tassel-less gene after its mutant appearance – to similar genes in other plants and animals. He found that many were known to make a protein that transports boron and a few other elements.

From field to frog

To clinch this hypothesis, McSteen looked to Bond LSC scientist Walter Gassmann and the African clawed frog. Gassmann harvests eggs from these frogs and uses them to “test” the function of genes from both plants and animals.

“What we do is we inject the frog egg with RNA made in a test tube from the corn’s DNA,” Gassmann said. “The egg is a single, living cell that will actually use the message provided by this RNA to make the boron transporting protein and put it in the egg’s membrane.”

Frog eggs don’t naturally have the ability to transport boron, so an uninjected egg in a solution of boron can’t move the element into the cell.

“Corn RNA provides the egg with instructions to make a boron transporter protein, so the boron solution should move from outside to inside the egg,” Durbak said. “The egg should swell, showing this protein moves boron, and, in fact, these eggs swell so much they explode.”

A tank and a bucket guaranteed boron was the culprit. Durbak went back to the cornfield, watering some mutant tassel-less corn with boron fertilizer and other mutant plants with only water.

Only the ones given boron recovered and grew like normal corn plants, showing that the mutant corn has difficulties obtaining enough boron under natural, low boron conditions without this boron transporter. The boron content of the plants were later tested at the MU Research Reactor and the MU Extension Soil and Plant Testing Laboratory, affirming their observations.

A closer look

But, what does boron deficiency look like on a cellular level?

To see, the team collaborated with biochemist Malcolm O’Neill at University of Georgia. He looked at the cell walls in the plant and discovered that the pectin was affected. Pectin stabilizes the plant cell wall, and many home canners know pectin for its help in making jelly and jam solidify. Pectin is strengthened when boron cross-links two carbohydrates together, giving rigidity to the plant cell wall.

“The effect is that it locks in the cellulose, so without it plant cells won’t have nearly the stability,” McSteen said. “What we think is going on is that plant meristems basically disintegrate because they don’t have the support of pectin.”

While McSteen’s team identified the gene that controls the protein for boron transport into a cell, a research team from Rutgers University identified a gene that controls the protein that transports boron out of a cell. See more about both studies in Plant Cell’s “In Brief” section.

The next step in this research is to look more closely at what happens in these boron-deficient cells early on as they develop to understand the mechanism of boron action in stem cells.

A grant from the National Science Foundation supported this research.

In addition to their Bond LSC appointments, Paula McSteen is an associate professor of biological sciences in the MU College of Arts and Sciences and Walter Gassmann is a professor of plant sciences in the MU College of Agriculture, Food and Natural Resources.